Data from IDeate-Lung01 trial will be presented at upcoming IASLC 2025 World Conference on Lung Cancer

First Breakthrough Therapy Designation for Daiichi Sankyo and Merck’s ifinatamab deruxtecan based on IDeate-Lung01 Phase 2 trial, with support from IDeate-PanTumor01 Phase 1/2 trial

Fourteenth Breakthrough Therapy Designation granted by FDA across the oncology portfolio of Daiichi Sankyo

BASKING RIDGE, NJ AND RAHWAY, NJ, – Ifinatamab deruxtecan (I-DXd) has been granted Breakthrough Therapy Designation (BTD) by the U.S. Food and Drug Administration (FDA) for the treatment of adult patients with extensive-stage small cell lung cancer with disease progression on or after platinum-based chemotherapy.

Ifinatamab deruxtecan is a specifically engineered, potential first-in-class B7-H3 directed DXd antibody drug conjugate (ADC) discovered by Daiichi Sankyo (TSE: 4568) and being jointly developed by Daiichi Sankyo and Merck (NYSE: MRK), known as MSD outside of the United States and Canada.

The FDA BTD is designed to accelerate the development and regulatory review of potential new medicines that are intended to treat a serious condition and address a significant unmet medical need. The medicine is required to have shown encouraging preliminary clinical results that demonstrate substantial improvement on a clinically significant endpoint over currently available medicines.

The FDA granted the BTD based on data from the IDeate-Lung01 Phase 2 trial, with support from the IDeate-PanTumor01 Phase 1/2 trial. Results from the primary analysis of IDeate-Lung01 will be presented in a late-breaking oral presentation at the IASLC 2025 World Conference on Lung Cancer hosted by the International Association for the Study of Lung Cancer (#WCLC25). This is the first BTD for ifinatamab deruxtecan and represents the first BTD since the start of the Daiichi Sankyo and Merck collaboration.

“This Breakthrough Therapy Designation granted by the FDA to ifinatamab deruxtecan highlights the urgent need for new treatment options for patients with pretreated extensive-stage small cell lung cancer,” said Ken Takeshita, MD, global head, R&D, Daiichi Sankyo. “We are committed to advancing this medicine with the goal of bringing the first B7-H3 directed antibody drug conjugate to patients in order to transform the outcomes of those facing this aggressive disease.”

“Patients living with extensive-stage small cell lung cancer often have limited therapeutic options following disease progression after standard of care treatments,” said Eliav Barr, MD, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories. “This Breakthrough Therapy Designation reinforces our confidence in the promise of ifinatamab deruxtecan to play an important role in the treatment of extensive-stage small cell lung cancer, and we are looking forward to sharing data at the upcoming IASLC 2025 World Conference on Lung Cancer that show the potential of this novel option.”

About IDeate-Lung01

IDeate-Lung01 is a global, multicenter, randomized, open-label, two-part Phase 2 trial evaluating the safety and efficacy of ifinatamab deruxtecan in patients with extensive-stage small cell lung cancer who were previously treated with at least one prior line of platinum-based chemotherapy and a maximum of three prior lines of therapy. Patients with asymptomatic brain metastases (untreated or previously treated) were eligible.

In the first part of the trial (dose optimization), patients were randomized 1:1 to receive ifinatamab deruxtecan 8 or 12 mg/kg intravenously Q3W. In the second part of the trial (dose expansion), patients received ifinatamab deruxtecan 12 mg/kg intravenously Q3W.

The primary endpoint is objective response rate (ORR) as assessed by blinded independent central review (BICR) per RECIST v1.1. Secondary endpoints included duration of response, progression-free survival, disease control rate, time to response, overall survival, pharmacokinetics and safety. Intracranial ORR was assessed by BICR as an exploratory analysis. 

IDeate-Lung01 enrolled 187 patients in Asia, Europe and North America. For more information about the trial, visit ClinicalTrials.gov

About IDeate-PanTumor01

IDeate-PanTumor01 is a global, multicenter, first-in-human, open-label Phase 1/2 trial evaluating the safety and efficacy of ifinatamab deruxtecan in patients with advanced/unresectable or metastatic solid tumors that are refractory or intolerable to standard treatment or for whom no standard treatment exists.

The Phase 1 part of the trial (dose escalation) is assessing the safety and tolerability of increasing doses of ifinatamab deruxtecan to determine the maximum tolerated dose and recommended dose for expansion (RDE). The Phase 2 part of the trial (dose expansion) is evaluating the safety and efficacy of ifinatamab deruxtecan at the RDE of 12 mg/kg in patients with squamous non-small cell lung cancer, metastatic castration-resistance prostate cancer or esophageal squamous cell carcinoma.

The dose escalation part of the trial is evaluating dose-limiting toxicity and safety. The dose expansion part of the trial is evaluating overall response rate, duration of response, disease control rate, progression-free survival, overall survival and safety. Pharmacokinetic endpoints, exploratory biomarker and immunogenicity endpoints will also be assessed.

IDeate-PanTumor01 enrolled approximately 250 patients in Asia and North America. For more information about the trial, visit ClinicalTrials.gov.

About small cell lung cancer

More than 2.48 million lung cancer cases were diagnosed globally in 2022. Small cell lung cancer (SCLC) is the second most common type of lung cancer, accounting for approximately 15% of cases. SCLC is aggressive and progresses rapidly to the distant metastatic stage, which has a low five-year survival rate. While conventional standard of care treatments for patients with advanced SCLC may help improve outcomes, there is a need for additional subsequent treatment approaches.

About B7-H3

B7-H3 is a transmembrane protein that belongs to the B7 family of proteins, which bind to the CD28 family of receptors that includes PD-1. B7-H3 is overexpressed in a wide range of cancer types, including SCLC, and its overexpression has been shown to correlate with poor prognosis, making B7-H3 a promising therapeutic target. There are currently no B7-H3 directed medicines approved for the treatment of any cancer.

About ifinatamab deruxtecan

Ifinatamab deruxtecan (I-DXd) is an investigational potential first-in-class B7-H3 directed ADC. Designed using Daiichi Sankyo’s proprietary DXd ADC Technology, ifinatamab deruxtecan is comprised of a humanized anti-B7-H3 IgG1 monoclonal antibody attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers.

Ifinatamab deruxtecan has been granted orphan drug designation by the U.S. FDA, European Commission, Japan Ministry of Health, Labour and Welfare and Taiwan Food and Drug Administration for the treatment of SCLC.

About the ifinatamab deruxtecan clinical development program

A comprehensive global clinical development program is underway evaluating the efficacy and safety of ifinatamab deruxtecan monotherapy and in combination with other anticancer medicines across multiple cancers.

About the Daiichi Sankyo and Merck collaboration

Daiichi Sankyo and Merck (known as MSD outside of the United States and Canada) entered into a global collaboration in October 2023 to jointly develop and commercialize patritumab deruxtecan (HER3-DXd), ifinatamab deruxtecan (I-DXd) and raludotatug deruxtecan (R-DXd), except in Japan where Daiichi Sankyo will maintain exclusive rights. Daiichi Sankyo will be solely responsible for manufacturing and supply. In August 2024, the global co-development and co-commercialization agreement was expanded to include gocatamig (MK-6070/DS3280), which the companies will jointly develop and commercialize worldwide, except in Japan where Merck & Co., Inc., Rahway, N.J., USA will maintain exclusive rights. Merck & Co., Inc., Rahway, N.J., USA will be solely responsible for manufacturing and supply for gocatamig.

About the ADC portfolio of Daiichi Sankyo

The Daiichi Sankyo ADC portfolio consists of seven ADCs in clinical development crafted from two distinct ADC technology platforms discovered in-house by Daiichi Sankyo.

The ADC platform furthest in clinical development is Daiichi Sankyo’s DXd ADC Technology where each ADC consists of a monoclonal antibody attached to a number of topoisomerase I inhibitor payloads (an exatecan derivative, DXd) via tetrapeptide-based cleavable linkers. The DXd ADC portfolio currently consists of ENHERTU®, a HER2 directed ADC, and DATROWAY®, a TROP2 directed ADC, which are being jointly developed and commercialized globally with AstraZeneca. Patritumab deruxtecan (HER3-DXd), a HER3 directed ADC, ifinatamab deruxtecan (I-DXd), a B7-H3 directed ADC, and raludotatug deruxtecan (R-DXd), a CDH6 directed ADC, are being jointly developed and commercialized globally with Merck & Co., Inc, Rahway, NJ, USA. DS-3939, a TA-MUC1 directed ADC, is being developed by Daiichi Sankyo.

The second Daiichi Sankyo ADC platform consists of a monoclonal antibody attached to a modified pyrrolobenzodiazepine (PBD) payload. DS-9606, a CLDN6 directed PBD ADC, is the first of several planned ADCs in clinical development utilizing this platform.

Ifinatamab deruxtecan, patritumab deruxtecan, raludotatug deruxtecan, DS-3939 and DS-9606 are investigational medicines that have not been approved for any indication in any country. Safety and efficacy have not been established.

About Daiichi Sankyo

Daiichi Sankyo is an innovative global healthcare company contributing to the sustainable development of society that discovers, develops and delivers new standards of care to enrich the quality of life around the world. With more than 120 years of experience, Daiichi Sankyo leverages its world-class science and technology to create new modalities and innovative medicines for people with cancer, cardiovascular and other diseases with high unmet medical needs. For more information, please visit www.daiichisankyo.com.

Merck’s focus on cancer

Every day, we follow the science as we work to discover innovations that can help patients, no matter what stage of cancer they have. As a leading oncology company, we are pursuing research where scientific opportunity and medical need converge, underpinned by our diverse pipeline of more than 25 novel mechanisms. With one of the largest clinical development programs across more than 30 tumor types, we strive to advance breakthrough science that will shape the future of oncology. By addressing barriers to clinical trial participation, screening and treatment, we work with urgency to reduce disparities and help ensure patients have access to high-quality cancer care. Our unwavering commitment is what will bring us closer to our goal of bringing life to more patients with cancer. For more information, visit www.merck.com/research/oncology.

About Merck

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

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Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024, and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

Media Contacts:

Merck:

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(617) 519-6264

julie.cunningham@merck.com

Michael McArdle

(908) 447-9453

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Daiichi Sankyo

Global/US Media:

Jennifer Brennan

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(908) 900-3183

Japan Media:

DS-PR@daiichisankyo.co.jp

Investor Contacts:

Merck

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Steven Graziano

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Daiichi Sankyo

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First and only systemic therapy to improve survival when used before and after surgery for patients with MIBC who are ineligible for cisplatin-based chemotherapy

First ever positive Phase 3 study in this cisplatin-ineligible patient population, representing significant advancement in MIBC


Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced positive topline results from the Phase 3 KEYNOTE-905 trial (also known as EV-303) in patients with muscle-invasive bladder cancer (MIBC) who are ineligible for cisplatin-based chemotherapy. In this study, KEYTRUDA® (pembrolizumab) plus Padcev (enfortumab vedotin-ejfv), given before and after surgery (radical cystectomy), demonstrated a statistically significant and clinically meaningful improvement in event-free survival (EFS), the study’s primary endpoint, as well as overall survival (OS) and pathologic complete response (pCR) rate, key secondary endpoints, compared to surgery (radical cystectomy) alone.

“Patients with muscle-invasive bladder cancer who are ineligible for cisplatin-based chemotherapy have not seen any treatment advance beyond surgery and face high rates of disease recurrence and a poor prognosis, even after having their bladder removed,” said Dr. Christof Vulsteke, MD, PhD, head of Integrated Cancer Center Ghent (IKG) and Clinical Trial Unit Oncology Ghent and KEYNOTE-905 principal investigator. “The KEYNOTE-905 study results mark the first time a systemic treatment approach, used before and after surgery, significantly extended survival over standard-of-care surgery in this population, demonstrating the potential of this combination to address a critical unmet need.”

The trial, evaluating Merck’s KEYTRUDA, an anti-PD-1 therapy, plus Padcev, an antibody-drug conjugate (ADC), was conducted in collaboration with Pfizer (previously Seagen) and Astellas and builds on the clinical success of this combination in locally advanced or metastatic urothelial cancer. The trial is continuing to evaluate the secondary EFS, OS, and pCR rate endpoints for neoadjuvant and adjuvant KEYTRUDA versus surgery alone as they continue to mature.

“There is a real and pressing need for more effective options for patients with bladder cancer who are ineligible for cisplatin-based treatment,” said Dr. Marjorie Green, senior vice president and head of oncology, global clinical development, Merck Research Laboratories. “The compelling survival results observed in this study reinforce the potential of combining KEYTRUDA with an antibody-drug conjugate to help address a significant unmet need in this vulnerable population.”

The safety profile of KEYTRUDA plus Padcev in this study was consistent with the known safety profiles of each agent. No new safety signals were identified with the combination. The companies plan to share these results with regulatory authorities worldwide and will present the data at an upcoming medical meeting.

KEYTRUDA plus Padcev is approved for the treatment of adult patients with locally advanced or metastatic urothelial cancer (la/mUC) in the U.S., the European Union (EU), Japan and several other countries around the world. KEYTRUDA as monotherapy is also approved in the U.S., EU, Japan and other countries for the treatment of certain patients with la/mUC or a type of non-muscle-invasive bladder cancer (NMIBC).

Five additional Phase 3 studies are currently evaluating KEYTRUDA across all stages of bladder cancer, including non-muscle-invasive, muscle-invasive and metastatic. Three of these studies are in MIBC including KEYNOTE-866 (NCT03924856), KEYNOTE-992 (NCT04241185) and KEYNOTE-B15 (NCT04700124), which is also known as EV-304 and is being conducted in collaboration with Pfizer and Astellas. KEYTRUDA is also being evaluated in combination with Bacillus Calmette-Guerin (BCG) in patients with NMIBC in the Phase 3 KEYNOTE-676 (NCT03711032) trial, and as adjuvant treatment in patients with localized muscle-invasive urothelial carcinoma and locally advanced urothelial carcinoma KEYNOTE-123 (NCT03244384).

About KEYNOTE-905/EV-303

KEYNOTE-905, also known as EV-303, is an open-label, randomized, multi-arm, controlled, Phase 3 trial (ClinicalTrials.gov, NCT03924895) evaluating perioperative KEYTRUDA, with or without Padcev, versus surgery alone in patients with MIBC who are either not eligible for or declined cisplatin-based chemotherapy. The trial enrolled 595 patients who were randomized to receive either:

  • Arm A: Three cycles of preoperative KEYTRUDA, followed by surgery to remove the bladder (radical cystectomy), followed by 14 cycles of postoperative KEYTRUDA;
  • Arm B: Surgery alone;
  • Arm C: Three cycles of preoperative KEYTRUDA plus enfortumab vedotin, followed by surgery to remove the bladder (radical cystectomy), followed postoperatively by six cycles of KEYTRUDA plus enfortumab vedotin and then eight cycles of KEYTRUDA alone.

The primary objective of this trial was to compare EFS between arm C and arm B, defined as the time from randomization to the first occurrence of any of the following events: progression of disease that precludes radical cystectomy (RC) surgery or failure to undergo RC surgery in participants with residual disease, gross residual disease left behind at the time of surgery, local or distant recurrence as assessed by imaging and/or biopsy or death due to any cause. The key secondary objectives were to compare OS and difference in pCR rate between arm C and arm B, as well as EFS, OS and the difference in pCR rate between arm A and arm B. The study remains ongoing to test hypotheses between arm A and arm B.

About bladder cancer

Bladder cancer is the ninth most common cancer worldwide, diagnosed in more than 614,000 patients each year globally. Muscle-invasive bladder cancer represents approximately 30% of all bladder cancer cases. The standard treatment for patients with MIBC is neoadjuvant cisplatin-based chemotherapy followed by surgery, which has been shown to prolong survival. However, up to half of patients with MIBC are not eligible to receive cisplatin and face limited treatment options, typically undergoing surgery alone.

About Merck’s early-stage cancer clinical program

Finding cancer at an earlier stage may give patients a greater chance of long-term survival. Many cancers are considered most treatable and potentially curable in their earliest stage of disease. Building on the strong understanding of the role of KEYTRUDA in later-stage cancers, Merck is studying KEYTRUDA in earlier disease states, with more than 25 ongoing registrational studies across multiple types of cancer.

About KEYTRUDA® (pembrolizumab) injection, 100 mg

KEYTRUDA is an anti-programmed death receptor-1 (PD-1) therapy that works by increasing the ability of the body’s immune system to help detect and fight tumor cells. KEYTRUDA is a humanized monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD- L1 and PD-L2, thereby activating T lymphocytes which may affect both tumor cells and healthy cells.

Merck has the industry’s largest immuno-oncology clinical research program. There are currently more than 1,600 trials studying KEYTRUDA across a wide variety of cancers and treatment settings. The KEYTRUDA clinical program seeks to understand the role of KEYTRUDA across cancers and the factors that may predict a patient’s likelihood of benefitting from treatment with KEYTRUDA, including exploring several different biomarkers.

Selected KEYTRUDA® (pembrolizumab) Indications in the U.S.

Urothelial Cancer

KEYTRUDA, in combination with enfortumab vedotin, is indicated for the treatment of adult patients with locally advanced or metastatic urothelial cancer.

KEYTRUDA, as a single agent, is indicated for the treatment of patients with locally advanced or metastatic urothelial carcinoma:

  • who are not eligible for any platinum-containing chemotherapy, or
  • who have disease progression during or following platinum-containing chemotherapy or within 12 months of neoadjuvant or adjuvant treatment with platinum-containing chemotherapy.

KEYTRUDA, as a single agent, is indicated for the treatment of patients with Bacillus Calmette-Guerin (BCG)-unresponsive, high-risk, non-muscle invasive bladder cancer (NMIBC) with carcinoma in situ (CIS) with or without papillary tumors who are ineligible for or have elected not to undergo cystectomy.

See additional selected KEYTRUDA indications in the U.S. after the Selected Important Safety Information.

Selected Important Safety Information for KEYTRUDA

Severe and Fatal Immune-Mediated Adverse Reactions

KEYTRUDA is a monoclonal antibody that belongs to a class of drugs that bind to either the programmed death receptor-1 (PD-1) or the programmed death ligand 1 (PD-L1), blocking the PD-1/PD-L1 pathway, thereby removing inhibition of the immune response, potentially breaking peripheral tolerance and inducing immune-mediated adverse reactions. Immune-mediated adverse reactions, which may be severe or fatal, can occur in any organ system or tissue, can affect more than one body system simultaneously, and can occur at any time after starting treatment or after discontinuation of treatment. Important immune-mediated adverse reactions listed here may not include all possible severe and fatal immune-mediated adverse reactions.

Monitor patients closely for symptoms and signs that may be clinical manifestations of underlying immune-mediated adverse reactions. Early identification and management are essential to ensure safe use of anti–PD-1/PD-L1 treatments. Evaluate liver enzymes, creatinine, and thyroid function at baseline and periodically during treatment. For patients with TNBC treated with KEYTRUDA in the neoadjuvant setting, monitor blood cortisol at baseline, prior to surgery, and as clinically indicated. In cases of suspected immune-mediated adverse reactions, initiate appropriate workup to exclude alternative etiologies, including infection. Institute medical management promptly, including specialty consultation as appropriate.

Withhold or permanently discontinue KEYTRUDA depending on severity of the immune-mediated adverse reaction. In general, if KEYTRUDA requires interruption or discontinuation, administer systemic corticosteroid therapy (1 to 2 mg/kg/day prednisone or equivalent) until improvement to Grade 1 or less. Upon improvement to Grade 1 or less, initiate corticosteroid taper and continue to taper over at least 1 month. Consider administration of other systemic immunosuppressants in patients whose adverse reactions are not controlled with corticosteroid therapy.

Immune-Mediated Pneumonitis

KEYTRUDA can cause immune-mediated pneumonitis. The incidence is higher in patients who have received prior thoracic radiation. Immune-mediated pneumonitis occurred in 3.4% (94/2799) of patients receiving KEYTRUDA, including fatal (0.1%), Grade 4 (0.3%), Grade 3 (0.9%), and Grade 2 (1.3%) reactions. Systemic corticosteroids were required in 67% (63/94) of patients. Pneumonitis led to permanent discontinuation of KEYTRUDA in 1.3% (36) and withholding in 0.9% (26) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, 23% had recurrence. Pneumonitis resolved in 59% of the 94 patients.

Pneumonitis occurred in 8% (31/389) of adult patients with cHL receiving KEYTRUDA as a single agent, including Grades 3-4 in 2.3% of patients. Patients received high-dose corticosteroids for a median duration of 10 days (range: 2 days to 53 months). Pneumonitis rates were similar in patients with and without prior thoracic radiation. Pneumonitis led to discontinuation of KEYTRUDA in 5.4% (21) of patients. Of the patients who developed pneumonitis, 42% interrupted KEYTRUDA, 68% discontinued KEYTRUDA, and 77% had resolution.

Pneumonitis occurred in 7% (41/580) of adult patients with resected NSCLC who received KEYTRUDA as a single agent for adjuvant treatment of NSCLC, including fatal (0.2%), Grade 4 (0.3%), and Grade 3 (1%) adverse reactions. Patients received high-dose corticosteroids for a median duration of 10 days (range: 1 day to 2.3 months). Pneumonitis led to discontinuation of KEYTRUDA in 26 (4.5%) of patients. Of the patients who developed pneumonitis, 54% interrupted KEYTRUDA, 63% discontinued KEYTRUDA, and 71% had resolution.

Immune-Mediated Colitis

KEYTRUDA can cause immune-mediated colitis, which may present with diarrhea. Cytomegalovirus infection/reactivation has been reported in patients with corticosteroid-refractory immune-mediated colitis. In cases of corticosteroid-refractory colitis, consider repeating infectious workup to exclude alternative etiologies. Immune-mediated colitis occurred in 1.7% (48/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (1.1%), and Grade 2 (0.4%) reactions. Systemic corticosteroids were required in 69% (33/48); additional immunosuppressant therapy was required in 4.2% of patients. Colitis led to permanent discontinuation of KEYTRUDA in 0.5% (15) and withholding in 0.5% (13) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, 23% had recurrence. Colitis resolved in 85% of the 48 patients.

Hepatotoxicity and Immune-Mediated Hepatitis

KEYTRUDA as a Single Agent

KEYTRUDA can cause immune-mediated hepatitis. Immune-mediated hepatitis occurred in 0.7% (19/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (0.4%), and Grade 2 (0.1%) reactions. Systemic corticosteroids were required in 68% (13/19) of patients; additional immunosuppressant therapy was required in 11% of patients. Hepatitis led to permanent discontinuation of KEYTRUDA in 0.2% (6) and withholding in 0.3% (9) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, none had recurrence. Hepatitis resolved in 79% of the 19 patients.

