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June 4, 2017 8:00 am ET

Findings to Be Presented at 2017 ASCO Annual Meeting Also Include Updated Data Evaluating Duration of Response in Previously Untreated (First-Line) Urothelial Carcinoma Patients Ineligible for Cisplatin-Based Therapy

Merck (NYSE:MRK), known as MSD outside the United States and Canada,
today announced updated results from KEYNOTE-045 and KEYNOTE-052, two
studies investigating KEYTRUDA^® (pembrolizumab), the
company’s anti-PD-1 therapy, in certain patients with locally advanced
or metastatic urothelial carcinoma, a type of bladder cancer. These data
– which include updated survival and biomarker analyses – demonstrate
the clinical benefit of KEYTRUDA as a second-line therapy for patients
post-platinum failure and as a first-line treatment for patients
ineligible for cisplatin-based therapy. Specifically, in the second-line
setting, KEYTRUDA improved overall survival (OS) compared to
chemotherapy – reducing the risk of death by 30 percent (HR, 0.70 [95%
CI, 0.57-0.86], p = 0.0004) – and, in the first-line setting, KEYTRUDA
demonstrated an overall response rate (ORR) of 29 percent (95% CI,
25-34). Findings will be presented in two oral sessions at the 2017
American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago
on Monday, June 5, from 8:12 to 8:36 a.m. CDT (Location: Arie Crown
Theater) (Abstracts #4501 and #4502).

“Historically, there have been limited treatment options for patients
with advanced urothelial bladder cancer,” said Dean F. Bajorin, M.D.,
medical oncologist at Memorial Sloan Kettering Cancer Center. “For
patients with this devastating disease, the efficacy and safety profile
we have observed with KEYTRUDA in these treatment settings represent an
important new option.”

“The updated data at ASCO in previously treated urothelial cancer
patients continue to support the overall survival benefit we have
observed in the second-line treatment setting and the response rates
demonstrated in cisplatin-ineligible patients,” said Dr. Roger Dansey,
senior vice president and therapeutic area head, oncology late-stage
development, Merck Research Laboratories. “Beyond these two studies, we
are studying KEYTRUDA in other treatment settings and look forward to
executing on our robust clinical development program in bladder cancer.”

The KEYTRUDA (pembrolizumab) clinical development program includes more
than 30 tumor types in more than 500 clinical trials, including more
than 300 trials that combine KEYTRUDA with other cancer treatments.
Currently, Merck has the largest immuno-oncology clinical development
program in bladder cancer, with 29 trials underway involving KEYTRUDA as
monotherapy and in combination, including four registration-enabling
studies.

Data in Second-Line Post-Platinum Failure Patients, KEYNOTE-045
(Abstract #4501)

KEYNOTE-045 is a multicenter, randomized, active-controlled, phase 3
trial, investigating KEYTRUDA in 542 patients with locally advanced or