KEYTRUDA With Axitinib

KEYTRUDA in combination with axitinib can cause hepatic toxicity. Monitor liver enzymes before initiation of and periodically throughout treatment. Consider monitoring more frequently as compared to when the drugs are administered as single agents. For elevated liver enzymes, interrupt KEYTRUDA and axitinib, and consider administering corticosteroids as needed. With the combination of KEYTRUDA and axitinib, Grades 3 and 4 increased alanine aminotransferase (ALT) (20%) and increased aspartate aminotransferase (AST) (13%) were seen at a higher frequency compared to KEYTRUDA alone. Fifty-nine percent of the patients with increased ALT received systemic corticosteroids. In patients with ALT ≥3 times upper limit of normal (ULN) (Grades 2-4, n=116), ALT resolved to Grades 0-1 in 94%. Among the 92 patients who were rechallenged with either KEYTRUDA (n=3) or axitinib (n=34) administered as a single agent or with both (n=55), recurrence of ALT ≥3 times ULN was observed in 1 patient receiving KEYTRUDA, 16 patients receiving axitinib, and 24 patients receiving both. All patients with a recurrence of ALT ≥3 ULN subsequently recovered from the event.

Immune-Mediated Endocrinopathies

Adrenal Insufficiency

KEYTRUDA can cause primary or secondary adrenal insufficiency. For Grade 2 or higher, initiate symptomatic treatment, including hormone replacement as clinically indicated. Withhold KEYTRUDA depending on severity. Adrenal insufficiency occurred in 0.8% (22/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (0.3%), and Grade 2 (0.3%) reactions. Systemic corticosteroids were required in 77% (17/22) of patients; of these, the majority remained on systemic corticosteroids. Adrenal insufficiency led to permanent discontinuation of KEYTRUDA in <0.1% (1) and withholding in 0.3% (8) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement.

Hypophysitis

KEYTRUDA can cause immune-mediated hypophysitis. Hypophysitis can present with acute symptoms associated with mass effect such as headache, photophobia, or visual field defects. Hypophysitis can cause hypopituitarism. Initiate hormone replacement as indicated. Withhold or permanently discontinue KEYTRUDA depending on severity. Hypophysitis occurred in 0.6% (17/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (0.3%), and Grade 2 (0.2%) reactions. Systemic corticosteroids were required in 94% (16/17) of patients; of these, the majority remained on systemic corticosteroids. Hypophysitis led to permanent discontinuation of KEYTRUDA in 0.1% (4) and withholding in 0.3% (7) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement.

Thyroid Disorders

KEYTRUDA can cause immune-mediated thyroid disorders. Thyroiditis can present with or without endocrinopathy. Hypothyroidism can follow hyperthyroidism. Initiate hormone replacement for hypothyroidism or institute medical management of hyperthyroidism as clinically indicated. Withhold or permanently discontinue KEYTRUDA depending on severity. Thyroiditis occurred in 0.6% (16/2799) of patients receiving KEYTRUDA, including Grade 2 (0.3%). None discontinued, but KEYTRUDA was withheld in <0.1% (1) of patients.

Hyperthyroidism occurred in 3.4% (96/2799) of patients receiving KEYTRUDA, including Grade 3 (0.1%) and Grade 2 (0.8%). It led to permanent discontinuation of KEYTRUDA in <0.1% (2) and withholding in 0.3% (7) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement. Hypothyroidism occurred in 8% (237/2799) of patients receiving KEYTRUDA, including Grade 3 (0.1%) and Grade 2 (6.2%). It led to permanent discontinuation of KEYTRUDA in <0.1% (1) and withholding in 0.5% (14) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement. The majority of patients with hypothyroidism required long-term thyroid hormone replacement. The incidence of new or worsening hypothyroidism was higher in 1185 patients with HNSCC, occurring in 16% of patients receiving KEYTRUDA as a single agent or in combination with platinum and FU, including Grade 3 (0.3%) hypothyroidism. The incidence of new or worsening hypothyroidism was higher in 389 adult patients with cHL (17%) receiving KEYTRUDA as a single agent, including Grade 1 (6.2%) and Grade 2 (10.8%) hypothyroidism. The incidence of new or worsening hyperthyroidism was higher in 580 patients with resected NSCLC, occurring in 11% of patients receiving KEYTRUDA as a single agent as adjuvant treatment, including Grade 3 (0.2%) hyperthyroidism. The incidence of new or worsening hypothyroidism was higher in 580 patients with resected NSCLC, occurring in 22% of patients receiving KEYTRUDA as a single agent as adjuvant treatment (KEYNOTE-091), including Grade 3 (0.3%) hypothyroidism.

Type 1 Diabetes Mellitus (DM), Which Can Present With Diabetic Ketoacidosis

Monitor patients for hyperglycemia or other signs and symptoms of diabetes. Initiate treatment with insulin as clinically indicated. Withhold KEYTRUDA depending on severity. Type 1 DM occurred in 0.2% (6/2799) of patients receiving KEYTRUDA. It led to permanent discontinuation in <0.1% (1) and withholding of KEYTRUDA in <0.1% (1) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement.

Immune-Mediated Nephritis With Renal Dysfunction

KEYTRUDA can cause immune-mediated nephritis. Immune-mediated nephritis occurred in 0.3% (9/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (0.1%), and Grade 2 (0.1%) reactions. Systemic corticosteroids were required in 89% (8/9) of patients. Nephritis led to permanent discontinuation of KEYTRUDA in 0.1% (3) and withholding in 0.1% (3) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, none had recurrence. Nephritis resolved in 56% of the 9 patients.

Immune-Mediated Dermatologic Adverse Reactions

KEYTRUDA can cause immune-mediated rash or dermatitis. Exfoliative dermatitis, including Stevens-Johnson syndrome, drug rash with eosinophilia and systemic symptoms, and toxic epidermal necrolysis, has occurred with anti– PD-1/PD-L1 treatments. Topical emollients and/or topical corticosteroids may be adequate to treat mild to moderate nonexfoliative rashes. Withhold or permanently discontinue KEYTRUDA depending on severity. Immune-mediated dermatologic adverse reactions occurred in 1.4% (38/2799) of patients receiving KEYTRUDA, including Grade 3 (1%) and Grade 2 (0.1%) reactions. Systemic corticosteroids were required in 40% (15/38) of patients. These reactions led to permanent discontinuation in 0.1% (2) and withholding of KEYTRUDA in 0.6% (16) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, 6% had recurrence. The reactions resolved in 79% of the 38 patients.

Other Immune-Mediated Adverse Reactions

The following clinically significant immune-mediated adverse reactions occurred at an incidence of <1% (unless otherwise noted) in patients who received KEYTRUDA or were reported with the use of other anti–PD-1/PD-L1 treatments. Severe or fatal cases have been reported for some of these adverse reactions. Cardiac/Vascular: Myocarditis, pericarditis, vasculitis; Nervous System: Meningitis, encephalitis, myelitis and demyelination, myasthenic syndrome/myasthenia gravis (including exacerbation), Guillain-Barré syndrome, nerve paresis, autoimmune neuropathy; Ocular: Uveitis, iritis and other ocular inflammatory toxicities can occur. Some cases can be associated with retinal detachment. Various grades of visual impairment, including blindness, can occur. If uveitis occurs in combination with other immune-mediated adverse reactions, consider a Vogt-Koyanagi-Harada-like syndrome, as this may require treatment with systemic steroids to reduce the risk of permanent vision loss; Gastrointestinal: Pancreatitis, to include increases in serum amylase and lipase levels, gastritis, duodenitis; Musculoskeletal and Connective Tissue: Myositis/polymyositis, rhabdomyolysis (and associated sequelae, including renal failure), arthritis (1.5%), polymyalgia rheumatica; Endocrine: Hypoparathyroidism; Hematologic/Immune: Hemolytic anemia, aplastic anemia, hemophagocytic lymphohistiocytosis, systemic inflammatory response syndrome, histiocytic necrotizing lymphadenitis (Kikuchi lymphadenitis), sarcoidosis, immune thrombocytopenic purpura, solid organ transplant rejection, other transplant (including corneal graft) rejection.

Infusion-Related Reactions

KEYTRUDA can cause severe or life-threatening infusion-related reactions, including hypersensitivity and anaphylaxis, which have been reported in 0.2% of 2799 patients receiving KEYTRUDA. Monitor for signs and symptoms of infusion-related reactions. Interrupt or slow the rate of infusion for Grade 1 or Grade 2 reactions. For Grade 3 or Grade 4 reactions, stop infusion and permanently discontinue KEYTRUDA.

Complications of Allogeneic Hematopoietic Stem Cell Transplantation (HSCT)

Fatal and other serious complications can occur in patients who receive allogeneic HSCT before or after anti–PD-1/PD-L1 treatments. Transplant-related complications include hyperacute graft-versus-host disease (GVHD), acute and chronic GVHD, hepatic veno-occlusive disease after reduced intensity conditioning, and steroid-requiring febrile syndrome (without an identified infectious cause). These complications may occur despite intervening therapy between anti–PD-1/PD-L1 treatments and allogeneic HSCT. Follow patients closely for evidence of these complications and intervene promptly. Consider the benefit vs risks of using anti–PD-1/PD-L1 treatments prior to or after an allogeneic HSCT.

Increased Mortality in Patients With Multiple Myeloma

In trials in patients with multiple myeloma, the addition of KEYTRUDA to a thalidomide analogue plus dexamethasone resulted in increased mortality. Treatment of these patients with an anti–PD-1/PD-L1 treatment in this combination is not recommended outside of controlled trials.

Embryofetal Toxicity

Based on its mechanism of action, KEYTRUDA can cause fetal harm when administered to a pregnant woman. Advise women of this potential risk. In females of reproductive potential, verify pregnancy status prior to initiating KEYTRUDA and advise them to use effective contraception during treatment and for 4 months after the last dose.

Adverse Reactions

In KEYNOTE-006, KEYTRUDA was discontinued due to adverse reactions in 9% of 555 patients with advanced melanoma; adverse reactions leading to permanent discontinuation in more than one patient were colitis (1.4%), autoimmune hepatitis (0.7%), allergic reaction (0.4%), polyneuropathy (0.4%), and cardiac failure (0.4%). The most common adverse reactions (≥20%) with KEYTRUDA were fatigue (28%), diarrhea (26%), rash (24%), and nausea (21%).

In KEYNOTE-054, when KEYTRUDA was administered as a single agent to patients with stage III melanoma, KEYTRUDA was permanently discontinued due to adverse reactions in 14% of 509 patients; the most common (≥1%) were pneumonitis (1.4%), colitis (1.2%), and diarrhea (1%). Serious adverse reactions occurred in 25% of patients receiving KEYTRUDA. The most common adverse reaction (≥20%) with KEYTRUDA was diarrhea (28%). In KEYNOTE-716, when KEYTRUDA was administered as a single agent to patients with stage IIB or IIC melanoma, adverse reactions occurring in patients with stage IIB or IIC melanoma were similar to those occurring in 1011 patients with stage III melanoma from KEYNOTE-054.

In KEYNOTE-189, when KEYTRUDA was administered with pemetrexed and platinum chemotherapy in metastatic nonsquamous NSCLC, KEYTRUDA was discontinued due to adverse reactions in 20% of 405 patients. The most common adverse reactions resulting in permanent discontinuation of KEYTRUDA were pneumonitis (3%) and acute kidney injury (2%). The most common adverse reactions (≥20%) with KEYTRUDA were nausea (56%), fatigue (56%), constipation (35%), diarrhea (31%), decreased appetite (28%), rash (25%), vomiting (24%), cough (21%), dyspnea (21%), and pyrexia (20%).

In KEYNOTE-407, when KEYTRUDA was administered with carboplatin and either paclitaxel or paclitaxel protein-bound in metastatic squamous NSCLC, KEYTRUDA was discontinued due to adverse reactions in 15% of 101 patients. The most frequent serious adverse reactions reported in at least 2% of patients were febrile neutropenia, pneumonia, and urinary tract infection. Adverse reactions observed in KEYNOTE-407 were similar to those observed in KEYNOTE-189 with the exception that increased incidences of alopecia (47% vs 36%) and peripheral neuropathy (31% vs 25%) were observed in the KEYTRUDA and chemotherapy arm compared to the placebo and chemotherapy arm in KEYNOTE-407.

In KEYNOTE-042, KEYTRUDA was discontinued due to adverse reactions in 19% of 636 patients with advanced NSCLC; the most common were pneumonitis (3%), death due to unknown cause (1.6%), and pneumonia (1.4%). The most frequent serious adverse reactions reported in at least 2% of patients were pneumonia (7%), pneumonitis (3.9%), pulmonary embolism (2.4%), and pleural effusion (2.2%). The most common adverse reaction (≥20%) was fatigue (25%).

In KEYNOTE-010, KEYTRUDA monotherapy was discontinued due to adverse reactions in 8% of 682 patients with metastatic NSCLC; the most common was pneumonitis (1.8%). The most common adverse reactions (≥20%) were decreased appetite (25%), fatigue (25%), dyspnea (23%), and nausea (20%).

In KEYNOTE-671, adverse reactions occurring in patients with resectable NSCLC receiving KEYTRUDA in combination with platinum-containing chemotherapy, given as neoadjuvant treatment and continued as single-agent adjuvant treatment, were generally similar to those occurring in patients in other clinical trials across tumor types receiving KEYTRUDA in combination with chemotherapy.

The most common adverse reactions (reported in ≥20%) in patients receiving KEYTRUDA in combination with chemotherapy or chemoradiotherapy were fatigue/asthenia, nausea, constipation, diarrhea, decreased appetite, rash, vomiting, cough, dyspnea, pyrexia, alopecia, peripheral neuropathy, mucosal inflammation, stomatitis, headache, weight loss, abdominal pain, arthralgia, myalgia, insomnia, palmar-plantar erythrodysesthesia, urinary tract infection, hypothyroidism, radiation skin injury, dysphagia, dry mouth, and musculoskeletal pain.

In the neoadjuvant phase of KEYNOTE-671, when KEYTRUDA was administered in combination with platinum-containing chemotherapy as neoadjuvant treatment, serious adverse reactions occurred in 34% of 396 patients. The most frequent (≥2%) serious adverse reactions were pneumonia (4.8%), venous thromboembolism (3.3%), and anemia (2%). Fatal adverse reactions occurred in 1.3% of patients, including death due to unknown cause (0.8%), sepsis (0.3%), and immune-mediated lung disease (0.3%). Permanent discontinuation of any study drug due to an adverse reaction occurred in 18% of patients who received KEYTRUDA in combination with platinum-containing chemotherapy; the most frequent adverse reactions (≥1%) that led to permanent discontinuation of any study drug were acute kidney injury (1.8%), interstitial lung disease (1.8%), anemia (1.5%), neutropenia (1.5%), and pneumonia (1.3%).

Of the KEYTRUDA-treated patients who received neoadjuvant treatment, 6% of 396 patients did not receive surgery due to adverse reactions. The most frequent (≥1%) adverse reaction that led to cancellation of surgery in the KEYTRUDA arm was interstitial lung disease (1%).

In the adjuvant phase of KEYNOTE-671, when KEYTRUDA was administered as a single agent as adjuvant treatment, serious adverse reactions occurred in 14% of 290 patients. The most frequent serious adverse reaction was pneumonia (3.4%). One fatal adverse reaction of pulmonary hemorrhage occurred. Permanent discontinuation of KEYTRUDA due to an adverse reaction occurred in 12% of patients who received KEYTRUDA as a single agent, given as adjuvant treatment; the most frequent adverse reactions (≥1%) that led to permanent discontinuation of KEYTRUDA were diarrhea (1.7%), interstitial lung disease (1.4%), increased aspartate aminotransferase (1%), and musculoskeletal pain (1%).

Adverse reactions observed in KEYNOTE-091 were generally similar to those occurring in other patients with NSCLC receiving KEYTRUDA as a single agent, with the exception of hypothyroidism (22%), hyperthyroidism (11%), and pneumonitis (7%). Two fatal adverse reactions of myocarditis occurred.

In KEYNOTE-689, the most common adverse reactions (≥20%) in patients receiving KEYTRUDA were stomatitis (48%), radiation skin injury (40%), weight loss (36%), fatigue (33%), dysphagia (29%), constipation (27%), hypothyroidism (26%), nausea (24%), rash (22%), dry mouth (22%), diarrhea (22%), and musculoskeletal pain (22%).

In the neoadjuvant phase of KEYNOTE-689, of the 361 patients who received at least one dose of single agent KEYTRUDA, 11% experienced serious adverse reactions. Serious adverse reactions that occurred in more than one patient were pneumonia (1.4%), tumor hemorrhage (0.8%), dysphagia (0.6%), immune-mediated hepatitis (0.6%), cellulitis (0.6%), and dyspnea (0.6%). Fatal adverse reactions occurred in 1.1% of patients, including respiratory failure, clostridium infection, septic shock, and myocardial infarction (one patient each). Permanent discontinuation of KEYTRUDA due to an adverse reaction occurred in 2.8% of patients who received KEYTRUDA as neoadjuvant treatment. The most frequent adverse reaction which resulted in permanent discontinuation of neoadjuvant KEYTRUDA in more than one patient was arthralgia (0.6%).

Of the 361 patients who received KEYTRUDA as neoadjuvant treatment, 11% did not receive surgery. Surgical cancellation on the KEYTRUDA arm was due to disease progression in 4%, patient decision in 3%, adverse reactions in 1.4%, physician’s decision in 1.1%, unresectable tumor in 0.6%, loss of follow up in 0.3%, and use of non-study anti-cancer therapy in 0.3%.

Of the 323 KEYTRUDA-treated patients who received surgery following the neoadjuvant phase, 1.2% experienced delay of surgery (defined as on-study surgery occurring ≥9 weeks after initiation of neoadjuvant KEYTRUDA) due to adverse reactions, and 2.8% did not receive adjuvant treatment due to adverse reactions.

In the adjuvant phase of KEYNOTE-689, of the 255 patients who received at least one dose of KEYTRUDA, 38% experienced serious adverse reactions. The most frequent serious adverse reactions reported in ≥1% of KEYTRUDA- treated patients were pneumonia (2.7%), pyrexia (2.4%), stomatitis (2.4%), acute kidney injury (2.0%), pneumonitis (1.6%), COVID-19 (1.2%), death not otherwise specified (1.2%), diarrhea (1.2%), dysphagia (1.2%), gastrostomy tube site complication (1.2%), and immune-mediated hepatitis (1.2%). Fatal adverse reactions occurred in 5% of patients, including death not otherwise specified (1.2%), acute renal failure (0.4%), hypercalcemia (0.4%), pulmonary hemorrhage (0.4%), dysphagia/malnutrition (0.4%), mesenteric thrombosis (0.4%), sepsis (0.4%), pneumonia (0.4%), COVID-19 (0.4%), respiratory failure (0.4%), cardiovascular disorder (0.4%), and gastrointestinal hemorrhage (0.4%). Permanent discontinuation of adjuvant KEYTRUDA due to an adverse reaction occurred in 17% of patients. The most frequent (≥1%) adverse reactions that led to permanent discontinuation of adjuvant KEYTRUDA were pneumonitis, colitis, immune-mediated hepatitis, and death not otherwise specified.

In KEYNOTE-048, KEYTRUDA monotherapy was discontinued due to adverse events in 12% of 300 patients with HNSCC; the most common adverse reactions leading to permanent discontinuation were sepsis (1.7%) and pneumonia (1.3%). The most common adverse reactions (≥20%) were fatigue (33%), constipation (20%), and rash (20%).

In KEYNOTE-048, when KEYTRUDA was administered in combination with platinum (cisplatin or carboplatin) and FU chemotherapy, KEYTRUDA was discontinued due to adverse reactions in 16% of 276 patients with HNSCC. The most common adverse reactions resulting in permanent discontinuation of KEYTRUDA were pneumonia (2.5%), pneumonitis (1.8%), and septic shock (1.4%). The most common adverse reactions (≥20%) were nausea (51%), fatigue (49%), constipation (37%), vomiting (32%), mucosal inflammation (31%), diarrhea (29%), decreased appetite (29%), stomatitis (26%), and cough (22%).

In KEYNOTE-012, KEYTRUDA was discontinued due to adverse reactions in 17% of 192 patients with HNSCC. Serious adverse reactions occurred in 45% of patients. The most frequent serious adverse reactions reported in at least 2% of patients were pneumonia, dyspnea, confusional state, vomiting, pleural effusion, and respiratory failure. The most common adverse reactions (≥20%) were fatigue, decreased appetite, and dyspnea. Adverse reactions occurring in patients with HNSCC were generally similar to those occurring in patients with melanoma or NSCLC who received KEYTRUDA as a monotherapy, with the exception of increased incidences of facial edema and new or worsening hypothyroidism.

In KEYNOTE-204, KEYTRUDA was discontinued due to adverse reactions in 14% of 148 patients with cHL. Serious adverse reactions occurred in 30% of patients receiving KEYTRUDA; those ≥1% were pneumonitis, pneumonia, pyrexia, myocarditis, acute kidney injury, febrile neutropenia, and sepsis. Three patients died from causes other than disease progression: 2 from complications after allogeneic HSCT and 1 from unknown cause. The most common adverse reactions (≥20%) were upper respiratory tract infection (41%), musculoskeletal pain (32%), diarrhea (22%), and pyrexia, fatigue, rash, and cough (20% each).

In KEYNOTE-087, KEYTRUDA was discontinued due to adverse reactions in 5% of 210 patients with cHL. Serious adverse reactions occurred in 16% of patients; those ≥1% were pneumonia, pneumonitis, pyrexia, dyspnea, GVHD, and herpes zoster. Two patients died from causes other than disease progression: 1 from GVHD after subsequent allogeneic HSCT and 1 from septic shock. The most common adverse reactions (≥20%) were fatigue (26%), pyrexia (24%), cough (24%), musculoskeletal pain (21%), diarrhea (20%), and rash (20%).

In KEYNOTE-170, KEYTRUDA was discontinued due to adverse reactions in 8% of 53 patients with PMBCL. Serious adverse reactions occurred in 26% of patients and included arrhythmia (4%), cardiac tamponade (2%), myocardial infarction (2%), pericardial effusion (2%), and pericarditis (2%). Six (11%) patients died within 30 days of start of treatment. The most common adverse reactions (≥20%) were musculoskeletal pain (30%), upper respiratory tract infection and pyrexia (28% each), cough (26%), fatigue (23%), and dyspnea (21%).

In KEYNOTE-A39, when KEYTRUDA was administered in combination with enfortumab vedotin to patients with locally advanced or metastatic urothelial cancer (n=440), fatal adverse reactions occurred in 3.9% of patients, including acute respiratory failure (0.7%), pneumonia (0.5%), and pneumonitis/ILD (0.2%). Serious adverse reactions occurred in 50% of patients receiving KEYTRUDA in combination with enfortumab vedotin; the serious adverse reactions in ≥2% of patients were rash (6%), acute kidney injury (5%), pneumonitis/ILD (4.5%), urinary tract infection (3.6%), diarrhea (3.2%), pneumonia (2.3%), pyrexia (2%), and hyperglycemia (2%). Permanent discontinuation of KEYTRUDA occurred in 27% of patients. The most common adverse reactions (≥2%) resulting in permanent discontinuation of KEYTRUDA were pneumonitis/ILD (4.8%) and rash (3.4%). The most common adverse reactions (≥20%) occurring in patients treated with KEYTRUDA in combination with enfortumab vedotin were rash (68%), peripheral neuropathy (67%), fatigue (51%), pruritus (41%), diarrhea (38%), alopecia (35%), weight loss (33%), decreased appetite (33%), nausea (26%), constipation (26%), dry eye (24%), dysgeusia (21%), and urinary tract infection (21%).

In KEYNOTE-052, KEYTRUDA was discontinued due to adverse reactions in 11% of 370 patients with locally advanced or metastatic urothelial carcinoma. Serious adverse reactions occurred in 42% of patients; those ≥2% were urinary tract infection, hematuria, acute kidney injury, pneumonia, and urosepsis. The most common adverse reactions (≥20%) were fatigue (38%), musculoskeletal pain (24%), decreased appetite (22%), constipation (21%), rash (21%), and diarrhea (20%).

In KEYNOTE-045, KEYTRUDA was discontinued due to adverse reactions in 8% of 266 patients with locally advanced or metastatic urothelial carcinoma. The most common adverse reaction resulting in permanent discontinuation of KEYTRUDA was pneumonitis (1.9%). Serious adverse reactions occurred in 39% of KEYTRUDA-treated patients; those ≥2% were urinary tract infection, pneumonia, anemia, and pneumonitis. The most common adverse reactions (≥20%) in patients who received KEYTRUDA were fatigue (38%), musculoskeletal pain (32%), pruritus (23%), decreased appetite (21%), nausea (21%), and rash (20%).

In KEYNOTE-057, KEYTRUDA was discontinued due to adverse reactions in 11% of 148 patients with high-risk NMIBC. The most common adverse reaction resulting in permanent discontinuation of KEYTRUDA was pneumonitis (1.4%). Serious adverse reactions occurred in 28% of patients; those ≥2% were pneumonia (3%), cardiac ischemia (2%), colitis (2%), pulmonary embolism (2%), sepsis (2%), and urinary tract infection (2%). The most common adverse reactions (≥20%) were fatigue (29%), diarrhea (24%), and rash (24%).

Adverse reactions occurring in patients with MSI-H or dMMR CRC were similar to those occurring in patients with melanoma or NSCLC who received KEYTRUDA as a monotherapy.

In KEYNOTE-158 and KEYNOTE-164, adverse reactions occurring in patients with MSI-H or dMMR cancer were similar to those occurring in patients with other solid tumors who received KEYTRUDA as a single agent.

In KEYNOTE-811, fatal adverse reactions occurred in 3 patients who received KEYTRUDA in combination with trastuzumab and CAPOX (capecitabine plus oxaliplatin) or FP (5-FU plus cisplatin) and included pneumonitis in 2 patients and hepatitis in 1 patient. KEYTRUDA was discontinued due to adverse reactions in 13% of 350 patients with locally advanced unresectable or metastatic HER2-positive gastric or GEJ adenocarcinoma. Adverse reactions resulting in permanent discontinuation of KEYTRUDA in ≥1% of patients were pneumonitis (2.0%) and pneumonia (1.1%). In the KEYTRUDA arm vs placebo, there was a difference of ≥5% incidence between patients treated with KEYTRUDA vs standard of care for diarrhea (53% vs 47%), rash (35% vs 28%), hypothyroidism (11% vs 5%), and pneumonia (11% vs 5%).

In KEYNOTE-859, when KEYTRUDA was administered in combination with fluoropyrimidine- and platinum-containing chemotherapy, serious adverse reactions occurred in 45% of 785 patients. Serious adverse reactions in >2% of patients included pneumonia (4.1%), diarrhea (3.9%), hemorrhage (3.9%), and vomiting (2.4%). Fatal adverse reactions occurred in 8% of patients who received KEYTRUDA, including infection (2.3%) and thromboembolism (1.3%). KEYTRUDA was permanently discontinued due to adverse reactions in 15% of patients. The most common adverse reactions resulting in permanent discontinuation of KEYTRUDA (≥1%) were infections (1.8%) and diarrhea (1.0%). The most common adverse reactions (reported in ≥20%) in patients receiving KEYTRUDA in combination with chemotherapy were peripheral neuropathy (47%), nausea (46%), fatigue (40%), diarrhea (36%), vomiting (34%), decreased appetite (29%), abdominal pain (26%), palmar-plantar erythrodysesthesia syndrome (25%), constipation (22%), and weight loss (20%).

In KEYNOTE-590, when KEYTRUDA was administered with cisplatin and fluorouracil to patients with metastatic or locally advanced esophageal or GEJ (tumors with epicenter 1 to 5 centimeters above the GEJ) carcinoma who were not candidates for surgical resection or definitive chemoradiation, KEYTRUDA was discontinued due to adverse reactions in 15% of 370 patients. The most common adverse reactions resulting in permanent discontinuation of KEYTRUDA (≥1%) were pneumonitis (1.6%), acute kidney injury (1.1%), and pneumonia (1.1%). The most common adverse reactions (≥20%) with KEYTRUDA in combination with chemotherapy were nausea (67%), fatigue (57%), decreased appetite (44%), constipation (40%), diarrhea (36%), vomiting (34%), stomatitis (27%), and weight loss (24%).

Adverse reactions occurring in patients with esophageal cancer who received KEYTRUDA as a monotherapy were similar to those occurring in patients with melanoma or NSCLC who received KEYTRUDA as a monotherapy.

In KEYNOTE-A18, when KEYTRUDA was administered with CRT (cisplatin plus external beam radiation therapy [EBRT] followed by brachytherapy [BT]) to patients with FIGO 2014 Stage III-IVA cervical cancer, fatal adverse reactions occurred in 1.4% of 294 patients, including 1 case each (0.3%) of large intestinal perforation, urosepsis, sepsis, and vaginal hemorrhage. Serious adverse reactions occurred in 34% of patients; those ≥1% included urinary tract infection (3.1%), urosepsis (1.4%), and sepsis (1%). KEYTRUDA was discontinued for adverse reactions in 9% of patients. The most common adverse reaction (≥1%) resulting in permanent discontinuation was diarrhea (1%). For patients treated with KEYTRUDA in combination with CRT, the most common adverse reactions (≥10%) were nausea (56%), diarrhea (51%), urinary tract infection (35%), vomiting (34%), fatigue (28%), hypothyroidism (23%), constipation (20%), weight loss (19%), decreased appetite (18%), pyrexia (14%), abdominal pain and hyperthyroidism (13% each), dysuria and rash (12% each), back and pelvic pain (11% each), and COVID-19 (10%).

In KEYNOTE-826, when KEYTRUDA was administered in combination with paclitaxel and cisplatin or paclitaxel and carboplatin, with or without bevacizumab (n=307), to patients with persistent, recurrent, or first-line metastatic cervical cancer regardless of tumor PD-L1 expression who had not been treated with chemotherapy except when used concurrently as a radio-sensitizing agent, fatal adverse reactions occurred in 4.6% of patients, including 3 cases of hemorrhage, 2 cases each of sepsis and due to unknown causes, and 1 case each of acute myocardial infarction, autoimmune encephalitis, cardiac arrest, cerebrovascular accident, femur fracture with perioperative pulmonary embolus, intestinal perforation, and pelvic infection. Serious adverse reactions occurred in 50% of patients receiving KEYTRUDA in combination with chemotherapy with or without bevacizumab; those ≥3% were febrile neutropenia (6.8%), urinary tract infection (5.2%), anemia (4.6%), and acute kidney injury and sepsis (3.3% each).

KEYTRUDA was discontinued in 15% of patients due to adverse reactions. The most common adverse reaction resulting in permanent discontinuation (≥1%) was colitis (1%).

For patients treated with KEYTRUDA, chemotherapy, and bevacizumab (n=196), the most common adverse reactions (≥20%) were peripheral neuropathy (62%), alopecia (58%), anemia (55%), fatigue/asthenia (53%), nausea and neutropenia (41% each), diarrhea (39%), hypertension and thrombocytopenia (35% each), constipation and arthralgia (31% each), vomiting (30%), urinary tract infection (27%), rash (26%), leukopenia (24%), hypothyroidism (22%), and decreased appetite (21%).

For patients treated with KEYTRUDA in combination with chemotherapy with or without bevacizumab, the most common adverse reactions (≥20%) were peripheral neuropathy (58%), alopecia (56%), fatigue (47%), nausea (40%), diarrhea (36%), constipation (28%), arthralgia (27%), vomiting (26%), hypertension and urinary tract infection (24% each), and rash (22%).

In KEYNOTE-158, KEYTRUDA was discontinued due to adverse reactions in 8% of 98 patients with previously treated recurrent or metastatic cervical cancer. Serious adverse reactions occurred in 39% of patients receiving KEYTRUDA; the most frequent included anemia (7%), fistula, hemorrhage, and infections [except urinary tract infections] (4.1% each). The most common adverse reactions (≥20%) were fatigue (43%), musculoskeletal pain (27%), diarrhea (23%), pain and abdominal pain (22% each), and decreased appetite (21%).

In KEYNOTE-394, KEYTRUDA was discontinued due to adverse reactions in 13% of 299 patients with previously treated hepatocellular carcinoma. The most common adverse reaction resulting in permanent discontinuation of KEYTRUDA was ascites (2.3%). The most common adverse reactions in patients receiving KEYTRUDA (≥10%) were pyrexia (18%), rash (18%), diarrhea (16%), decreased appetite (15%), pruritus (12%), upper respiratory tract infection (11%), cough (11%), and hypothyroidism (10%).

In KEYNOTE-966, when KEYTRUDA was administered in combination with gemcitabine and cisplatin, KEYTRUDA was discontinued for adverse reactions in 15% of 529 patients with locally advanced unresectable or metastatic biliary tract cancer. The most common adverse reaction resulting in permanent discontinuation of KEYTRUDA (≥1%) was pneumonitis (1.3%). Adverse reactions leading to the interruption of KEYTRUDA occurred in 55% of patients. The most common adverse reactions or laboratory abnormalities leading to interruption of KEYTRUDA (≥2%) were decreased neutrophil count (18%), decreased platelet count (10%), anemia (6%), decreased white blood cell count (4%), pyrexia (3.8%), fatigue (3.0%), cholangitis (2.8%), increased ALT (2.6%), increased AST (2.5%), and biliary obstruction (2.3%).

In KEYNOTE-017 and KEYNOTE-913, adverse reactions occurring in patients with MCC (n=105) were generally similar to those occurring in patients with melanoma or NSCLC who received KEYTRUDA as a single agent.

In KEYNOTE-426, when KEYTRUDA was administered in combination with axitinib, fatal adverse reactions occurred in 3.3% of 429 patients. Serious adverse reactions occurred in 40% of patients, the most frequent (≥1%) were hepatotoxicity (7%), diarrhea (4.2%), acute kidney injury (2.3%), dehydration (1%), and pneumonitis (1%). Permanent discontinuation due to an adverse reaction occurred in 31% of patients; KEYTRUDA only (13%), axitinib only (13%), and the combination (8%); the most common were hepatotoxicity (13%), diarrhea/colitis (1.9%), acute kidney injury (1.6%), and cerebrovascular accident (1.2%). The most common adverse reactions (≥20%) were diarrhea (56%), fatigue/asthenia (52%), hypertension (48%), hepatotoxicity (39%), hypothyroidism (35%), decreased appetite (30%), palmar-plantar erythrodysesthesia (28%), nausea (28%), stomatitis/mucosal inflammation (27%), dysphonia (25%), rash (25%), cough (21%), and constipation (21%).

In KEYNOTE-564, when KEYTRUDA was administered as a single agent for the adjuvant treatment of renal cell carcinoma, serious adverse reactions occurred in 20% of patients receiving KEYTRUDA; the serious adverse reactions (≥1%) were acute kidney injury, adrenal insufficiency, pneumonia, colitis, and diabetic ketoacidosis (1% each). Fatal adverse reactions occurred in 0.2% including 1 case of pneumonia. Discontinuation of KEYTRUDA due to adverse reactions occurred in 21% of 488 patients; the most common (≥1%) were increased ALT (1.6%), colitis (1%), and adrenal insufficiency (1%). The most common adverse reactions (≥20%) were musculoskeletal pain (41%), fatigue (40%), rash (30%), diarrhea (27%), pruritus (23%), and hypothyroidism (21%).

In KEYNOTE-868, when KEYTRUDA was administered in combination with chemotherapy (paclitaxel and carboplatin) to patients with advanced or recurrent endometrial carcinoma (n=382), serious adverse reactions occurred in 35% of patients receiving KEYTRUDA in combination with chemotherapy, compared to 19% of patients receiving placebo in combination with chemotherapy (n=377). Fatal adverse reactions occurred in 1.6% of patients receiving KEYTRUDA in combination with chemotherapy, including COVID-19 (0.5%) and cardiac arrest (0.3%). KEYTRUDA was discontinued for an adverse reaction in 14% of patients. Adverse reactions occurring in patients treated with KEYTRUDA and chemotherapy were generally similar to those observed with KEYTRUDA alone or chemotherapy alone, with the exception of rash (33% all Grades; 2.9% Grades 3-4).

Adverse reactions occurring in patients with MSI-H or dMMR endometrial carcinoma who received KEYTRUDA as a single agent were similar to those occurring in patients with melanoma or NSCLC who received KEYTRUDA as a single agent.

Adverse reactions occurring in patients with TMB-H cancer were similar to those occurring in patients with other solid tumors who received KEYTRUDA as a single agent.

Adverse reactions occurring in patients with recurrent or metastatic cSCC or locally advanced cSCC were similar to those occurring in patients with melanoma or NSCLC who received KEYTRUDA as a monotherapy.

In KEYNOTE-522, when KEYTRUDA was administered with neoadjuvant chemotherapy (carboplatin and paclitaxel followed by doxorubicin or epirubicin and cyclophosphamide) followed by surgery and continued adjuvant treatment with KEYTRUDA as a single agent (n=778) to patients with newly diagnosed, previously untreated, high-risk early-stage TNBC, fatal adverse reactions occurred in 0.9% of patients, including 1 each of adrenal crisis, autoimmune encephalitis, hepatitis, pneumonia, pneumonitis, pulmonary embolism, and sepsis in association with multiple organ dysfunction syndrome and myocardial infarction. Serious adverse reactions occurred in 44% of patients receiving KEYTRUDA; those ≥2% were febrile neutropenia (15%), pyrexia (3.7%), anemia (2.6%), and neutropenia (2.2%). KEYTRUDA was discontinued in 20% of patients due to adverse reactions. The most common reactions (≥1%) resulting in permanent discontinuation were increased ALT (2.7%), increased AST (1.5%), and rash (1%). The most common adverse reactions (≥20%) in patients receiving KEYTRUDA were fatigue (70%), nausea (67%), alopecia (61%), rash (52%), constipation (42%), diarrhea and peripheral neuropathy (41% each), stomatitis (34%), vomiting (31%), headache (30%), arthralgia (29%), pyrexia (28%), cough (26%), abdominal pain (24%), decreased appetite (23%), insomnia (21%), and myalgia (20%).

In KEYNOTE-355, when KEYTRUDA and chemotherapy (paclitaxel, paclitaxel protein-bound, or gemcitabine and carboplatin) were administered to patients with locally recurrent unresectable or metastatic TNBC who had not been previously treated with chemotherapy in the metastatic setting (n=596), fatal adverse reactions occurred in 2.5% of patients, including cardio-respiratory arrest (0.7%) and septic shock (0.3%). Serious adverse reactions occurred in 30% of patients receiving KEYTRUDA in combination with chemotherapy; the serious reactions in ≥2% were pneumonia (2.9%), anemia (2.2%), and thrombocytopenia (2%). KEYTRUDA was discontinued in 11% of patients due to adverse reactions. The most common reactions resulting in permanent discontinuation (≥1%) were increased ALT (2.2%), increased AST (1.5%), and pneumonitis (1.2%). The most common adverse reactions (≥20%) in patients receiving KEYTRUDA in combination with chemotherapy were fatigue (48%), nausea (44%), alopecia (34%), diarrhea and constipation (28% each), vomiting and rash (26% each), cough (23%), decreased appetite (21%), and headache (20%).

Lactation

Because of the potential for serious adverse reactions in breastfed children, advise women not to breastfeed during treatment and for 4 months after the last dose.

Pediatric Use

In KEYNOTE-051, 173 pediatric patients (65 pediatric patients aged 6 months to younger than 12 years and 108 pediatric patients aged 12 years to 17 years) were administered KEYTRUDA 2 mg/kg every 3 weeks. The median duration of exposure was 2.1 months (range: 1 day to 25 months).

Adverse reactions that occurred at a ≥10% higher rate in pediatric patients when compared to adults were pyrexia (33%), leukopenia (30%), vomiting (29%), neutropenia (28%), headache (25%), abdominal pain (23%), thrombocytopenia (22%), Grade 3 anemia (17%), decreased lymphocyte count (13%), and decreased white blood cell count (11%).

Geriatric Use

Of the 564 patients with locally advanced or metastatic urothelial cancer treated with KEYTRUDA in combination with enfortumab vedotin, 44% (n=247) were 65-74 years and 26% (n=144) were 75 years or older. No overall differences in safety or effectiveness were observed between patients 65 years of age or older and younger patients. Patients 75 years of age or older treated with KEYTRUDA in combination with enfortumab vedotin experienced a higher incidence of fatal adverse reactions than younger patients. The incidence of fatal adverse reactions was 4% in patients younger than 75 and 7% in patients 75 years or older.

Additional Selected KEYTRUDA Indications in the U.S.

Melanoma

KEYTRUDA is indicated for the treatment of patients with unresectable or metastatic melanoma.

KEYTRUDA is indicated for the adjuvant treatment of adult and pediatric (12 years and older) patients with Stage IIB, IIC, or III melanoma following complete resection.

Non-Small Cell Lung Cancer

KEYTRUDA, in combination with pemetrexed and platinum chemotherapy, is indicated for the first-line treatment of patients with metastatic nonsquamous non-small cell lung cancer (NSCLC), with no EGFR or ALK genomic tumor aberrations.

KEYTRUDA, in combination with carboplatin and either paclitaxel or paclitaxel protein-bound, is indicated for the first-line treatment of patients with metastatic squamous NSCLC.

KEYTRUDA, as a single agent, is indicated for the first-line treatment of patients with NSCLC expressing PD-L1 [Tumor Proportion Score (TPS) ≥1%] as determined by an FDA-approved test, with no EGFR or ALK genomic tumor aberrations, and is:

  • Stage III where patients are not candidates for surgical resection or definitive chemoradiation, or
  • metastatic.

KEYTRUDA, as a single agent, is indicated for the treatment of patients with metastatic NSCLC whose tumors express PD-L1 (TPS ≥1%) as determined by an FDA-approved test, with disease progression on or after platinum-containing chemotherapy. Patients with EGFR or ALK genomic tumor aberrations should have disease progression on FDA-approved therapy for these aberrations prior to receiving KEYTRUDA.

KEYTRUDA is indicated for the treatment of patients with resectable (tumors ≥4 cm or node positive) NSCLC in combination with platinum-containing chemotherapy as neoadjuvant treatment, and then continued as a single agent as adjuvant treatment after surgery.

KEYTRUDA, as a single agent, is indicated as adjuvant treatment following resection and platinum-based chemotherapy for adult patients with Stage IB (T2a ≥4 cm), II, or IIIA NSCLC.

Malignant Pleural Mesothelioma

KEYTRUDA, in combination with pemetrexed and platinum chemotherapy, is indicated for the first-line treatment of adult patients with unresectable advanced or metastatic malignant pleural mesothelioma (MPM).

Head and Neck Squamous Cell Cancer

KEYTRUDA is indicated for the treatment of adult patients with resectable locally advanced head and neck squamous cell carcinoma (HNSCC) whose tumors express PD-L1 [Combined Positive Score (CPS) ≥1] as determined by an FDA-approved test, as a single agent as neoadjuvant treatment, continued as adjuvant treatment in combination with radiotherapy (RT) with or without cisplatin and then as a single agent.

KEYTRUDA, in combination with platinum and fluorouracil (FU), is indicated for the first-line treatment of patients with metastatic or with unresectable, recurrent HNSCC.

KEYTRUDA, as a single agent, is indicated for the first-line treatment of patients with metastatic or with unresectable, recurrent HNSCC whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test.

KEYTRUDA, as a single agent, is indicated for the treatment of patients with recurrent or metastatic HNSCC with disease progression on or after platinum-containing chemotherapy.

Classical Hodgkin Lymphoma

KEYTRUDA is indicated for the treatment of adult patients with relapsed or refractory classical Hodgkin lymphoma (cHL).

KEYTRUDA is indicated for the treatment of pediatric patients with refractory cHL, or cHL that has relapsed after 2 or more lines of therapy.

Primary Mediastinal Large B-Cell Lymphoma

KEYTRUDA is indicated for the treatment of adult and pediatric patients with refractory primary mediastinal large B-cell lymphoma (PMBCL), or who have relapsed after 2 or more prior lines of therapy. KEYTRUDA is not recommended for treatment of patients with PMBCL who require urgent cytoreductive therapy.

Microsatellite Instability-High or Mismatch Repair Deficient Cancer

KEYTRUDA is indicated for the treatment of adult and pediatric patients with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) solid tumors, as determined by an FDA-approved test, that have progressed following prior treatment and who have no satisfactory alternative treatment options.

Microsatellite Instability-High or Mismatch Repair Deficient Colorectal Cancer

KEYTRUDA is indicated for the treatment of patients with unresectable or metastatic MSI-H or dMMR colorectal cancer (CRC) as determined by an FDA-approved test.

Gastric Cancer

KEYTRUDA, in combination with trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy, is indicated for the first-line treatment of adults with locally advanced unresectable or metastatic HER2-positive gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test.

KEYTRUDA, in combination with fluoropyrimidine- and platinum-containing chemotherapy, is indicated for the first-line treatment of adults with locally advanced unresectable or metastatic HER2-negative gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors express PD-L1 (CPS ≥ 1) as determined by an FDA approved test.

Esophageal Cancer

KEYTRUDA is indicated for the treatment of patients with locally advanced or metastatic esophageal or gastroesophageal junction (GEJ) (tumors with epicenter 1 to 5 centimeters above the GEJ) carcinoma that is not amenable to surgical resection or definitive chemoradiation either:

  • in combination with platinum- and fluoropyrimidine-based chemotherapy for patients with tumors that express PD-L1 (CPS ≥ 1), or
  • as a single agent after one or more prior lines of systemic therapy for patients with tumors of squamous cell histology that express PD-L1 (CPS ≥10) as determined by an FDA-approved test.

Cervical Cancer

KEYTRUDA, in combination with chemoradiotherapy (CRT), is indicated for the treatment of patients with locally advanced cervical cancer involving the lower third of the vagina, with or without extension to pelvic sidewall, or hydronephrosis/non-functioning kidney, or spread to adjacent pelvic organs (FIGO 2014 Stage III-IVA).

KEYTRUDA, in combination with chemotherapy, with or without bevacizumab, is indicated for the treatment of patients with persistent, recurrent, or metastatic cervical cancer whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test.

KEYTRUDA, as a single agent, is indicated for the treatment of patients with recurrent or metastatic cervical cancer with disease progression on or after chemotherapy whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test.

Hepatocellular Carcinoma

KEYTRUDA is indicated for the treatment of patients with hepatocellular carcinoma (HCC) secondary to hepatitis B who have received prior systemic therapy other than a PD-1/PD-L1-containing regimen.

Biliary Tract Cancer

KEYTRUDA, in combination with gemcitabine and cisplatin, is indicated for the treatment of patients with locally advanced unresectable or metastatic biliary tract cancer (BTC).

Merkel Cell Carcinoma

KEYTRUDA is indicated for the treatment of adult and pediatric patients with recurrent locally advanced or metastatic Merkel cell carcinoma (MCC).

Renal Cell Carcinoma

KEYTRUDA, in combination with axitinib, is indicated for the first-line treatment of adult patients with advanced renal cell carcinoma (RCC).

KEYTRUDA is indicated for the adjuvant treatment of patients with RCC at intermediate-high or high risk of recurrence following nephrectomy, or following nephrectomy and resection of metastatic lesions.

Endometrial Carcinoma

KEYTRUDA, in combination with carboplatin and paclitaxel, followed by KEYTRUDA as a single agent, is indicated for the treatment of adult patients with primary advanced or recurrent endometrial carcinoma.

KEYTRUDA, as a single agent, is indicated for the treatment of adult patients with advanced endometrial carcinoma that is MSI-H or dMMR, as determined by an FDA-approved test, who have disease progression following prior systemic therapy in any setting and are not candidates for curative surgery or radiation.

Tumor Mutational Burden-High Cancer

KEYTRUDA is indicated for the treatment of adult and pediatric patients with unresectable or metastatic tumor mutational burden-high (TMB-H) [≥10 mutations/megabase (mut/Mb)] solid tumors, as determined by an FDA-approved test, that have progressed following prior treatment and who have no satisfactory alternative treatment options.

This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials. The safety and effectiveness of KEYTRUDA in pediatric patients with TMB-H central nervous system cancers have not been established.

Cutaneous Squamous Cell Carcinoma

KEYTRUDA is indicated for the treatment of patients with recurrent or metastatic cutaneous squamous cell carcinoma (cSCC) or locally advanced cSCC that is not curable by surgery or radiation.

Triple-Negative Breast Cancer

KEYTRUDA is indicated for the treatment of patients with high-risk early-stage triple-negative breast cancer (TNBC) in combination with chemotherapy as neoadjuvant treatment, and then continued as a single agent as adjuvant treatment after surgery.

KEYTRUDA, in combination with chemotherapy, is indicated for the treatment of patients with locally recurrent unresectable or metastatic TNBC whose tumors express PD-L1 (CPS ≥10) as determined by an FDA-approved test.

About Merck

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

About the Merck, Pfizer and Astellas collaboration

Merck previously entered a clinical collaboration agreement with Seagen and Astellas to evaluate the combination of Merck’s KEYTRUDA® (pembrolizumab) and Seagen’s and Astellas’ Padcev® (enfortumab vedotin-ejfv) in patients with muscle-invasive bladder cancer (MIBC) who are not eligible for or declined cisplatin-based chemotherapy. Pfizer Inc. successfully completed its acquisition of Seagen on December 14, 2023. Padcev® and the Padcev device are trademarks jointly owned by Agensys, Inc., and Seagen Inc. Pfizer Inc. completed its acquisition of Seagen on December 14, 2023.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA

This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

Please see Prescribing Information for KEYTRUDA (pembrolizumab) at http://www.merck.com/product/usa/pi_circulars/k/keytruda/keytruda_pi.pdf and Medication Guide for KEYTRUDA at http://www.merck.com/product/usa/pi_circulars/k/keytruda/keytruda_mg.pdf.


Media Contacts:

Julie Cunningham

(617) 519-6264

Marian Cutler

(973) 517-0519

Investor Contacts:

Peter Dannenbaum

(732) 594-1579

Source: Merck & Co., Inc.

  • Total Worldwide Sales Were $15.8 Billion, a Decrease of 2% From Second Quarter 2024 Both Nominally and Excluding the Impact of Foreign Exchange
    • KEYTRUDA Sales Were $8.0 Billion, Growth of 9% Both Nominally and Excluding the Impact of Foreign Exchange
    • WINREVAIR Sales Were $336 Million
    • Animal Health Sales Were $1.6 Billion, Growth of 11% Both Nominally and Excluding the Impact of Foreign Exchange
    • GARDASIL/GARDASIL 9 Sales Were $1.1 Billion, a Decline of 55% Both Nominally and Excluding the Impact of Foreign Exchange
  • GAAP EPS Was $1.76; Non-GAAP EPS Was $2.13; GAAP and Non-GAAP EPS Include a Charge of $0.07 per Share for Closing of Hengrui Pharma License Agreement
  • Announced Agreement To Acquire Verona Pharma and Its First-In-Class COPD Maintenance Treatment for Adults, Ohtuvayre®;1 Transaction Expected To Close in Fourth Quarter 2025
  • Announced Positive Topline Results From First Two Phase 3 CORALreef Trials of Enlicitide Decanoate for Treatment of Adults With Hyperlipidemia
  • Received FDA Approval of ENFLONSIA for Prevention of RSV Lower Respiratory Tract Disease in Infants Born During or Entering Their First RSV Season; CDC’s ACIP Recommended ENFLONSIA for Prevention of RSV in Infants Younger Than 8 Months of Age for Their First RSV Season
  • Announced Multiyear Optimization Initiative Anticipated To Result in Approximately $3.0 Billion of Annual Cost Savings by the End of 2027, To Be Fully Reinvested Into Strategic Growth Areas
  • Full-Year 2025 Financial Outlook
    • Narrows Expected Worldwide Sales Range To Be Between $64.3 Billion and $65.3 Billion
    • Narrows Expected Non-GAAP EPS Range To Be Between $8.87 and $8.97
    • Outlook Does Not Include Anticipated Impact of the Announced Acquisition of Verona Pharma

Merck & Co., Inc., Rahway, N.J., USA (NYSE: MRK), known as MSD outside the United States and Canada, today announced financial results for the second quarter of 2025.

“Earlier this month, we were pleased to announce our pending acquisition of Verona Pharma, which augments our portfolio and pipeline and is another example of acting decisively when science and value align,” said Robert M. Davis, chairman and chief executive officer. “Today, we announced a multiyear optimization initiative that will redirect investment and resources from more mature areas of our business to our burgeoning array of new growth drivers, further enable the transformation of our portfolio, and drive our next chapter of productive, innovation-driven growth. With these actions, I am confident that we are well positioned to generate near- and long-term value for our shareholders and, most importantly, deliver for our patients.”

Financial Summary

$ in millions, except EPS amounts

Second Quarter

2025 

2024 

Change

Change Ex-
Exchange

Sales

$15,806

$16,112

-2%

-2%

GAAP net income2

4,427

5,455

-19%

-17%

Non-GAAP net income that excludes certain items2,3*

5,366

5,809

-8%

-6%

GAAP EPS

1.76

2.14

-18%

-16%

Non-GAAP EPS that excludes certain items3*

2.13

2.28

-7%

-5%

*Refer to table on page 7.

For the second quarter of 2025, Generally Accepted Accounting Principles (GAAP) earnings per share (EPS) assuming dilution was $1.76 and non-GAAP EPS was $2.13. GAAP and non-GAAP EPS in the second quarter of 2025 include a charge of $0.07 per share for an upfront payment to Jiangsu Hengrui Pharmaceuticals Co., Ltd. (Hengrui Pharma) upon closing of a license agreement. Non-GAAP EPS excludes acquisition- and divestiture-related costs, costs related to restructuring programs, and income and losses from investments in equity securities. Non-GAAP EPS in the second quarter of 2025 also excludes tax benefits primarily resulting from favorable audit adjustments. Non-GAAP EPS in the second quarter of 2024 also excludes a tax benefit due to a reduction in reserves for unrecognized income tax benefits, resulting from the expiration of the statute of limitations for assessments related to the 2019 federal tax return year.

Year-to-date results can be found in the attached tables.

Second-Quarter Sales Performance
The following table reflects sales of the Company’s top products and significant performance drivers.

 

Second Quarter

$ in millions

2025 

2024 

Change

Change Ex-
Exchange

Commentary

Total Sales

$15,806

$16,112

-2%

-2%

 

Pharmaceutical

14,050

14,408

-2%

-3%

Decline primarily due to vaccines and immunology, partially offset by growth in oncology and cardiology.

KEYTRUDA

7,956

7,270

9%

9%

Growth driven by continued strong global demand from metastatic indications, including bladder, endometrial and gastric cancers, and increased global uptake in earlier-stage indications, including triple-negative breast cancer, renal cell carcinoma (RCC) and cervical cancer, as well as non-small cell lung cancer in the U.S.

GARDASIL/GARDASIL 9

1,126

2,478

-55%

-55%

Decline primarily due to lower demand in China. Excluding China, sales declined 3%, or 4% excluding impact of foreign exchange, reflecting lower demand in Japan following a national catch-up immunization program, as well as timing of public-sector purchases in certain international markets. U.S. sales increased 2% in the quarter.

JANUVIA/JANUMET

623

629

-1%

Decrease primarily attributable to lower demand in China, impacts of generic competition in most international markets, and lower demand in the U.S. due to competitive pressure, which were largely offset by higher net pricing in the U.S.

PROQUAD, M-M-R II and VARIVAX

609

617

-1%

-2%

Decrease primarily reflects lower U.S. sales due to unfavorable VARIVAX public-sector activity and M-M-R II private-sector buy-out, partially offset by partial replenishment of PROQUAD doses borrowed from the U.S. Centers for Disease Control and Prevention (CDC) Pediatric Vaccine Stockpile, and higher pricing.

BRIDION

461

455

1%

1%

Increase primarily due to higher demand in the U.S., partially offset by lower demand in most international markets due to ongoing generic competition.

Lynparza*

370

317

17%

15%

Growth primarily due to higher demand in the U.S. and certain international markets.

WINREVAIR

336

70

N/M

N/M

Growth reflects continued uptake since second-quarter 2024 launch in the U.S.

Lenvima*

265

249

6%

5%

Increase primarily due to higher sales in the U.S. reflecting higher demand, partially offset by lower pricing.

VAXNEUVANCE

229

189

21%

20%

Growth primarily due to favorable public-sector activity in the U.S. and increased demand in certain international markets, partially offset by lower demand in the U.S. and Japan due to competitive pressure.

PREVYMIS

228

188

21%

20%

Growth primarily due to higher demand in the U.S. and Europe, partially offset by lower demand in China due to generic competition.

WELIREG

162

126

29%

29%

Growth primarily driven by higher demand in the U.S. and early launch uptake in certain EU markets, partially offset by lower pricing in the U.S.

CAPVAXIVE

129

Represents continued uptake since third-quarter 2024 launch in the U.S.

SIMPONI

172

-100%

-100%

Marketing rights in former territories of the Company reverted to Johnson & Johnson on Oct. 1, 2024.

Animal Health

1,646

1,482

11%

11%

Growth primarily due to higher demand for Livestock products, as well as inclusion of sales from Elanco aqua business acquired in July 2024, higher pricing and improved supply.

Livestock

961

837

15%

16%

Growth primarily driven by higher demand across all species, as well as inclusion of sales from Elanco aqua business acquired in July 2024.

Companion Animal

685

645

6%

6%

Increase primarily driven by higher pricing. Sales of BRAVECTO were $335 million and $331 million in current and prior year quarters, respectively, which represents an increase of 1%, both nominally and excluding impact of foreign exchange.

Other Revenues**

110

222

-50%

-3%

Primarily due to unfavorable impact of revenue-hedging activities.

*Alliance revenue for this product represents the Company’s share of profits, which are product sales net of cost of sales and commercialization costs.

**Other revenues are comprised primarily of revenues from third-party manufacturing arrangements and miscellaneous corporate revenues, including revenue-hedging activities.

N/M- Not meaningful.

Second-Quarter Expense, EPS and Related Information
The table below presents selected expense information.

$ in millions

GAAP

Acquisition-
and
Divestiture-
Related Costs4

Restructuring
Costs

(Income)
Loss From
Investments
in Equity
Securities

Non-
GAAP3

Second Quarter 2025

         

Cost of sales

$3,557

$576

$165

$-

$2,816

Selling, general and administrative

2,649

15

1

2,633

Research and development

4,048

3

53

3,992

Restructuring costs

560

560

Other (income) expense, net

(7)

(61)

54

 

 

 

 

 

 

Second Quarter 2024

 

 

 

 

 

Cost of sales

$3,745

$606

$66

$-

$3,073

Selling, general and administrative

2,739

24

31

2,684

Research and development

3,500

20

3,480

Restructuring costs

80

80

Other (income) expense, net

42

(17)

(49)

108

GAAP Expense, EPS and Related Information
Gross margin was 77.5% for the second quarter of 2025 compared with 76.8% for the second quarter of 2024. The increase was primarily due to the favorable impact of product mix, partially offset by higher restructuring costs and inventory write-offs.

Selling, general and administrative (SG&A) expenses were $2.6 billion in the second quarter of 2025, a decrease of 3% compared with the second quarter of 2024. The decrease was primarily due to lower administrative, restructuring and promotional costs.

Research and development (R&D) expenses were $4.0 billion in the second quarter of 2025, an increase of 16% compared with the second quarter of 2024. The increase was primarily due to a $200 million charge for an upfront payment made in the second quarter of 2025 for a license agreement with Hengrui Pharma, increased clinical development spending, higher compensation and benefit costs, and higher restructuring costs.

Other (income) expense, net, was $7 million of income in the second quarter of 2025 compared with $42 million of expense in the second quarter of 2024.

The effective tax rate of 11.4% for the second quarter of 2025 includes a 2.9 percentage point favorable impact due to tax benefits primarily resulting from favorable audit adjustments.

GAAP EPS was $1.76 for the second quarter of 2025 compared with $2.14 for the second quarter of 2024. The decrease reflects increased operating expenses driven by higher restructuring costs and research and development spending, a charge related to the closing of a license agreement with Hengrui Pharma, unfavorable tax impacts, and the unfavorable impact of foreign exchange.

Non-GAAP Expense, EPS and Related Information
Non-GAAP gross margin was 82.2% for the second quarter of 2025 compared with 80.9% for the second quarter of 2024. The increase was primarily due to the favorable impact of product mix, partially offset by higher inventory write-offs.

Non-GAAP SG&A expenses were $2.6 billion in the second quarter of 2025, a decrease of 2% compared with the second quarter of 2024. The decrease was primarily due to lower administrative and promotional costs.

Non-GAAP R&D expenses were $4.0 billion in the second quarter of 2025, an increase of 15% compared with the second quarter of 2024. The increase was primarily due to a $200 million charge for an upfront payment made in the second quarter of 2025 for a license agreement with Hengrui Pharma, increased clinical development spending, and higher compensation and benefit costs.

Non-GAAP other (income) expense, net, was $54 million of expense in the second quarter of 2025 compared with $108 million of expense in the second quarter of 2024.

The non-GAAP effective tax rate was 15.0% for the second quarter of 2025.

Non-GAAP EPS was $2.13 for the second quarter of 2025 compared with $2.28 for the second quarter of 2024. The decrease reflects increased operating expenses driven by higher research and development spending, a charge related to the closing of a license agreement with Hengrui Pharma, and the unfavorable impact of foreign exchange.

A reconciliation of GAAP to non-GAAP net income and EPS is provided in the table that follows.

 

Second Quarter

$ in millions, except EPS amounts

2025 

2024 

EPS

 

 

GAAP EPS

$1.76

$2.14

Difference

0.37

0.14

Non-GAAP EPS that excludes items listed below3

$2.13

$2.28

 

 

 

Net Income

 

 

GAAP net income2

$4,427

$5,455

Difference

939

354

Non-GAAP net income that excludes items listed below2,3

$5,366

$5,809

 

 

 

Excluded Items:

 

 

Acquisition- and divestiture-related costs4

$594

$633

Restructuring costs

779

177

Income from investments in equity securities

(61)

(49)

Decrease to net income before taxes

1,312

761

Estimated income tax (benefit) expense5

(373)

(407)

Decrease to net income

$939

$354

Planned Acquisition of Verona Pharma
On July 9, 2025, the Company furthered its science-led business development strategy by announcing an agreement under which the Company, through a subsidiary, will acquire Verona Pharma plc (Verona Pharma) for $107 per American Depository Share, each of which represents eight Verona Pharma ordinary shares, for a total transaction value of approximately $10 billion. Through the acquisition, the Company will add Ohtuvayre, a first-in-class selective dual inhibitor of phosphodiesterase 3 and 4 (PDE3 and PDE4), to its growing cardio-pulmonary pipeline and portfolio.

The U.S. Food and Drug Administration (FDA) approved Ohtuvayre in June 2024 for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in adult patients. It is the first novel inhaled mechanism for the treatment of COPD in more than 20 years. The transaction is anticipated to close in the fourth quarter of 2025.

Pipeline and Portfolio Highlights
In the second quarter, the Company continued to advance its broad and diverse pipeline with multiple regulatory and clinical milestones.

In oncology, the FDA approved KEYTRUDA as part of a therapy regimen for the treatment of certain adult patients with resectable locally advanced head and neck squamous cell carcinoma (HNSCC), based on results from the Phase 3 KEYNOTE-689 trial. This approval is the first perioperative anti-PD-1 treatment regimen for adults with resectable locally advanced HNSCC whose tumors express PD-L1 (CPS ≥1). In addition, the Ministry of Health, Labor and Welfare (MHLW) in Japan approved WELIREG as monotherapy for the treatment of adults with von Hippel-Lindau (VHL) disease-associated tumors, and for adults with unresectable or metastatic RCC that has progressed after chemotherapy.

At the 2025 American Society of Clinical Oncology Annual Meeting, the Company announced new research across more than 25 types of cancer in multiple treatment settings. Data were presented for several candidates, including MK-1084, an investigational oral selective KRAS G12C inhibitor, and from the Company’s pipeline of antibody-drug conjugates (ADCs). The Company also presented data from Phase 3 trials evaluating new combination regimens with KEYTRUDA, and longer-term data for studies of KEYTRUDA and WELIREG, with the KEYTRUDA studies including people with earlier stages of cancer.

The Company announced results from the Phase 3 KEYNOTE-B96 trial (also known as ENGOT-ov65) evaluating KEYTRUDA plus chemotherapy, which met its primary endpoint of progression-free survival (PFS) for the treatment of patients with platinum-resistant recurrent ovarian cancer whose tumors express PD-L1 and in all comers, as well as a secondary endpoint of overall survival (OS) in patients whose tumors express PD-L1. In addition, a pre-specified interim analysis of the Phase 3 KEYNOTE-937 study found that compared to placebo, KEYTRUDA did not show a statistically significant improvement in the primary endpoint of recurrence-free survival for certain patients with hepatocellular carcinoma. Also, a pre-specified interim analysis of the Phase 3 LEAP-014 trial found that KEYTRUDA plus Lenvima, in combination with platinum-based chemotherapy, did not show a statistically significant improvement in its primary endpoint of OS compared to KEYTRUDA plus chemotherapy for the first-line treatment of patients with metastatic esophageal squamous cell carcinoma (ESCC).

In vaccines and infectious diseases, the Company received FDA approval of ENFLONSIA for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in newborns and infants who are born during or entering their first RSV season. ENFLONSIA is the first and only RSV preventive option administered to infants using the same dose regardless of weight. The CDC’s Advisory Committee on Immunization Practices (ACIP) also recommended ENFLONSIA for the prevention of RSV in infants younger than 8 months of age born during or entering their first RSV season. In addition, the Company announced initiation of the MOBILIZE-1 Phase 3 trial evaluating V181, an investigational single-dose quadrivalent vaccine for the prevention of dengue disease.

In addition, the FDA accepted a New Drug Application (NDA) for doravirine/islatravir, an investigational, once-daily, oral, two-drug regimen for the treatment of adults with virologically suppressed HIV-1 based on the Phase 3 MK-8591A-051 and MK-8591A-052 trials. The FDA set a Prescription Drug User Fee Act (PDUFA) date of April 28, 2026. The Company also announced the initiation of the EXPrESSIVE Phase 3 trials for MK-8527, its investigational once-monthly oral candidate for HIV pre-exposure prophylaxis (PrEP).

In cardiovascular disease, the Company announced positive topline results from Phase 3 CORALreef HeFH and CORALreef AddOn, the first two of three Phase 3 clinical trials evaluating the safety and efficacy of enlicitide decanoate, an investigational, oral proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor being evaluated for the treatment of adults with hyperlipidemia already on lipid-lowering therapies, including at least a statin. In both trials, enlicitide demonstrated statistically significant and clinically meaningful reductions in low-density lipoprotein cholesterol. If approved, it would be the first marketed oral PCSK9 inhibitor.

In addition, the FDA granted priority review for a new supplemental Biologics License Application for WINREVAIR seeking approval to update the U.S. product label based on compelling results from the Phase 3 ZENITH trial. The FDA has set a PDUFA date of Oct. 25, 2025. The Company also provided an update on the Phase 3 HYPERION study evaluating WINREVAIR in recently diagnosed adults with pulmonary arterial hypertension (PAH). In the study, WINREVAIR added on top of background therapy within 12 months after initial diagnosis of PAH demonstrated a statistically significant and clinically meaningful reduction in the risk of clinical worsening events when compared to placebo. Further, the MHLW in Japan approved sotatercept for the treatment of adults with PAH under the trademark AIRWIN. It is the first activin signaling inhibitor therapy for PAH approved in Japan.

In the Animal Health business, the FDA approved BRAVECTO QUANTUM, an injectable formulation of BRAVECTO for dogs for the treatment and persistent killing of fleas and ticks. In addition, the European Commission (EC) approved NUMELVI tablets for dogs, a once-daily, second-generation Janus kinase (JAK) inhibitor, indicated for the treatment of pruritus associated with allergic dermatitis including atopic dermatitis and treatment of clinical manifestations of atopic dermatitis.

Notable recent news releases on the Company’s pipeline and portfolio are provided in the table that follows. Visit the News Releases section of the Company’s website to read the releases*.

Oncology

FDA Approved KEYTRUDA for PD-L1+ Resectable Locally Advanced HNSCC as Neoadjuvant Treatment, Continued as Adjuvant Treatment Combined With Radiotherapy With or Without Cisplatin Then as a Single Agent; Based on Results From Phase 3 KEYNOTE-689 Trial

FDA Approved WELIREG for Treatment of Adults and Pediatric Patients 12 Years and Older With Locally Advanced, Unresectable, or Metastatic Pheochromocytoma or Paraganglioma; Based on Results From Phase 2 LITESPARK-015 Clinical Trial

Phase 3 KEYNOTE-B96 Trial Met Primary Endpoint of PFS in Patients With Platinum-Resistant Recurrent Ovarian Cancer Whose Tumors Expressed PD-L1 and in All Comers

KEYTRUDA Plus Trodelvy Reduced Risk of Disease Progression or Death by 35% Versus KEYTRUDA Plus Chemotherapy in First-Line PD-L1+ Metastatic Triple-Negative Breast Cancer; Based on Results From Phase 3 ASCENT-04/KEYNOTE-D19 Trial

MK-1084, an Investigational KRAS G12C Inhibitor, Showed Antitumor Activity in Phase 1 Trial of Patients With Advanced Colorectal Cancer and Non-Small Cell Lung Cancer Whose Tumors Harbor KRAS G12C Mutations

Investigational Zilovertamab Vedotin at 1.75 mg/kg Dose Plus Standard of Care Showed Promising Antitumor Activity, Including Complete Response Rate, in Patients With Relapsed/Refractory Diffuse Large B-Cell Lymphoma; Based on Results From Phase 2 WaveLINE-003 Trial

IDeate-Prostate01 Phase 3 Trial of Ifinatamab Deruxtecan Initiated in Patients With Pretreated Metastatic Castration-Resistant Prostate Cancer

IDeate-Esophageal01 Phase 3 Trial of Ifinatamab Deruxtecan Initiated in Certain Patients With Pretreated Advanced or Metastatic ESCC

Vaccines and
Infectious Diseases

FDA Approved ENFLONSIA for Prevention of RSV Lower Respiratory Tract Disease in Infants Born During or Entering Their First RSV Season; Based on Results From Phase 2b/3 CLEVER Trial

ACIP Recommended Use of ENFLONSIA for Prevention of RSV Lower Respiratory Tract Disease in Infants Younger Than 8 Months of Age Born During or Entering Their First RSV Season

FDA Accepted NDA for Doravirine/Islatravir, an Investigational, Once-Daily, Oral, Two-Drug Regimen for Treatment of Adults With Virologically Suppressed HIV-1; Based on Results From Phase 3 MK-8591A-051 and MK-8591A-052 Trials; FDA Set PDUFA Date of April 28, 2026

EXPrESSIVE Phase 3 Trials Initiated for Investigational Once-Monthly HIV Prevention Pill, MK-8527

The Company Initiated MOBILIZE-1 Phase 3 Study Evaluating Dengue Vaccine Candidate

Cardiovascular

FDA Granted Priority Review for WINREVAIR to Update Label Based on Results From ZENITH Trial; FDA Set PDUFA Date of Oct. 25, 2025

The Company Announced Positive Topline Results From First Two Phase 3 CORALreef Trials Evaluating Enlicitide Decanoate for the Treatment of Adults With Hyperlipidemia

Phase 3 HYPERION Study of WINREVAIR Met Primary Endpoint in Recently Diagnosed Adults With PAH

Animal Health

FDA Approved BRAVECTO QUANTUM

EC Approved NUMELVI Tablets for Dogs

*References to the Company’s name in the above news release titles have been modified for the purpose of this announcement.

New Multiyear Optimization Initiative, Which Includes a Restructuring Program
The Company launched a new multiyear optimization initiative to enable the transformation of its portfolio by generating an expected $3.0 billion in annual cost savings from productivity actions, which will be fully reinvested to support new product launches and its pipeline across multiple therapeutic areas.

In July 2025, as part of this initiative, the Company approved a new restructuring program, in which it expects to eliminate certain administrative, sales and R&D positions. The Company will, however, continue to hire employees into new roles across strategic growth areas of the business. In addition, the Company will reduce its global real estate footprint and continue to optimize its manufacturing network, aligning the geography of its global manufacturing to its customers and reflecting changes in the Company’s business.

The Company anticipates cumulative pretax costs related to the program to be approximately $3.0 billion. For the second quarter of 2025, the Company recorded charges in its GAAP results of $649 million related to this restructuring program.

The Company expects the actions under the restructuring program to result in annual cost savings of approximately $1.7 billion, which will be substantially realized by the end of 2027. This restructuring program is part of the multiyear optimization initiative expected to achieve $3.0 billion in annual cost savings by the end of 2027.

Manufacturing and R&D Investment
The Company continued to make long-term investments in its U.S. manufacturing and R&D capabilities. This includes the start of construction for a $1.0 billion, 470,000-square-foot state-of-the-art biologics center of excellence in Wilmington, Delaware, which will serve as a launch and commercial production facility and the primary U.S. manufacturing site for KEYTRUDA. In addition, the Company announced an $895 million expansion of its Animal Health manufacturing facility in De Soto, Kansas; the 200,000-square-foot facility will increase capacity for Animal Health vaccines and biologic products.

Full-Year 2025 Financial Outlook
The following table summarizes the Company’s full-year financial outlook.

 

Full Year 2025

 

Updated

Prior

Sales*

$64.3 billion to $65.3 billion

$64.1 billion to $65.6 billion

Non-GAAP Gross margin3

Approximately 82%

Approximately 82%

Non-GAAP Operating expenses3**

$25.6 billion to $26.4 billion

$25.6 billion to $26.6 billion

Non-GAAP Other (income) expense, net3

$300 million to $400 million expense

$300 million to $400 million expense

Non-GAAP Effective tax rate3

15.0% to 16.0%

15.5% to 16.5%

Non-GAAP EPS3***

$8.87 to $8.97

$8.82 to $8.97

Share count (assuming dilution)

Approximately 2.51 billion

Approximately 2.51 billion

*The Company does not have any non-GAAP adjustments to sales.

**Includes one-time R&D charges of $300 million for a milestone payment to LaNova Medicines Ltd. (LaNova) associated with the technology transfer for MK-2010 expected to be recorded in the third quarter of 2025 and $200 million for the upfront payment for the license agreement completed with Hengrui Pharma in the second quarter of 2025.

Outlook does not assume any additional significant potential business development transactions.

***Includes one-time charges totaling $0.16 per share associated with the payment for the LaNova technology transfer for MK-2010 and upfront payment to Hengrui Pharma.

The Company has not provided a reconciliation of forward-looking non-GAAP gross margin, non-GAAP operating expenses, non-GAAP other (income) expense, net, non-GAAP effective tax rate and non-GAAP EPS to the most directly comparable GAAP measures, given it cannot predict with reasonable certainty the amounts necessary for such a reconciliation, including intangible asset impairment charges, legal settlements, and income and losses from investments in equity securities either owned directly or through ownership interests in investment funds, without unreasonable effort. These items are inherently difficult to forecast and could have a significant impact on the Company’s future GAAP results.

The Company now expects full-year 2025 sales to be between $64.3 billion and $65.3 billion, including a revised negative impact of foreign exchange of approximately 0.5% at mid-July 2025 exchange rates.

The Company now expects its full-year non-GAAP effective income tax rate to be between 15.0% and 16.0%.

The Company now expects its full-year non-GAAP EPS to be between $8.87 and $8.97, including a revised negative impact of foreign exchange of approximately $0.15 per share. This revised non-GAAP EPS range continues to reflect the impacts of a one-time charge of $200 million (recorded in the second quarter of 2025) for an upfront payment made in connection with the closing of a license agreement with Hengrui Pharma and the one-time charge of $300 million (to be recorded in the third quarter of 2025) related to a payment to LaNova for the completion of the technology transfer for MK-2010, which will impact EPS by approximately $0.16 in the aggregate. In 2024, non-GAAP EPS of $7.65 was negatively impacted by a net charge of $1.28 per share related to certain asset acquisitions, licensing agreements and collaborations.

The financial outlook does not include the anticipated impact of the announced acquisition of Verona Pharma.

Consistent with past practice, the financial outlook does not assume additional significant potential business development transactions.

The $200 million of costs previously included in the Company’s financial outlook related to the impact of tariffs is unchanged pending the outcome of additional potential government actions.

Earnings Conference Call
Investors, journalists and the general public may access a live audio webcast of the call on Tuesday, July 29, at 9 a.m. ET via this weblink. A replay of the webcast, along with the sales and earnings news release, supplemental financial disclosures and slides highlighting the results, will be available on the Company’s website.

All participants may join the call by dialing (800) 369-3351 (U.S. and Canada Toll-Free) or (517) 308-9448 and using the access code 9818590.

About Our Company
At Merck & Co., Inc., Rahway, N.J., USA, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA
This news release of Merck & Co., Inc., Rahway, N.J., USA (the “Company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the Company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the Company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the Company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The Company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the Company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

Appendix
Generic product names are provided below.

Pharmaceutical
BRIDION (sugammadex)
CAPVAXIVE (Pneumococcal 21-valent Conjugate Vaccine)
ENFLONSIA (clesrovimab-cfor)
GARDASIL (Human Papillomavirus Quadrivalent [Types 6, 11, 16 and 18] Vaccine, Recombinant)
GARDASIL 9 (Human Papillomavirus 9-valent Vaccine, Recombinant)
JANUMET (sitagliptin and metformin HCl)
JANUVIA (sitagliptin)
KEYTRUDA (pembrolizumab)
Lenvima (lenvatinib)
Lynparza (olaparib)
M-M-R II (Measles, Mumps and Rubella Virus Vaccine Live)
PREVYMIS (letermovir)
PROQUAD (Measles, Mumps, Rubella and Varicella Virus Vaccine Live)
SIMPONI (golimumab)
VARIVAX (Varicella Virus Vaccine Live)
VAXNEUVANCE (Pneumococcal 15-valent Conjugate Vaccine)
WELIREG (belzutifan)
WINREVAIR (sotatercept-csrk)

Animal Health
BRAVECTO (fluralaner)
BRAVECTO QUANTUM (fluralaner for extended-release injectable suspension)
NUMELVI (atinvicitinib)

________________________________

1 All trademarks are property of their respective owners.

2 Net income attributable to the Company.

3 The Company is providing certain 2025 and 2024 non-GAAP information that excludes certain items because of the nature of these items and the impact they have on the analysis of underlying business performance and trends. Management believes that providing this information enhances investors’ understanding of the Company’s results because management uses non-GAAP results to assess performance. Management uses non-GAAP measures internally for planning and forecasting purposes and to measure the performance of the Company along with other metrics. In addition, annual employee compensation, including senior management’s compensation, is derived in part using a non-GAAP pretax income metric. This information should be considered in addition to, but not as a substitute for or superior to, information prepared in accordance with GAAP. For a description of the non-GAAP adjustments, see Table 2a attached to this release.

4 Reflects expenses related to business combinations, including the amortization of intangible assets, intangible asset impairment charges, and expense or income related to changes in the estimated fair value measurement of liabilities for contingent consideration. Also includes integration, transaction and certain other costs associated with acquisitions and divestitures, as well as amortization of intangible assets related to collaborations and licensing arrangements.

5 Includes the estimated tax impacts on the reconciling items based on applying the statutory rate of the originating territory of the non-GAAP adjustments for both periods presented. Amount in the second quarter of 2025 also includes a $146 million benefit primarily resulting from favorable audit adjustments. Amount in the second quarter of 2024 also includes a $259 million benefit due to a reduction in reserves for unrecognized income tax benefits resulting from the expiration of the statute of limitations for assessments related to the 2019 federal tax return year.

MERCK & CO., INC., RAHWAY, N.J., USA
CONSOLIDATED STATEMENT OF INCOME – GAAP
(AMOUNTS IN MILLIONS, EXCEPT PER SHARE FIGURES)
(UNAUDITED)
Table 1
                     
   

GAAP

 

% Change

 

GAAP

 

% Change

   

 

 

 

   

2Q25

2Q24

 

 

June YTD
2025

June YTD
2024

 

   

 

 

 

                     
Sales  

$

15,806

 

$

16,112

 

 

-2%

 

$

31,335

 

$

31,887

 

 

-2%

         

 

       

 

Costs, Expenses and Other        

 

       

 

Cost of sales  

 

3,557

 

 

3,745

 

 

-5%

 

 

6,976

 

 

7,285

 

 

-4%

Selling, general and administrative  

 

2,649

 

 

2,739

 

 

-3%

 

 

5,202

 

 

5,221

 

 

0%

Research and development  

 

4,048

 

 

3,500

 

 

16%

 

 

7,669

 

 

7,492

 

 

2%

Restructuring costs  

 

560

 

 

80

 

 

*

 

 

629

 

 

202

 

 

*

Other (income) expense, net  

 

(7

)

 

42

 

 

*

 

 

(43

)

 

12

 

 

*

Income Before Taxes  

 

4,999

 

 

6,006

 

 

-17%

 

 

10,902

 

 

11,675

 

 

-7%

Income Tax Provision  

 

571

 

 

545

 

 

 

 

 

1,388

 

 

1,447

 

 

 

Net Income  

 

4,428

 

 

5,461

 

 

-19%

 

 

9,514

 

 

10,228

 

 

-7%

Less: Net Income Attributable to Noncontrolling Interests  

 

1

 

 

6

 

 

 

 

 

8

 

 

11

 

 

 

Net Income Attributable to Merck & Co., Inc., Rahway, N.J., USA  

$

4,427

 

$

5,455

 

 

-19%

 

$

9,506

 

$

10,217

 

 

-7%

         

 

       

 

Earnings per Common Share Assuming Dilution  

$

1.76

 

$

2.14

 

 

-18%

 

$

3.77

 

$

4.02

 

 

-6%

                     
Average Shares Outstanding Assuming Dilution  

 

2,513

 

 

2,544

 

     

 

2,522

 

 

2,544

 

   
Tax Rate  

 

11.4

%

 

9.1

%

     

 

12.7

%

 

12.4

%

   
                     
* 100% or greater                    
MERCK & CO., INC., RAHWAY, N.J., USA
THREE AND SIX MONTHS ENDED JUNE 30, 2025 GAAP TO NON-GAAP RECONCILIATION
(AMOUNTS IN MILLIONS, EXCEPT PER SHARE FIGURES)
(UNAUDITED)
Table 2a
 
    GAAP   Acquisition- and Divestiture-Related Costs(1)   Restructuring Costs(2)   (Income) Loss from Investments in Equity Securities   Certain Other Items   Adjustment Subtotal   Non-GAAP
               
Second Quarter                            
Cost of sales  

$

3,557

 

 

576

 

 

165

 

         

741

 

 

$

2,816

 

Selling, general and administrative  

 

2,649

 

 

15

 

 

1

 

         

16

 

 

 

2,633

 

Research and development  

 

4,048

 

 

3

 

 

53

 

         

56

 

 

 

3,992

 

Restructuring costs  

 

560

 

     

560

 

         

560

 

 

 

 

Other (income) expense, net  

 

(7

)

         

(61

)

     

(61

)

 

 

54

 

Income Before Taxes  

 

4,999

 

 

(594

)

 

(779

)

 

61

 

     

(1,312

)

 

 

6,311

 

Income Tax Provision (Benefit)  

 

571

 

 

(102

)

(3)

(139

)

(3)

14

 

(3)

(146

)

(4)

(373

)

 

 

944

 

Net Income  

 

4,428

 

 

(492

)

 

(640

)

 

47

 

 

146

 

 

(939

)

 

 

5,367

 

Net Income Attributable to Merck & Co., Inc., Rahway, N.J., USA  

 

4,427

 

 

(492

)

 

(640

)

 

47

 

 

146

 

 

(939

)

 

 

5,366

 

Earnings per Common Share Assuming Dilution  

$

1.76

 

 

(0.20

)

 

(0.25

)

 

0.02

 

 

0.06

 

 

(0.37

)

 

$

2.13

 

                             
Tax Rate  

 

11.4

%

                     

 

15.0

%

                             
June YTD                            
Cost of sales  

$

6,976

 

 

1,196

 

 

201

 

         

1,397

 

 

$

5,579

 

Selling, general and administrative  

 

5,202

 

 

38

 

 

1

 

         

39

 

 

 

5,163

 

Research and development  

 

7,669

 

 

10

 

 

53

 

         

63

 

 

 

7,606

 

Restructuring costs  

 

629

 

     

629

 

         

629

 

 

 

 

Other (income) expense, net  

 

(43

)

 

(3

)

     

(168

)

     

(171

)

 

 

128

 

Income Before Taxes  

 

10,902

 

 

(1,241

)

 

(884

)

 

168

 

     

(1,957

)

 

 

12,859

 

Income Tax Provision (Benefit)  

 

1,388

 

 

(219

)

(3)

(157

)

(3)

36

 

(3)

(146

)

(4)

(486

)

 

 

1,874

 

Net Income  

 

9,514

 

 

(1,022

)

 

(727

)

 

132

 

 

146

 

 

(1,471

)

 

 

10,985

 

Net Income Attributable to Merck & Co., Inc., Rahway, N.J., USA  

 

9,506

 

 

(1,022

)

 

(727

)

 

132

 

 

146

 

 

(1,471

)

 

 

10,977

 

Earnings per Common Share Assuming Dilution  

$

3.77

 

 

(0.40

)

 

(0.29

)

 

0.05

 

 

0.06

 

 

(0.58

)

 

$

4.35

 

                             
Tax Rate  

 

12.7

%

                     

 

14.6

%

                             
Only the line items that are affected by non-GAAP adjustments are shown.
 
The Company is providing certain non-GAAP information that excludes certain items because of the nature of these items and the impact they have on the analysis of underlying business performance and trends. Management believes that providing non-GAAP information enhances investors’ understanding of the Company’s results because management uses non-GAAP measures to assess performance. Management uses non-GAAP measures internally for planning and forecasting purposes and to measure the performance of the Company along with other metrics. In addition, annual employee compensation, including senior management’s compensation, is derived in part using a non-GAAP pretax income metric. The non-GAAP information presented should be considered in addition to, but not as a substitute for or superior to, information prepared in accordance with GAAP.
 
(1) Amounts included in cost of sales reflect expenses for the amortization of intangible assets and intangible asset impairment charges, partially offset by a decrease in the estimated fair value measurement of liabilities for contingent consideration. Amounts included in selling, general and administrative expenses reflect integration, transaction and certain other costs related to acquisitions and divestitures. Amounts included in research and development expenses reflect the amortization of intangible assets.
 
(2) Amounts primarily include employee separation costs, accelerated depreciation and asset impairments associated with facilities to be closed or divested related to activities under the Company’s formal restructuring programs.
 
(3)Represents the estimated tax impacts on the reconciling items based on applying the statutory rate of the originating territory of the non-GAAP adjustments.
     
(4)Represents tax benefits primarily resulting from favorable audit adjustments.
MERCK & CO., INC., RAHWAY, N.J., USA
FRANCHISE / KEY PRODUCT SALES
(AMOUNTS IN MILLIONS)
(UNAUDITED)
Table 3
                                 
 

2025

 

2024

 

2Q

 

June YTD

 

1Q

2Q

June YTD

 

1Q

2Q

June YTD

3Q

4Q

Full Year

 

Nom %

Ex-Exch %

 

Nom %

Ex-Exch %

TOTAL SALES(1)

$15,529

$15,806

$31,335

 

$15,775

$16,112

$31,887

$16,657

$15,624

$64,168

 

-2

-2

 

-2

0

PHARMACEUTICAL

13,638

14,050

27,688

 

14,006

14,408

28,415

14,943

14,042

57,400

 

-2

-3

 

-3

-2

Oncology                                
Keytruda

7,205

7,956

15,161

 

6,947

7,270

14,217

7,429

7,836

29,482

 

9

9

 

7

8

Alliance Revenue – Lynparza (2)

312

370

682

 

292

317

609

337

365

1,311

 

17

15

 

12

12

Alliance Revenue – Lenvima(2)

258

265

523

 

255

249

504

251

255

1,010

 

6

5

 

4

4

Welireg

137

162

300

 

85

126

211

139

160

509

 

29

29

 

42

43

Alliance Revenue – Reblozyl(3)

119

107

226

 

71

90

161

100

110

371

 

19

19

 

40

40

Vaccines(4)                                
Gardasil/Gardasil 9

1,327

1,126

2,453

 

2,249

2,478

4,727

2,306

1,550

8,583

 

-55

-55

 

-48

-48

ProQuad/M-M-R II/Varivax

539

609

1,148

 

570

617

1,187

703

594

2,485

 

-1

-2

 

-3

-3

Vaxneuvance

230

229

459

 

219

189

408

239

161

808

 

21

20

 

13

13

RotaTeq

228

121

349

 

216

163

379

193

139

711

 

-26

-26

 

-8

-7

Capvaxive

107

129

236

       

47

50

97

 

 

Pneumovax 23

41

38

79

 

61

59

120

68

74

263

 

-36

-37

 

-35

-33

Hospital Acute Care                                
Bridion

441

461

902

 

440

455

895

420

449

1,764

 

1

1

 

1

1

Prevymis

208

228

436

 

174

188

362

208

215

785

 

21

20

 

20

21

Dificid

83

96

179

 

73

92

165

96

79

340

 

5

5

 

8

9

Zerbaxa

70

74

145

 

56

62

118

64

70

252

 

21

21

 

23

24

Cardiovascular                                
Winrevair

280

336

615

   

70

70

149

200

419

  * *   * *
Alliance Revenue – Adempas/Verquvo(5)

106

123

229

 

98

106

203

102

109

415

 

16

16

 

12

12

Adempas(6)

68

80

147

 

70

72

142

72

73

287

 

10

6

 

4

4

Virology                                
Lagevrio

102

83

185

 

350

110

460

383

121

964

 

-25

-27

 

-60

-59

Isentress/Isentress HD

90

86

176

 

111

89

200

102

92

394

 

-3

-4

 

-12

-11

Delstrigo

67

83

150

 

56

60

116

65

69

249

 

40

35

 

30

30

Pifeltro

45

41

86

 

42

39

81

42

40

163

 

5

4

 

6

6

Neuroscience                                
Belsomra

50

40

90

 

46

53

99

78

45

222

 

-24

-26

 

-9

-8

Immunology                                
Simponi        

184

172

356

189

 

543

 

-100

-100

 

-100

-100

Remicade        

39

35

74

41

 

114

 

-100

-100

 

-100

-100

Diabetes (7)                                
Januvia

549

372

921

 

419

405

824

278

232

1,334

 

-8

-8

 

12

13

Janumet

247

251

498

 

251

224

475

204

255

935

 

12

14

 

5

8

Other Pharmaceutical(8)

729

584

1,313

 

632

618

1,252

638

699

2,590

 

-6

-7

 

5

6

ANIMAL HEALTH

1,588

1,646

3,234

 

1,511

1,482

2,993

1,487

1,397

5,877

 

11

11

 

8

11

Livestock

924

961

1,885

 

850

837

1,686

886

889

3,462

 

15

16

 

12

16

Companion Animal

664

685

1,349

 

661

645

1,307

601

508

2,415

 

6

6

 

3

4

Other Revenues(9)

303

110

413

 

258

222

479

227

185

891

 

-50

-3

 

-14

7

                                 
*200% or greater
Sum of quarterly amounts may not equal year-to-date amounts due to rounding.
(1)Only select products are shown.
(2)Alliance Revenue represents the Company’s share of profits, which are product sales net of cost of sales and commercialization costs.
(3)Alliance Revenue represents royalties.
(4)Total Vaccines sales were $2,607 million and $2,370 million in the first and second quarter of 2025, respectively, and $3,424 million and $3,656 million in the first and second quarter of 2024, respectively.
(5)Alliance Revenue represents the Company’s share of profits from sales in Bayer’s marketing territories, which are product sales net of cost of sales and commercialization costs.
(6)Net product sales in the Company’s marketing territories.
(7)Total Diabetes sales were $876 million and $704 million in the first and second quarter of 2025, respectively, and $745 million and $715 million in the first and second quarter of 2024.
(8)Includes Pharmaceutical products not individually shown above.
(9)Other Revenues are comprised primarily of revenues from third-party manufacturing arrangements and miscellaneous corporate revenues, including revenue-hedging activities. Other Revenues related to the receipt of upfront and milestone payments for out-licensed products were $95 million and $5 million in the first and second quarter of 2025, respectively, and $61 million and $15 million in the first and second quarter of 2024, respectively.

 

Media Contacts:

Michael Levey
michael.levey@msd.com

Johanna Herrmann
johanna.herrmann@msd.com

Investor Contacts:

Peter Dannenbaum
(732) 594-1579

Steven Graziano
(732) 594-1583

Source: Merck & Co., Inc.


Merck (NYSE: MRK), known as MSD outside of the United States and Canada, announced today that the Board of Directors has declared a quarterly dividend of $0.81 per share of the company’s common stock for the fourth quarter of 2025. Payment will be made on Oct. 7, 2025 to shareholders of record at the close of business on Sept. 15, 2025.

About Merck

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA

This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).


Media Contacts:

John Cummins

john.cummins2@merck.com

Michael Levey

michael.levey@merck.com

Investor Contacts:

Peter Dannenbaum

(732) 594-1579

Steven Graziano

(732) 594-1583

Source: Merck & Co., Inc.

In collaboration with the Gates Foundation, Merck advances MK-8527 pre-exposure prophylaxis (PrEP) clinical trials globally

Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the initiation of the EXPrESSIVE Phase 3 clinical trials, evaluating the safety and efficacy of MK-8527, an investigational once-monthly, oral nucleoside reverse transcriptase translocation inhibitor (NRTTI) for HIV pre-exposure prophylaxis (PrEP). The EXPrESSIVE-11 (MK-8527-011, NCT 07044297) trial will evaluate the safety and efficacy of MK-8527 among people with greater likelihood of HIV-1 exposure in 16 countries and will begin enrolling in August 2025. In collaboration with the Gates Foundation, the EXPrESSIVE-10 (MK-8527-010) trial will evaluate the safety and efficacy of MK-8527 in women and adolescent girls in sub-Saharan Africa and will begin enrolling in the next few months.

“According to UNAIDS, 1.3 million people acquired HIV in 2023, highlighting the continued need for new PrEP options like our investigational once-monthly, oral PrEP candidate MK-8527, especially among women in sub-Saharan Africa and men who have sex with men, who experience disproportionately high rates of HIV,” said Dr. Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories. “Our collaboration with the Gates Foundation will help us explore the potential of MK-8527 to contribute to global efforts to reduce the number of HIV infections and help support opportunities to accelerate access around the world.”

The decision to initiate the Phase 3 clinical trial program was supported by the results of a double-blind, multicenter, Phase 2 trial (MK-8527-007, NCT 06045507) examining the safety and pharmacokinetics of MK-8527. The study enrolled 350 participants, 18–65 years of age, with low likelihood of HIV-1 exposure, who were randomized 2:2:2:1 to receive MK-8527 (3, 6, or 12 mg) or placebo once monthly for six months. In the trial, the rates of adverse events were similar among those in the MK-8527 arms and those in the placebo arm, and no clinically meaningful changes were seen in laboratory tests, including total lymphocyte and CD4 T-cell counts. The pharmacokinetics of MK-8527 and MK-8527-TP, the active form of MK-8527, support the continued development of MK-8527 as an oral, once-monthly option for PrEP. Results from the Phase 2 trial were highlighted in the opening press conference for IAS 2025, the 13th International AIDS Society Conference on HIV Science in Kigali, Rwanda, on Monday, July 14, at 15:30 – 16:30 CAT, titled “Breakthroughs Amid Crisis: The Future of HIV Innovation.” These research findings will be further detailed in a late-breaker oral session on Wednesday, July 16, at 12:15 – 13:15 CAT.

“Scientific advances against HIV have brought us further than ever imagined and are ushering in a new era in HIV prevention,” said Trevor Mundel, president of global health at the Gates Foundation. “With only 18% of global PrEP need currently met, there is a clear and urgent need for options like MK-8527 that may offer the ability to prevent infection. These Phase 3 trials are a key step toward translating progress into longer-acting options that could help turn the tide on HIV.”

In the EXPrESSIVE-10 trial, the International Clinical Research Center (ICRC) within the University of Washington Department of Global Health, in partnership with the University of Alabama at Birmingham, will receive grant funding from the Gates Foundation to support ICRC’s collaboration with 31 clinical research trial sites in Kenya, South Africa, and Uganda; sites will inform and engage communities and recruit, enroll, and follow women who participate in the EXPrESSIVE-10 trial. Merck will be the trial sponsor, gaining regulatory and customs approvals, and providing operational expertise and resources for management of the trials. The Gates Foundation will also provide support for global community advisory groups, which will offer insight into community perspectives on a monthly PrEP pill, participant recruitment materials and strategies, and cultural considerations for these trials. Separately, the Gates Foundation will provide grant funding for EXPrESSIVE-11 to support the establishment of a community advisory group and the development of recruiting and retention materials only.

About the EXPrESSIVE MK-8527 Phase 3 Clinical Trial Program

The EXPrESSIVE-11 trial (MK-8527-011, NCT 07044297) is a randomized, active-controlled study enrolling 4,390 sexually active people who could benefit from PrEP across trial sites in 16 countries. The primary objective of the study is to evaluate the efficacy, safety, and tolerability of once-monthly oral MK-8527 compared to daily emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) as assessed by the incidence rate per year of adjudicated HIV-1 infections. The trial will begin enrolling in August 2025.

The EXPrESSIVE-10 trial (MK-8527-010) is a randomized, active-controlled study enrolling 4,580 sexually active women aged 16 to 30 in Kenya, South Africa, and Uganda. The primary objective of the study is to evaluate the efficacy, safety, and tolerability of once-monthly oral MK-8527 compared to daily emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) as assessed by the incidence rate per year of adjudicated HIV-1 infections. The study will begin enrolling in the next few months.

About MK-8527

MK-8527 is being evaluated as a potential once-monthly oral prevention option for HIV-1. MK-8527 inhibits reverse transcriptase through multiple mechanisms of action, including inhibition of translocation and delayed chain termination. For an overview of Merck’s complete HIV treatment and prevention clinical development program, please click here.

Merck’s Commitment to HIV

For more than 35 years, Merck has been committed to scientific research and discovery in HIV, leading to scientific breakthroughs that have helped change HIV treatment. Our work has helped pioneer the development of new options across multiple drug classes to help those impacted by HIV. Today, we are developing a series of antiviral options designed to help people manage their HIV and to help prevent HIV, with the goal of reducing the growing burden of HIV worldwide. We want to ensure people are not defined by HIV, and our work focuses on transformational innovations, collaborations with others in the global HIV community, and access initiatives aimed at helping to end the HIV epidemic for everyone.

About Merck

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable, and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube, and LinkedIn.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA

This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

Media:
Julie Cunningham
(617) 519-6264

Deb Wambold
(215) 779-2234

Investor:
Peter Dannenbaum
(732) 594-1579

Steven Graziano
(732) 594-1583

Source: Merck & Co., Inc.

12-Month Parasiticide Treatment for Dogs Offers Unrivaled Duration of Flea and Tick Protection Compared to Existing Products

RAHWAY, N.J., July 10, 2025 – Merck Animal Health, known as MSD Animal Health outside of the United States and Canada, a division of Merck & Co., Inc., Rahway, N.J., USA (NYSE:MRK), today announced the U.S. Food and Drug Administration (FDA) approval of BRAVECTO® QUANTUM (fluralaner for extended-release injectable suspension) – a new, once-yearly1 injectable product to treat and protect dogs from fleas and ticks. The product is expected to be available at veterinary clinics and hospitals nationwide by August 2025.

BRAVECTO QUANTUM was first approved in Australia and New Zealand in 2023, followed by the European Union (EU) in 2024 and now the U.S. in 2025. In total, BRAVECTO QUANTUM is currently approved in more than 50 countries worldwide.

“We take great pride in our company’s leadership in long-acting preventative parasiticides and are excited to offer a convenient option that gives dogs year-round1 comprehensive protection from fleas and ticks in one easy injection they can receive from their veterinarian,” said Christine Royal, DVM, vice president, companion animal and equine business unit, Merck Animal Health. “The approval of BRAVECTO QUANTUM sets a new standard in pet care by providing veterinarians and pet parents with a safe and effective option when it comes to flea and tick protection for dogs.”

BRAVECTO QUANTUM kills adult fleas and is indicated for the treatment and prevention of flea infestations (Ctenocephalides felis) and for the treatment and control of tick infestations – Ixodes scapularis (black-legged tick), Dermacentor variabilis (American dog tick) and Rhipicephalus sanguineus (brown dog tick) for 12 months in dogs and puppies 6 months of age and older. BRAVECTO QUANTUM is also indicated for the treatment and control of Amblyomma americanum (lone star tick) infestations for 8 months in dogs and puppies 6 months of age and older.

BRAVECTO QUANTUM is the first and only parasiticide that protects against fleas and ticks for an entire year with a single dose, offering longer flea and tick protection than any other systemic product currently on the market.

“Though people often think of flea and tick season during the summer months, studies have shown that while fleas and ticks are most active from early spring through the fall, they can be a threat year-round, especially knowing it only takes a few warm days for ticks to become active,” said Frank Guerino, Ph.D., associate vice president of Global Pharmaceutical Development, Merck Animal Health. “With BRAVECTO QUANTUM, a single dose provides year-long, continuous protection, simplifying care for both pet owners and veterinarians, and promoting compliance.”

BRAVECTO QUANTUM utilizes a unique, patented composition of fluralaner that allows effective levels to be maintained for as long as 12 months. Fleas and ticks are a nuisance and pose serious risk to both animal and human health as they can transmit serious diseases. Fleas can also cause severe allergic dermatitis in dogs and cats. Many fleas and ticks can live in both warm and cold temperatures, making continuous year-round protection of utmost importance for pets and people.

BRAVECTO QUANTUM exemplifies Merck Animal Health’s commitment to groundbreaking science and has been recognized as a winner of the 2024 Edison Awards and the 2024 S&P Global Awards for Best New Companion Animal Product. For more information, visit us.bravecto.com or follow BRAVECTO on Instagram @bravecto.us

1 BRAVECTO® QUANTUM is indicated to protect against Amblyomma americanum for 8 months.

About BRAVECTO®

Since its introduction in 2014, BRAVECTO has provided longer-lasting flea and tick protection, with more than 350 million doses distributed in 100 countries over eight years. BRAVECTO is available in a variety of formulations, including products for both dogs and cats.

The flea lifecycle can last as long as 12 weeks, and monthly treatments may leave gaps in protection. Providing pets with continuous flea and tick protection is essential – whether the pet goes outside or not. Contrary to popular belief among pet owners, fleas and ticks are not only active in the spring and summer months and are a year-round risk. Fleas and ticks can easily latch onto dogs and cats and can spread serious diseases. Fleas are the most common external parasite found on pets. BRAVECTO products are only available through licensed veterinarians.

Important Safety Information

BRAVECTO QUANTUM: indicated for the treatment and prevention of flea infestations (Ctenocephalides felis) and for the treatment and control of tick infestations [Ixodes scapularis (black-legged tick), Dermacentor variabilis (American dog tick) and Rhipicephalus sanguineus (brown dog tick)] for 12 months in dogs and puppies 6 months of age and older. BRAVECTO QUANTUM is also indicated for the treatment and control of Amblyomma americanum (lone star tick) infestations for 8 months in dogs and puppies 6 months of age and older. BRAVECTO QUANTUM (fluralaner for extended-release injectable suspension) for Dogs: The most commonly reported adverse reactions in a US field study included lethargy, decreased appetite, vomiting, diarrhea, elevated liver enzymes and pruritus. BRAVECTO QUANTUM is not effective against lone star ticks beyond 8 months of dosing. Fluralaner is a member of the isoxazoline class. This class has been associated with neurologic adverse reactions including tremors, ataxia, and seizures. Seizures have been reported in dogs receiving isoxazoline class drugs, even in dogs without a history of seizures. Use with caution in dogs with a history of seizures or neurologic disorders. The safety of BRAVECTO QUANTUM has not been evaluated in breeding, pregnant and lactating dogs. In some cases, adverse events have been reported following use of BRAVECTO (fluralaner) Chews in breeding females. For use in dogs and puppies 6 months of age and older.

BRAVECTO 1-MONTH Chews: indicated for dogs 8 weeks of age and older. The most commonly reported adverse reactions include itching, diarrhea, vomiting, decreased appetite, elevated ALT, lethargy, and weight loss. BRAVECTO 1-MONTH is not effective against A. americanum in puppies less than 6 months of age. BRAVECTO Chews for Dogs: The most commonly reported adverse reactions include vomiting, lethargy, diarrhea, anorexia and pruritus. In some cases, adverse events have been reported following use in breeding females. BRAVECTO Topical Solution for Dogs: The most commonly reported adverse reactions include vomiting, hair loss, diarrhea, lethargy, decreased appetite, and moist dermatitis/rash. BRAVECTO Topical Solution for Cats: The most commonly reported adverse reactions include vomiting, itching, diarrhea, hair loss, decreased appetite, lethargy, and scabs/ulcerated lesions. BRAVECTO Topical Solution for Cats is not effective against American dog ticks beyond 8 weeks of dosing. BRAVECTO PLUS Topical Solution for Cats: The most commonly reported adverse reactions include vomiting, hair loss, itching, diarrhea, lethargy, dry skin, elevated ALT, and hypersalivation. BRAVECTO PLUS has not been shown to be effective for 2 months in kittens less than 6 months of age. Use with caution in cats that are heartworm positive. The effectiveness of BRAVECTO PLUS to prevent heartworm disease after bathing or water immersion has not been evaluated.

BRAVECTO has not been shown to be effective for 12-weeks’ duration in puppies or kittens less than 6 months of age. BRAVECTO Chews and Topical Solution for dogs is not effective against the lone star tick beyond 8 weeks of dosing. BRAVECTO Topical Solution for Dogs and Cats and BRAVECTO PLUS for cats are for topical use only. Avoid oral ingestion.

The safety of BRAVECTO Topical Solution for Cats and BRAVECTO PLUS has not been established in breeding, pregnant, and lactating cats.

All BRAVECTO products contain fluralaner, which is a member of the isoxazoline class. This class has been associated with neurologic adverse reactions including tremors, ataxia, and seizures. Seizures have been reported in dogs receiving isoxazoline class drugs, even in dogs without a history of seizures. Use with caution in dogs with a history of seizures or neurologic disorders. Neurologic adverse reactions have been reported in cats receiving isoxazoline class drugs, even in cats without a history of neurologic disorders. Use with caution in cats with a history of neurologic disorders.

About Merck Animal Health

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than a century, we’ve been at the forefront of research, bringing forward medicines, vaccines and innovative health solutions for the world’s most challenging diseases. Merck Animal Health, a division of Merck & Co., Inc., Rahway, N.J., USA, is the global animal health business of Merck. Through its commitment to The Science of Healthier Animals®, Merck Animal Health offers veterinarians, farmers, producers, pet owners and governments one of the widest ranges of veterinary pharmaceuticals, vaccines and health management solutions and services as well as an extensive suite of connected technology that includes identification, traceability and monitoring products. Merck Animal Health is dedicated to preserving and improving the health, well-being and performance of animals and the people who care for them. It invests extensively in dynamic and comprehensive R&D resources and a modern, global supply chain. Merck Animal Health is present in more than 50 countries, while its products are available in some 150 markets. For more information, visit www.merck-animal-health.com and connect with us on LinkedIn, Facebook, X (formerly Twitter) and Instagram.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA

This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

Media Contact:

Laurel Sawicki

(908) 872-9783

laurel.mundth@merck.com

Kim Gorode

(973) 255-9094

Kim.gorode@merck.com

Investor Inquiries:

Peter Dannenbaum

(908) 740-1037

peter.dannenbaum@merck.com

Doravirine/islatravir would be the first FDA-approved two-drug regimen without an integrase inhibitor that demonstrated non-inferior efficacy and a generally comparable safety profile to the three-drug InSTI-based regimen, BIC/FTC/TAF, in a Phase 3 pivotal trial

Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced that the U.S. Food and Drug Administration (FDA) has accepted for review the New Drug Application (NDA) for doravirine/islatravir (DOR/ISL), an investigational, once-daily, oral, two-drug regimen for adults with HIV-1 infection that is virologically suppressed on antiretroviral therapy. The FDA has set a target action date of April 28, 2026, for the application under the Prescription Drug User Fee Act (PDUFA).

“Merck has been at the forefront of HIV research for more than 35 years and we are pleased to continue our work to innovate and deliver new options that aim to meet the needs of the HIV community,” said Dr. Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories. “The health needs of people living with HIV often change over time – whether it’s managing comorbidities or navigating complex medication regimens. We believe DOR/ISL, if approved, will represent an important new complete regimen option designed to help meet their diverse needs.”

The NDA is based on findings at Week 48 of two pivotal Phase 3 clinical trials (MK-8591A-051 and MK-8591A-052) where DOR/ISL was demonstrated to be non-inferior to baseline antiretroviral therapy (bART) in the open-label trial MK-8591A-051 and non-inferior to bictegravir/emtrictabine/tenofovir alafenamidei [BIC/FTC/TAF (50mg/200mg/25mg)] in the double-blind trial MK-8591A-052. Across both trials, the safety profile of DOR/ISL was generally comparable to comparator baseline antiretroviral regimens in trial MK-8591A-051 and BIC/FTC/TAF in trial MK-8591A-052. Data from these trials were presented during the 2025 Conference on Retroviruses and Opportunistic Infections (CROI) in San Francisco.

About the Phase 3 Trial MK-8591A-051
MK-8591A-051 is a Phase 3, open-label, randomized, active-controlled clinical trial evaluating the efficacy and safety of a switch to investigational, oral, once-daily DOR/ISL (100mg/0.25mg) in adults with HIV-1 infection that has been virologically suppressed using ART. The primary efficacy endpoint was the percentage of participants with HIV-1 RNA ≥50 copies/mL at Week 48 (non-inferiority margin 4%). In this trial, 551 adults with HIV-1 RNA <50 copies/mL for three months or more on oral 2- or 3-drug ART, with no history of treatment failure and no known virologic resistance to DOR, were randomized 2:1 and switched to DOR/ISL (n=366) or continued bART (n=185), stratified by bART regimen. The median age of participants was 51 years; 39.7% were assigned female sex at birth, 45.4% were Black or African American, and 14.5% were Hispanic or Latine. At baseline, 64.2% were treated with an InSTI-based regimen, 30.3% with an NNRTI-based regimen, and 5.4% with a protease inhibitor (PI)-based regimen, with median duration on current ART of 3.8 years (IQR 2.0-6.3).

About the Phase 3 Trial MK-8591A-052
MK-8591A-052 is a Phase 3, double-blind, randomized, active-controlled clinical trial to evaluate the efficacy and safety of a switch to investigational, oral, once-daily DOR/ISL (100mg/0.25mg) in adults with HIV-1 infection that has been virologically suppressed on BIC/FTC/TAF (50mg/200mg/25mg). The primary efficacy endpoint was the percentage of participants with HIV-1 RNA ≥50 copies/mL at Week 48 (non-inferiority margin 4%). In this trial, 513 adults with HIV-1 who had virologic suppression for three months or more on BIC/FTC/TAF, no history of treatment failure and no known resistance to DOR were randomized (2:1) and switched to DOR/ISL (n=342) or continued treatment with BIC/FTC/TAF (n=171). The median age of participants was 47 years; 21.4% were assigned female sex at birth, 30.8% were Black or African American, and 22.8% were Hispanic or Latine. The median duration of BIC/FTC/TAF treatment prior to trial enrollment was 3.4 years (IQR 2.0-5.0).

About Islatravir (MK-8591) and Merck’s HIV Research
Islatravir (MK-8591), Merck’s investigational nucleoside reverse transcriptase translocation inhibitor (NRTTI), blocks HIV-1 replication by multiple mechanisms including inhibition of reverse transcriptase translocation, resulting in immediate chain termination and induction of structural changes in the viral DNA, resulting in delayed chain termination. Islatravir is under evaluation in multiple ongoing early and late-stage clinical trials in combination with other antiretrovirals for potential daily and once-weekly treatments for HIV-1, with islatravir serving as the anchor medicine in the treatment regimens based on its potency and resistance profile. In addition to the MK-8591A-051 and MK-8591A-052 trials, ongoing Phase 3 trials of daily DOR/ISL (100mg /0.25mg) include MK-8591A-053 in people with HIV who had not previously received treatment (treatment-naïve), and MK-8591A-054 evaluating open-label DOR/ISL (100 mg/0.25 mg) in individuals who participated in earlier Phase 3 trials of DOR/ISL (100 mg/0.75 mg). Islatravir in combination with Gilead’s lenacapavir is in Phase 3 development as a novel oral once-weekly treatment for HIV-1, and islatravir in combination with our company’s investigational non-nucleoside reverse transcriptase inhibitor (NNRTI) ulonivirine (MK-8507) is in Phase 2 development as an oral once-weekly treatment.

Merck’s commitment to researching NRTTIs includes MK-8527, an investigational, novel oral, once-monthly NRTTI candidate that is in Phase 2 development for HIV-1 pre-exposure prophylaxis (PrEP). For an overview of Merck’s HIV treatment and prevention clinical development program, please click here.

Merck’s Commitment to HIV
For more than 35 years, Merck has been committed to scientific research and discovery in HIV leading to scientific breakthroughs that have helped change HIV treatment. Our work has helped pioneer the development of new options across multiple drug classes to help those impacted by HIV. Today, we are developing a series of antiviral options designed to help people manage their HIV and to help prevent HIV, with the goal of reducing the growing burden of infection worldwide. We want to ensure people are not defined by HIV, and our work focuses on transformational innovations, collaborations with others in the global HIV community, and access initiatives aimed at helping to end the HIV epidemic for everyone.

Indications and usage for PIFELTRO® (doravirine) and DELSTRIGO® (doravirine, lamivudine, and tenofovir disoproxil fumarate) in the U.S.
PIFELTRO is indicated in combination with other antiretroviral (ARV) agents for the treatment of HIV-1 infection in adult patients with no prior ARV treatment history or to replace the current ARV regimen in those who are virologically suppressed (HIV-1 RNA less than 50 copies per mL) on a stable ARV regimen with no history of treatment failure and no known substitutions associated with resistance to doravirine.

DELSTRIGO is indicated as a complete regimen for the treatment of HIV-1 infection in adult patients with no prior ARV treatment history or to replace the current ARV regimen in those who are virologically suppressed (HIV-1 RNA less than 50 copies per mL) on a stable ARV regimen with no history of treatment failure and no known substitutions associated with resistance to the individual components of DELSTRIGO.

Selected Safety Information

Warning: Posttreatment Acute Exacerbation of Hepatitis B Virus (HBV) for DELSTRIGO
All patients with HIV-1 should be tested for the presence of HBV before initiating ARV therapy. Severe acute exacerbations of HBV have been reported in people with concomitant HIV-1 and HBV who have discontinued products containing lamivudine or tenofovir disoproxil fumarate (TDF), which are components of DELSTRIGO. Patients coinfected with HIV-1 and HBV who discontinue DELSTRIGO should be monitored with both clinical and laboratory follow-up for at least several months after stopping DELSTRIGO. If appropriate, initiation of anti-HBV therapy may be warranted.

Contraindications
PIFELTRO and DELSTRIGO are contraindicated when coadministered with drugs that are strong cytochrome P450 (CYP)3A enzyme inducers (including the anticonvulsants carbamazepine, oxcarbazepine, phenobarbital, and phenytoin; the androgen receptor inhibitor enzalutamide; the antimycobacterials rifampin and rifapentine; the cytotoxic agent mitotane; and the herbal product St. John’s wort (Hypericum perforatum)), as significant decreases in doravirine plasma concentrations may occur, which may decrease the effectiveness of DELSTRIGO and PIFELTRO.

DELSTRIGO is contraindicated in patients with a previous hypersensitivity reaction to lamivudine.

Warnings and Precautions
Severe Skin Reactions
Severe skin reactions, including Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN), have been reported during the postmarketing experience with doravirine-containing regimens. Discontinue PIFELTRO or DELSTRIGO, and other medications known to be associated with severe skin reactions, immediately if a painful rash with mucosal involvement or a progressive severe rash develops. Clinical status should be closely monitored, and appropriate therapy should be initiated.

New or Worsening Renal Impairment
Renal impairment, including cases of acute renal failure and Fanconi syndrome, have been reported with the use of TDF. DELSTRIGO should be avoided with concurrent or recent use of a nephrotoxic agent (eg, high-dose or multiple NSAIDs). Cases of acute renal failure after initiation of high-dose or multiple NSAIDs have been reported in people living with HIV with risk factors for renal dysfunction who appeared stable on TDF.

Prior to or when initiating DELSTRIGO, and during treatment, assess serum creatinine, estimated creatinine clearance, urine glucose, and urine protein in all patients. In patients with chronic kidney disease, also assess serum phosphorus. Discontinue DELSTRIGO in patients who develop clinically significant decreases in renal function or evidence of Fanconi syndrome. Discontinue DELSTRIGO if estimated creatinine clearance declines below 50 mL/min.

Bone Loss and Mineralization Defects
In clinical trials in adults living with HIV, TDF was associated with slightly greater decreases in bone mineral density (BMD) and increases in biochemical markers of bone metabolism. Serum parathyroid hormone levels and 1,25 Vitamin D levels were also higher. Cases of osteomalacia associated with proximal renal tubulopathy have been reported with the use of TDF. The effects of TDF-associated changes in BMD and biochemical markers on long-term bone health and future fracture risk in adults are unknown.

Immune Reconstitution Syndrome
Immune reconstitution syndrome can occur, including the occurrence of autoimmune disorders with variable time to onset, which may necessitate further evaluation and treatment.

Drug Interactions
Because DELSTRIGO is a complete regimen, coadministration with other antiretroviral medications for the treatment of HIV-1 infection is not recommended.

Coadministration of PIFELTRO with efavirenz, etravirine, or nevirapine is not recommended.

If DELSTRIGO is coadministered with rifabutin, take one tablet of DELSTRIGO once daily, followed by one tablet of doravirine (PIFELTRO) approximately 12 hours after the dose of DELSTRIGO.

If PIFELTRO is coadministered with rifabutin, increase PIFELTRO dosage to one tablet twice daily (approximately 12 hours apart).

Consult the full Prescribing Information prior to and during treatment for more information on potential drug-drug interactions.

Dosage and Administration/Specific Populations
Renal Impairment
Because DELSTRIGO is a fixed-dose combination tablet and the dosage of lamivudine and TDF cannot be adjusted, DELSTRIGO is not recommended in patients with estimated creatinine clearance less than 50 mL/min.

Adverse Reactions
The most common adverse reactions with DELSTRIGO (incidence ≥5%, all intensities) were dizziness (7%), nausea (5%), and abnormal dreams (5%). The most common adverse reactions with PIFELTRO (incidence ≥5%, all intensities) were nausea (7%), dizziness (7%), headache (6%), fatigue (6%), diarrhea (6%), abdominal pain (5%), and abnormal dreams (5%).

By week 96 in DRIVE-FORWARD, 2% of adult participants in the PIFELTRO group and 3% in the darunavir+ritonavir (DRV+r) group had adverse events leading to discontinuation of study medication.

By week 96 in DRIVE-AHEAD, 3% of adult participants in the DELSTRIGO group and 7% in the efavirenz (EFV)/emtricitabine (FTC)/TDF group had adverse events leading to discontinuation of study medication.

In DRIVE-FORWARD, mean changes from baseline at week 48 in LDL-cholesterol (LDL-C) and non-HDL-cholesterol (non-HDL-C) were pre-specified. LDL-C: -4.6 mg/dL in the PIFELTRO group vs 9.5 mg/dL in the DRV+r group. Non-HDL-C: -5.4 mg/dL in the PIFELTRO group vs 13.7 mg/dL in the DRV+r group. The clinical benefits of these findings have not been demonstrated.

In DRIVE-AHEAD, mean changes from baseline at week 48 in LDL-C and non-HDL-C were pre-specified. LDL-C: -2.1 mg/dL in the DELSTRIGO group vs 8.3 mg/dL in the EFV/FTC/TDF group. Non-HDL-C: -4.1 mg/dL in the DELSTRIGO group vs 12.7 mg/dL in the EFV/FTC/TDF group. The clinical benefits of these findings have not been demonstrated.

In DRIVE-SHIFT, mean changes from baseline at week 24 in LDL-C and non-HDL-C were pre-specified. LDL-C: -16.3 mg/dL in the DELSTRIGO group vs -2.6 mg/dL in the PI + ritonavir group. Non-HDL-C: -24.8 mg/dL in the DELSTRIGO group vs -2.1 mg/dL in the PI + ritonavir group. The clinical benefits of these findings have not been demonstrated.

In DRIVE-AHEAD, neuropsychiatric adverse events were reported in the three pre-specified categories of sleep disorders and disturbances, dizziness, and altered sensorium. Twelve percent of adult participants in the DELSTRIGO group and 26% in the EFV/FTC/TDF group reported neuropsychiatric adverse events of sleep disorders and disturbances; 9% in the DELSTRIGO group and 37% in the EFV/FTC/TDF group reported dizziness; and 4% in the DELSTRIGO group and 8% in the EFV/FTC/TDF group reported altered sensorium.

The safety of DELSTRIGO in virologically-suppressed adults was based on week 48 data from participants in the DRIVE-SHIFT trial. Overall, the safety profile in virologically-suppressed adult participants was similar to that in participants with no ARV treatment history.

Serum ALT and AST Elevations: In the DRIVE-SHIFT trial, 22% and 16% of participants in the immediate switch group experienced ALT and AST elevations greater than 1.25 X ULN, respectively, through 48 weeks on DELSTRIGO. For these ALT and AST elevations, no apparent patterns with regard to time to onset relative to switch were observed. One percent of participants had ALT or AST elevations greater than 5 X ULN through 48 weeks on DELSTRIGO. The ALT and AST elevations were generally asymptomatic, and not associated with bilirubin elevations. In comparison, 4% and 4% of participants in the delayed switch group experienced ALT and AST elevations of greater than 1.25 X ULN through 24 weeks on their baseline regimen.

Pregnancy/Breastfeeding
There is a pregnancy exposure registry that monitors pregnancy outcomes in individuals exposed to PIFELTRO or DELSTRIGO during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263.

Inform individuals with HIV-1 infection of the potential risks of breastfeeding, including: (1) HIV-1 transmission (in HIV-1–negative infants), (2) developing viral resistance (in HIV-1–positive infants), and (3) serious adverse reactions in a breastfed infant similar to those seen in adults.

About Merck
At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA
This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

Please see Prescribing Information for PIFELTRO (doravirine) at: https://www.merck.com/product/usa/pi_circulars/p/pifeltro/pifeltro_pi.pdf and Patient Information for PIFELTRO at: https://www.merck.com/product/usa/pi_circulars/p/pifeltro/pifeltro_ppi.pdf

Please see Prescribing Information for DELSTRIGO (doravirine, lamivudine, and tenofovir disoproxil fumarate) at: https://www.merck.com/product/usa/pi_circulars/d/delstrigo/delstrigo_pi.pdf and Patient Information for DELSTRIGO at: https://www.merck.

i bictegravir/emtricitabine/tenofovir alafenamide (BIKTARVY) is a registered trademark of Gilead Sciences, Inc.

 

Media Contacts:

Julie Cunningham
(617) 519-6264

Deb Wambold
(215) 779-2234

Investor Contacts:

Peter Dannenbaum
(732) 594-1579

Steven Graziano
(732) 594-1583

Source: Merck Sharp & Dohme

Acquisition aligns with Merck’s science-led business development strategy and expands pipeline and portfolio of treatments for cardio-pulmonary diseases

Merck to hold investor call at 8 a.m. ET today

Merck (NYSE: MRK), known as MSD outside of the United States and Canada, and Verona Pharma plc (Nasdaq: VRNA) (“Verona Pharma”), a biopharmaceutical company focused on respiratory diseases, today announced that the companies have entered into a definitive agreement under which Merck, through a subsidiary, will acquire Verona Pharma for $107 per American Depository Share (ADS), each of which represents eight Verona Pharma ordinary shares, for a total transaction value of approximately $10 billion.

Through this acquisition Merck will add Ohtuvayre® (ensifentrine), a first-in-class selective dual inhibitor of phosphodiesterase 3 and 4 (PDE3 and PDE4), to its growing cardio-pulmonary pipeline and portfolio. The U.S. Food and Drug Administration approved Ohtuvayre in June 2024 for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in adult patients. Ohtuvayre is the first novel inhaled mechanism for the treatment of COPD in more than 20 years and combines bronchodilator and non-steroidal anti-inflammatory effects. Ohtuvayre is also being evaluated in clinical trials for the treatment of non-cystic fibrosis bronchiectasis.

“This acquisition of Verona Pharma reflects the commitment we have to delivering innovative treatments to patients and our ability to execute on our science-led and value-driven business development strategy,” said Robert M. Davis, chairman and chief executive officer, Merck. “Ohtuvayre complements and expands our pipeline and portfolio of treatments for cardio-pulmonary diseases while delivering near- and long-term growth as well as value for shareholders. This novel, first-in-class treatment addresses an important unmet need for COPD patients persistently symptomatic based on its unique combination of bronchodilatory and non-steroidal anti-inflammatory effects. We look forward to welcoming the talented Verona Pharma team to Merck.”

“Today’s announced agreement with Merck is the culmination of years of focus and determination by the Verona Pharma team advancing Ohtuvayre, the first novel inhaled mechanism for the maintenance treatment of COPD in two decades,” said David Zaccardelli, president and chief executive officer, Verona Pharma. “Since launching Ohtuvayre in August 2024 we have seen rapid and accelerating uptake in the U.S. We believe Merck’s commercial footprint and industry-leading clinical capabilities will help accelerate the potential of Ohtuvayre to reach more patients living with COPD. This agreement will enable the strong launch trajectory of this important medicine and provides value to Verona Pharma shareholders.”

The transaction was unanimously approved by both the Merck and Verona Pharma Boards of Directors and is intended to be effected by way of a scheme of arrangement under UK law. Closing of the proposed acquisition is subject to approval under the Hart-Scott-Rodino Antitrust Improvements Act, approval of Verona Pharma shareholders, sanction by the High Court of Justice of England and Wales and other customary conditions. The transaction is expected to close in the fourth quarter of 2025 and will result in the capitalization of most of the purchase price as an intangible asset for Ohtuvayre (which will be amortized as a GAAP-only charge over the life of the product).

Investor Call

Merck will hold an investor call today, July 9, 2025 at 8 a.m. ET to discuss the proposed transaction. Journalists who wish to ask questions are requested to contact a member of Merck’s Media Relations team at the conclusion of the call. Investors, journalists and the general public may access a live audio webcast of the call via this weblink.

All participants may join the call by dialing (800) 369-3351 (U.S. and Canada Toll-Free) or (517) 308-9448 and using the access code 2398172.

Advisors

Citi and Morgan Stanley & Co. LLC acted as financial advisors to Merck in this transaction and Freshfields LLP acted as Merck’s legal advisor. Centerview Partners LLC acted as exclusive financial advisor to Verona Pharma and Latham & Watkins LLP as Verona Pharma’s legal advisor.

Ohtuvayre Indication and Important Safety Information

INDICATION

Ohtuvayre is indicated for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in adult patients.

IMPORTANT SAFETY INFORMATION

Contraindication: Ohtuvayre is contraindicated in patients with hypersensitivity to ensifentrine or any component of this product.

Warnings and Precautions:

Acute Episodes of Bronchospasm Ohtuvayre should not be used for the relief of acute symptoms, i.e., as rescue therapy for the treatment of acute episodes of bronchospasm. Acute symptoms should be treated with an inhaled, short-acting bronchodilator.

Paradoxical Bronchospasm As with other inhaled medicines, Ohtuvayre may produce paradoxical bronchospasm, which may be life threatening. If paradoxical bronchospasm occurs following dosing with Ohtuvayre, it should be treated immediately with an inhaled, short-acting bronchodilator. Ohtuvayre should be discontinued immediately and alternative therapy should be instituted.

Psychiatric Events Including Suicidality Before initiating treatment with Ohtuvayre, healthcare providers should carefully weigh the risk and benefits of treatment with Ohtuvayre in patients with a history of depression and/or suicidal thoughts or behavior. Patients, their caregivers, and families should be advised of the need to be alert for the emergence or worsening of insomnia, anxiety, depression, suicidal thoughts, or other mood changes, and if such changes occur to contact their healthcare provider. Healthcare providers should carefully evaluate the risks and benefits of continuing treatment with Ohtuvayre if such events occur.

Treatment with Ohtuvayre is associated with an increase in psychiatric adverse reactions. Psychiatric events including suicide-related adverse reactions were reported in clinical studies in patients who received Ohtuvayre (1 suicide attempt and 1 suicide). Additionally, the most commonly reported psychiatric adverse reactions in the pooled 24-week safety population were insomnia (6 patients [0.6%] Ohtuvayre 3 mg; 2 patients [0.3%] placebo), and anxiety (2 patients [0.2%] Ohtuvayre 3 mg; 1 patient [0.2%] placebo). Depression-related reactions including depression, major depression, and adjustment disorder with depressed mood occurred in 4 patients [0.4%] receiving Ohtuvayre and no patients receiving placebo.

Adverse Reactions: The most common adverse reactions ≥1% in Ohtuvayre and greater than placebo in the pooled population were back pain 1.8%, hypertension 1.7%, urinary tract infection 1.3%, and diarrhea 1.0%.

These are not all of the possible risks associated with Ohtuvayre.

Please see Prescribing Information for Ohtuvayre (ensifentrine) at: https://ohtuvayrehcp.com/wp-content/uploads/sites/2/2024/11/Ohtuvayre-US-Prescribing-Information.pdf, Patient Information for Ohtuvayre at: https://ohtuvayre.com/wp-content/uploads/2024/11/Ohtuvayre-US-Prescribing-Information.pdf.

About Chronic Obstructive Pulmonary Disease (COPD)

Chronic obstructive pulmonary disease (COPD) is a progressive respiratory condition that causes restricted airflow and breathing problems. Emphysema and chronic bronchitis are the two most common types of COPD. Common symptoms of COPD include shortness of breath an ongoing cough or a cough that produces a lot of mucus, wheezing, chest tightness or heaviness and fatigue. Smoking and air pollution are the most common causes of COPD. An estimated 390 million people suffer from COPD worldwide as of 2019 and COPD is the fourth leading cause of death worldwide. There is no cure for COPD.

About Ohtuvayre® (ensifentrine)

Ohtuvayre is the first inhaled therapy for the maintenance treatment of adults with COPD that combines bronchodilator and non-steroidal anti-inflammatory activities in one molecule. Verona has evaluated nebulized Ohtuvayre in its Phase 3 clinical program ENHANCE (“Ensifentrine as a Novel inHAled Nebulized COPD thErapy”) for COPD maintenance treatment. Ohtuvayre met the primary endpoint in both ENHANCE-1 and ENHANCE-2, demonstrating statistically significant and clinically meaningful improvements in lung function. A fixed-dose combination of ensifentrine and glycopyrrolate, a LAMA, is currently under development for the maintenance treatment of COPD.

About Verona Pharma

Verona Pharma is a biopharmaceutical company focused on developing and commercializing innovative therapies for the treatment of chronic respiratory diseases with significant unmet medical needs. Ohtuvayre® (ensifentrine) is the company’s first commercial product and the first inhaled therapy for the maintenance treatment of COPD that combines bronchodilator and non-steroidal anti-inflammatory activities in one molecule. Ensifentrine has potential in other respiratory diseases such as non-cystic fibrosis bronchiectasis. For more information, please visit www.veronapharma.com.

About Merck

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

UK Takeover Code does not apply

Verona Pharma is not a company subject to regulation under the City Code on Takeovers and Mergers (the “UK Takeover Code”), therefore no dealing disclosures are required to be made under Rule 8 of the UK Takeover Code by shareholders of Verona Pharma or Merck.

Additional Information and Where to Find it

In connection with the proposed transaction between Verona Pharma and Merck, Verona Pharma will file with the Securities and Exchange Commission (“SEC”) a proxy statement on Schedule 14A. Additionally, Verona Pharma may file other relevant materials with the SEC in connection with the proposed transaction. Investors and securityholders of Verona Pharma are urged to read the proxy statement (which will include an explanatory statement in respect of the Scheme of Arrangement of Verona Pharma, in accordance with the requirements of the U.K. Companies Act 2006) and any other relevant materials filed or that will be filed with the SEC, as well as any amendments or supplements to these materials and documents incorporated by reference therein, carefully and in their entirety when they become available because they contain or will contain important information about the proposed transaction and related matters. The definitive version of the proxy statement will be mailed or otherwise made available to Verona Pharma’s securityholders. Investors and securityholders will be able to obtain a copy of the proxy statement (when it is available) as well as other filings containing information about the proposed transaction that are filed by Verona Pharma or Merck with the SEC, free of charge on EDGAR at www.sec.gov, on the investor relations page of Verona Pharma’s website at https://www.veronapharma.com/investors/, by contacting Verona Pharma’s investor relations department at IR@veronapharma.com, or on Merck’s website at www.merck.com.

Participants in the Solicitation

Verona Pharma, Merck and certain of their directors and executive officers may be deemed to be participants in the solicitation of proxies from the shareholders of Verona Pharma in connection with the proposed transaction. Information about Verona Pharma’s directors and executive officers, including a description of their direct interests, by security holdings or otherwise, will be included in the proxy statement (when available). You may also find additional information about Verona Pharma’s directors and executive officers in Verona Pharma’s proxy statement for its 2025 Annual General Meeting filed on March 18, 2025 and Verona Pharma’s other filings with the SEC available at the SEC’s Internet site (www.sec.gov), including any statements of beneficial ownership on Form 3 or Form 4 filed with the SEC after such proxy statement. Information about Merck and its directors and executive officers can be found in Merck’s proxy statement filed on April 9, 2025 and Merck’s other filings with the SEC available at the SEC’s Internet site (www.sec.gov), including any statements of beneficial ownership on Form 3 or Form 4 filed with the SEC after such proxy statement. Verona Pharma shareholders may obtain additional information regarding the direct and indirect interests of the participants in the solicitation of proxies in connection with the proposed transaction, including the interests of Verona Pharma directors and executive officers in the proposed transaction, which may be different than those of Verona Pharma shareholders generally, by reading the proxy statement and any other relevant documents that are filed or will be filed with the SEC relating to the proposed transaction. You may obtain free copies of these document using the sources indicated above.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA

This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995, including with respect to the company’s proposed acquisition of Verona Pharma, and readers are cautioned not to place undue reliance on such statements. Such forward-looking statements include, but are not limited to, the ability of the company and Verona Pharma to complete the transactions contemplated by the transaction agreement, including the parties’ ability to satisfy the conditions to the consummation of the transaction contemplated thereby, statements about the expected timetable for completing the transaction, the company’s and Verona Pharma’s beliefs and expectations and statements about the benefits sought to be achieved in the company’s proposed acquisition of Verona Pharma, the potential effects of the acquisition on both the company and Verona Pharma, the possibility of any termination of the transaction agreement, as well as the expected benefits and success of Verona Pharma’s products and product candidates. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees that the conditions to the closing of the proposed transaction will be satisfied on the expected timetable or at all, or that any pipeline candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include, but are not limited to, uncertainties as to the timing of the proposed transaction; the risk that competing offers or acquisition proposals will be made; the possibility that various conditions to the consummation of the proposed transaction contained in the transaction agreement may not be satisfied or waived (including, but not limited to, the failure to obtain the approval of the proposed transaction by Verona Pharma shareholders and the failure to obtain the sanction of the High Court of Justice of England and Wales); the effects of disruption from the transactions contemplated by the transaction agreement and the impact of the announcement and pendency of the transactions on Verona Pharma’s business; the risk that shareholder litigation in connection with the transaction may result in significant costs of defense, indemnification and liability; general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise, except to the extent required by law. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

Forward-Looking Statements of Verona Pharma

This news release includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995, including with respect to the proposed acquisition of Verona Pharma, and readers are cautioned not to place undue reliance on such statements. Such forward-looking statements include, but are not limited to, the ability of Merck and Verona Pharma to complete the transactions contemplated by the transaction agreement, including statements about the transaction contemplated thereby, statements about the expected timetable for completing the transaction, Verona Pharma’s beliefs and expectations and statements about the benefits sought to be achieved in the proposed acquisition, the potential effects of the acquisition on Verona Pharma, as well as the expected benefits and success of Verona Pharma’s products and product candidates. These statements are based upon the current beliefs and expectations of Verona Pharma’s management and are subject to significant risks and uncertainties. There can be no guarantees that the conditions to the closing of the proposed transaction will be satisfied on the expected timetable or at all, or that any pipeline candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include, but are not limited to, uncertainties as to the timing of the proposed transaction; the risk that competing offers or acquisition proposals will be made; the possibility that various conditions to the consummation of the proposed transaction contained in the transaction agreement may not be satisfied or waived (including, but not limited to, the failure to obtain the approval of the proposed transaction by Verona Pharma shareholders and the failure to obtain the sanction of the High Court of Justice of England and Wales); the effects of disruption from the transactions contemplated by the transaction agreement and the impact of the announcement and pendency of the transactions on Verona Pharma’s business; the risk that shareholder litigation in connection with the transaction may result in significant costs of defense, indemnification and liability; Verona Pharma’s dependence on the successful commercialization of Ohtuvayre and the uncertain market acceptance of Ohtuvayre as a treatment for COPD; and risks related to pharmaceutical product development, including Verona Pharma’s ongoing development of ensifentrine and any other product candidates and combinations, and the uncertainty of clinical success.

Verona Pharma undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise, except to the extent required by law. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in Verona Pharma’s Annual Report on Form 10-K for the year ended December 31, 2024 and Verona Pharma’s other filings with the SEC.

Merck Investor Contact:
Peter Dannenbaum
(732) 594-1579

Merck Media Contacts:
Robert Josephson
(203) 914- 2372

Justine Moore
(347) 281-3754

Verona Pharma plc:
Victoria Stewart
+1 (844) 341-9901
IR@veronapharma.com

Argot Partners:
Verona Pharma – US Investor Enquiries
+1 (212) 600-1902
verona@argotpartners.com

Ten Bridge Communications:
Verona Pharma – International / US Media Enquiries
Wendy Ryan
+1 (781) 316-4424
tbcverona@tenbridgecommunications.com

Source: Merck & Co., Inc.

Merck (NYSE: MRK), known as MSD outside of the United States and Canada, announced today that new data from its research pipeline for HIV prevention and treatment will be presented at the 13th International AIDS Society Conference on HIV Science (IAS 2025) taking place July 13-17, 2025, in Kigali, Rwanda.

Merck will share new scientific findings from its HIV clinical development programs, including Phase 2 data on the safety and pharmacokinetics of MK-8527, an investigational, novel nucleoside reverse transcriptase translocation inhibitor (NRTTI), dosed orally once monthly, in development for the prevention of HIV as pre-exposure prophylaxis (PrEP).

HIV clinical data presented at IAS 2025 from three Phase 3 trials (P051: NCT05631093; P052: NCT05630755; P054: NCT05766501) will examine the impact of preexisting resistance-associated mutations (RAMs) in proviral DNA on the virologic response to doravirine/islatravir (DOR/ISL), with a primary focus on M184I/V in proviral DNA.

Data will also be presented on the clinical development program for a once-weekly oral combination of islatravir and ulonivirine (ISL/ULO) for the treatment of adults with HIV-1 infection. Data from two Phase 1 trials evaluating the safety and tolerability of weekly ulonivirine and drug interactions between islatravir and ulonivirine dosed weekly in adults without HIV and a Phase 2b dose-ranging study utilizing a higher (20mg) dose of islatravir and 3 doses of ulonivirine in treatment naive adults living with HIV-1 will be presented. Based on results from these trials and pharmacokinetic modeling that will also be presented, a once-weekly oral combination of islatravir (2mg) and ulonivirine (200mg) (MK-8591B) is moving forward in clinical development.

“As we continue to advance our HIV research, we are excited to present data from across our HIV pipeline at IAS 2025, including new data from our nucleoside reverse transcriptase translocation inhibitors development programs,” said Dr. Elizabeth Rhee, vice president, global clinical development, Merck Research Laboratories. “With daily, weekly and monthly oral regimens in development, we aim to offer choices that can help address the evolving needs of individuals living with or impacted by HIV.”

Select abstracts in the IAS 2025 program include:

Abstract Title and Author

Date

HIV PREVENTION

Safety and Pharmacokinetics of Once-Monthly MK-8527: a Phase 2 Study in Adults at Low Risk of HIV-1 Exposure, Mayer, K, et al.

Late-Breaker

Oral Presentation

Wednesday, July 16, 2025

(15:00 – 16:00 CAT)

HIV TREATMENT

Switching to Doravirine/Islatravir (100mg/0.25mg) Once Daily Maintained Viral Suppression in the Presence of Archived M184I/V Resistance-Associated Mutations in Proviral DNA, Diamond, T, et al.

Poster Session

Wednesday, July 16, 2025

(12:15 – 13:15 CAT)

 

A Double-Blind, Active-Controlled, Phase 2b Study to Evaluate the Efficacy and Safety of Ulonivirine in Combination with Islatravir in Virologically Suppressed Adults Living With HIV-1, Molina, J.M., et al. (*)

Oral Presentation

ART Strategies

Tuesday, July 15, 2025 (10:45 – 11:45 CAT)

A Double-Blind Placebo-Controlled, Phase 1 Study to Evaluate Extended Multiple Dosing of Ulonivirine (MK-8507) in Adults Without HIV, Nussbaum, J, et al.

Virtual Poster

 

An Open-Label Phase 1 Study to Evaluate Drug Interactions Between Multiple Weekly Doses of Ulonivirine (MK-8507) and Single Doses of Islatravir in Adults Without HIV, Nussbaum, J, et al.

Virtual Poster

 

Phase 2 Once-Weekly Dose Optimization for Ulonivirine (MK-8507) in Combination with Islatravir (2mg), Pham, M, et al.

Virtual Poster

(*) Previous ulonivirine development program utilizing a higher (20mg) dose of islatravir.

This year at IAS, Merck will host a policy symposium “Harnessing the Private Sector to Deliver HIV Prevention” on Tuesday, July 15, from 18:00 – 19:30 CAT. Merck will also host a medical symposium “Let’s Talk About It – Practical Case Discussions” on Wednesday, July 16, from 12:15 – 13:15 CAT, which will cover critical considerations when treating HIV today, as well as a deep dive into the DOR/ISL resistance profile based on Phase 3 data. Both events will be open to all registered attendees, virtually and in-person.

Separately, Merck will be hosting a virtual investor event where scientific and commercial leaders will give an overview of the company’s advancing research pipeline in HIV treatment and prevention on Thursday, July 17, at 9:00AM ET. Investors, analysts, members of the media, and the general public are invited to listen to a webcast of the presentation at this weblink.

For more details about Merck’s clinical development program in HIV treatment and prevention, click here.

Merck’s Commitment to HIV
For more than 35 years, Merck has been committed to scientific research and discovery in HIV leading to scientific breakthroughs that have helped change HIV treatment. Our work has helped pioneer the development of new options across multiple drug classes to help those impacted by HIV. Today, we are developing a series of antiviral options designed to help people manage their HIV and to help prevent HIV, with the goal of reducing the growing burden of infection worldwide. We want to ensure people are not defined by HIV, and our work focuses on transformational innovations, collaborations with others in the global HIV community, and access initiatives aimed at helping to end the HIV epidemic for everyone.

Indications and usage for PIFELTRO® (doravirine) and DELSTRIGO® (doravirine, lamivudine, and tenofovir disoproxil fumarate) in the U.S.
PIFELTRO is indicated in combination with other antiretroviral (ARV) agents for the treatment of HIV-1 infection in adult patients with no prior ARV treatment history or to replace the current ARV regimen in those who are virologically suppressed (HIV-1 RNA less than 50 copies per mL) on a stable ARV regimen with no history of treatment failure and no known substitutions associated with resistance to doravirine.

DELSTRIGO is indicated as a complete regimen for the treatment of HIV-1 infection in adult patients with no prior ARV treatment history or to replace the current ARV regimen in those who are virologically suppressed (HIV-1 RNA less than 50 copies per mL) on a stable ARV regimen with no history of treatment failure and no known substitutions associated with resistance to the individual components of DELSTRIGO.

Selected Safety Information

Warning: Posttreatment Acute Exacerbation of Hepatitis B Virus (HBV) for DELSTRIGO
All patients with HIV-1 should be tested for the presence of HBV before initiating ARV therapy. Severe acute exacerbations of HBV have been reported in people with concomitant HIV-1 and HBV who have discontinued products containing lamivudine or tenofovir disoproxil fumarate (TDF), which are components of DELSTRIGO. Patients coinfected with HIV-1 and HBV who discontinue DELSTRIGO should be monitored with both clinical and laboratory follow-up for at least several months after stopping DELSTRIGO. If appropriate, initiation of anti-HBV therapy may be warranted.

Contraindications
PIFELTRO and DELSTRIGO are contraindicated when coadministered with drugs that are strong cytochrome P450 (CYP)3A enzyme inducers (including the anticonvulsants carbamazepine, oxcarbazepine, phenobarbital, and phenytoin; the androgen receptor inhibitor enzalutamide; the antimycobacterials rifampin and rifapentine; the cytotoxic agent mitotane; and the herbal product St. John’s wort (Hypericum perforatum)), as significant decreases in doravirine plasma concentrations may occur, which may decrease the effectiveness of DELSTRIGO and PIFELTRO.

DELSTRIGO is contraindicated in patients with a previous hypersensitivity reaction to lamivudine.

Warnings and Precautions
Severe Skin Reactions
Severe skin reactions, including Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN), have been reported during the postmarketing experience with doravirine-containing regimens. Discontinue PIFELTRO or DELSTRIGO, and other medications known to be associated with severe skin reactions, immediately if a painful rash with mucosal involvement or a progressive severe rash develops. Clinical status should be closely monitored, and appropriate therapy should be initiated.

New or Worsening Renal Impairment
Renal impairment, including cases of acute renal failure and Fanconi syndrome, have been reported with the use of TDF. DELSTRIGO should be avoided with concurrent or recent use of a nephrotoxic agent (eg, high-dose or multiple NSAIDs). Cases of acute renal failure after initiation of high-dose or multiple NSAIDs have been reported in people living with HIV with risk factors for renal dysfunction who appeared stable on TDF.

Prior to or when initiating DELSTRIGO, and during treatment, assess serum creatinine, estimated creatinine clearance, urine glucose, and urine protein in all patients. In patients with chronic kidney disease, also assess serum phosphorus. Discontinue DELSTRIGO in patients who develop clinically significant decreases in renal function or evidence of Fanconi syndrome. Discontinue DELSTRIGO if estimated creatinine clearance declines below 50 mL/min.

Bone Loss and Mineralization Defects
In clinical trials in adults living with HIV, TDF was associated with slightly greater decreases in bone mineral density (BMD) and increases in biochemical markers of bone metabolism. Serum parathyroid hormone levels and 1,25 Vitamin D levels were also higher. Cases of osteomalacia associated with proximal renal tubulopathy have been reported with the use of TDF. The effects of TDF-associated changes in BMD and biochemical markers on long-term bone health and future fracture risk in adults are unknown.

Immune Reconstitution Syndrome
Immune reconstitution syndrome can occur, including the occurrence of autoimmune disorders with variable time to onset, which may necessitate further evaluation and treatment.

Drug Interactions
Because DELSTRIGO is a complete regimen, coadministration with other antiretroviral medications for the treatment of HIV-1 infection is not recommended.

Coadministration of PIFELTRO with efavirenz, etravirine, or nevirapine is not recommended.

If DELSTRIGO is coadministered with rifabutin, take one tablet of DELSTRIGO once daily, followed by one tablet of doravirine (PIFELTRO) approximately 12 hours after the dose of DELSTRIGO.

If PIFELTRO is coadministered with rifabutin, increase PIFELTRO dosage to one tablet twice daily (approximately 12 hours apart).

Consult the full Prescribing Information prior to and during treatment for more information on potential drug-drug interactions.

Dosage and Administration/Specific Populations
Renal Impairment
Because DELSTRIGO is a fixed-dose combination tablet and the dosage of lamivudine and TDF cannot be adjusted, DELSTRIGO is not recommended in patients with estimated creatinine clearance less than 50 mL/min.

Adverse Reactions
The most common adverse reactions with DELSTRIGO (incidence ≥5%, all intensities) were dizziness (7%), nausea (5%), and abnormal dreams (5%). The most common adverse reactions with PIFELTRO (incidence ≥5%, all intensities) were nausea (7%), dizziness (7%), headache (6%), fatigue (6%), diarrhea (6%), abdominal pain (5%), and abnormal dreams (5%).

By week 96 in DRIVE-FORWARD, 2% of adult participants in the PIFELTRO group and 3% in the darunavir+ritonavir (DRV+r) group had adverse events leading to discontinuation of study medication.

By week 96 in DRIVE-AHEAD, 3% of adult participants in the DELSTRIGO group and 7% in the efavirenz (EFV)/emtricitabine (FTC)/TDF group had adverse events leading to discontinuation of study medication.

In DRIVE-FORWARD, mean changes from baseline at week 48 in LDL-cholesterol (LDL-C) and non-HDL-cholesterol (non-HDL-C) were pre-specified. LDL-C: -4.6 mg/dL in the PIFELTRO group vs 9.5 mg/dL in the DRV+r group. Non-HDL-C: -5.4 mg/dL in the PIFELTRO group vs 13.7 mg/dL in the DRV+r group. The clinical benefits of these findings have not been demonstrated.

In DRIVE-AHEAD, mean changes from baseline at week 48 in LDL-C and non-HDL-C were pre-specified. LDL-C: -2.1 mg/dL in the DELSTRIGO group vs 8.3 mg/dL in the EFV/FTC/TDF group. Non-HDL-C: -4.1 mg/dL in the DELSTRIGO group vs 12.7 mg/dL in the EFV/FTC/TDF group. The clinical benefits of these findings have not been demonstrated.

In DRIVE-SHIFT, mean changes from baseline at week 24 in LDL-C and non-HDL-C were pre-specified. LDL-C: -16.3 mg/dL in the DELSTRIGO group vs -2.6 mg/dL in the PI + ritonavir group. Non-HDL-C: -24.8 mg/dL in the DELSTRIGO group vs -2.1 mg/dL in the PI + ritonavir group. The clinical benefits of these findings have not been demonstrated.

In DRIVE-AHEAD, neuropsychiatric adverse events were reported in the three pre-specified categories of sleep disorders and disturbances, dizziness, and altered sensorium. Twelve percent of adult participants in the DELSTRIGO group and 26% in the EFV/FTC/TDF group reported neuropsychiatric adverse events of sleep disorders and disturbances; 9% in the DELSTRIGO group and 37% in the EFV/FTC/TDF group reported dizziness; and 4% in the DELSTRIGO group and 8% in the EFV/FTC/TDF group reported altered sensorium.

The safety of DELSTRIGO in virologically-suppressed adults was based on week 48 data from participants in the DRIVE-SHIFT trial. Overall, the safety profile in virologically-suppressed adult participants was similar to that in participants with no ARV treatment history.

Serum ALT and AST Elevations: In the DRIVE-SHIFT trial, 22% and 16% of participants in the immediate switch group experienced ALT and AST elevations greater than 1.25 X ULN, respectively, through 48 weeks on DELSTRIGO. For these ALT and AST elevations, no apparent patterns with regard to time to onset relative to switch were observed. One percent of participants had ALT or AST elevations greater than 5 X ULN through 48 weeks on DELSTRIGO. The ALT and AST elevations were generally asymptomatic, and not associated with bilirubin elevations. In comparison, 4% and 4% of participants in the delayed switch group experienced ALT and AST elevations of greater than 1.25 X ULN through 24 weeks on their baseline regimen.

Pregnancy/Breastfeeding
There is a pregnancy exposure registry that monitors pregnancy outcomes in individuals exposed to PIFELTRO or DELSTRIGO during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263.

Inform individuals with HIV-1 infection of the potential risks of breastfeeding, including: (1) HIV-1 transmission (in HIV-1–negative infants), (2) developing viral resistance (in HIV-1–positive infants), and (3) serious adverse reactions in a breastfed infant similar to those seen in adults.

About Merck
At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA
This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

Please see Prescribing Information for PIFELTRO (doravirine) at: https://www.merck.com/product/usa/pi_circulars/p/pifeltro/pifeltro_pi.pdf and Patient Information for PIFELTRO at: https://www.merck.com/product/usa/pi_circulars/p/pifeltro/pifeltro_ppi.pdf

Please see Prescribing Information for DELSTRIGO (doravirine, lamivudine, and tenofovir disoproxil fumarate) at: https://www.merck.com/product/usa/pi_circulars/d/delstrigo/delstrigo_pi.pdf and Patient Information for DELSTRIGO at: https://www.merck.com/product/usa/pi_circulars/d/delstrigo/delstrigo_ppi.pdf

Media Contacts:
Julie Cunningham, (617) 519-6264
Deb Wambold, (215) 779-2234

Investor Contacts:
Peter Dannenbaum, (732) 594-1579
Steven Graziano, (732) 594-1583

Source: Merck & Co., Inc.

Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced that the U.S. Food and Drug Administration (FDA) has accepted and granted priority review for a new supplemental Biologics License Application (sBLA) seeking approval to update the U.S. product label based on the Phase 3 ZENITH trial for WINREVAIR™ (sotatercept-csrk). In 2024, WINREVAIR was approved for the treatment of adults with pulmonary arterial hypertension (PAH, Group 1 PH) to increase exercise capacity, improve WHO* functional class (FC), and reduce the risk of clinical worsening events. The FDA has set a Prescription Drug User Fee Act (PDUFA), or target action date, of Oct. 25, 2025.

The sBLA is based on data from the Phase 3 ZENITH trial. The ZENITH trial was the first PAH Phase 3 outcome study to use a primary endpoint comprised entirely of major morbidity and mortality events. It was also the first PAH Phase 3 study stopped early by an independent data monitoring committee for overwhelming efficacy. In ZENITH, WINREVAIR demonstrated a 76% reduction in the risk of a composite of all-cause death, lung transplantation, and hospitalization for PAH ≥24 hours compared to placebo. Improvement was observed early in treatment with increasing benefit throughout the study. The safety profile of WINREVAIR in ZENITH was generally consistent with that observed in previous studies. These results were published in the New England Journal of Medicine.

“We are pleased that the FDA has accepted our sBLA for WINREVAIR and granted a priority review to consider an update to labeling for WINREVAIR to include the impressive results of ZENITH. There remains a significant unmet medical need for patients living with PAH who, despite being on background therapy, remain at higher risk of morbidity and mortality,” said Dr. Joerg Koglin, senior vice president, global clinical development, Merck Research Laboratories. “The FDA’s Priority Review designation acceptance of our sBLA reinforces our confidence in WINREVAIR for a broad range of patients and represents a critical step toward advancing the treatment of PAH.”

WINREVAIR is currently approved in more than 45 countries based on the results from the STELLAR trial.

*World Health Organization

About ZENITH
The ZENITH study (NCT04896008) is a global, double-blind, placebo-controlled clinical trial to evaluate WINREVAIR when added to maximum tolerated background PAH therapy on time to first event of all-cause death, lung transplantation, or PAH worsening related hospitalization of ≥ 24 hours, in adult participants with WHO functional class III or IV PAH at high risk of mortality. ZENITH study inclusion criteria required Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL) Lite 2.0 risk score of ≥9.

The study enrolled 172 participants, who were randomized in a 1:1 ratio to either WINREVAIR plus background PAH therapy or placebo plus background PAH therapy. The primary composite outcome measure was time to first confirmed major morbidity or mortality event. Events were defined as all-cause death, lung transplantation, or PAH worsening-related hospitalization of ≥ 24 hours. Secondary outcome measures included overall survival, transplant-free survival and several additional measures. The study excluded patients with PAH Group 1 subtypes: human immunodeficiency virus (HIV)-associated PAH and PAH associated with portal hypertension as well as diagnosis of pulmonary veno-occlusive diseases, pulmonary capillary hemangiomatosis or overt signs of capillary and/or venous involvement.

Participants who completed the ZENITH trial were offered the opportunity to receive WINREVAIR as part of the open-label, long-term extension study, SOTERIA (NCT04796337), consistent with that study’s eligibility criteria.

About WINREVAIR (sotatercept-csrk) for injection, for subcutaneous use, 45 mg, 60 mg
WINREVAIR is FDA-approved for the treatment of adults with pulmonary arterial hypertension (PAH, WHO Group 1) to increase exercise capacity, improve WHO functional class (FC) and reduce the risk of clinical worsening events. WINREVAIR is the first activin signaling inhibitor therapy approved to treat PAH. WINREVAIR improves the balance between pro-proliferative and anti-proliferative signaling to modulate vascular proliferation. In preclinical models, WINREVAIR induced cellular changes that were associated with thinner vessel walls, partial reversal of right ventricular remodeling, and improved hemodynamics.

WINREVAIR is the subject of a licensing agreement with Bristol Myers Squibb.

Selected Safety Information for WINREVAIR in the U.S.
WINREVAIR may increase hemoglobin (Hgb). Severe erythrocytosis may increase the risk of thromboembolic events or hyperviscosity syndrome. Monitor Hgb before each dose for the first 5 doses, or longer if values are unstable, and periodically thereafter, to determine if dose adjustments are required.

WINREVAIR may decrease platelet count. Severe thrombocytopenia may increase the risk of bleeding. Thrombocytopenia occurred more frequently in patients also receiving prostacyclin infusion. Do not initiate treatment if platelet count is <50,000/mm3. Monitor platelets before each dose for the first 5 doses, or longer if values are unstable, and periodically thereafter to determine whether dose adjustments are required.

In clinical studies, serious bleeding (eg, gastrointestinal, intracranial hemorrhage) was reported in 4% of patients taking WINREVAIR and 1% of patients taking placebo. Patients with serious bleeding were more likely to be on prostacyclin background therapy and/or antithrombotic agents, or have low platelet counts. Advise patients about signs and symptoms of blood loss. Do not administer WINREVAIR if the patient is experiencing serious bleeding.

WINREVAIR may cause fetal harm when administered to a pregnant woman. Advise pregnant women of the potential risk to a fetus. Advise females of reproductive potential to use an effective method of contraception during treatment with WINREVAIR and for at least 4 months after the final dose. Pregnancy testing is recommended for females of reproductive potential before starting WINREVAIR treatment.

Based on findings in animals, WINREVAIR may impair female and male fertility. Advise patients on the potential effects on fertility.

The most common adverse reactions occurring in the phase 3 clinical trial (≥10% for WINREVAIR and at least 5% more than placebo) were headache (24.5% vs 17.5%), epistaxis (22.1% vs 1.9%), rash (20.2% vs 8.1%), telangiectasia (16.6% vs 4.4%), diarrhea (15.3% vs 10.0%), dizziness (14.7% vs 6.2%), and erythema (13.5% vs 3.1%).

Because of the potential for serious adverse reactions in the breastfed child, advise patients that breastfeeding is not recommended during treatment with WINREVAIR, and for 4 months after the final dose.

About PAH
Pulmonary arterial hypertension (PAH) is a rare, progressive and life-threatening blood vessel disorder characterized by the constriction of small pulmonary arteries and elevated blood pressure in the pulmonary circulation. Approximately 40,000 people in the U.S. are living with PAH. The disease progresses rapidly for many patients. PAH results in significant strain on the heart, leading to limited physical activity, heart failure and reduced life expectancy. The five-year mortality rate for patients with PAH is approximately 43%.

About Merck
At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA
This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

Please see Prescribing Information for WINREVAIR (sotatercept-csrk) at http://www.merck.com/product/usa/pi_circulars/w/winrevair/winrevair_pi.pdf, Patient Information for WINREVAIR at http://www.merck.com/product/usa/pi_circulars/w/winrevair/winrevair_ppi.pdf, and Instructions for Use for WINREVAIR (1-vial kit, 2-vial kit) at https://www.merck.com/product/usa/pi_circulars/w/winrevair/winrevair_ifu_1-vial_2-vial_kits.pdf.

Media Contacts:

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Investor Contacts:

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Steven Graziano
(732) 594-1583

Source: Merck & Co., Inc.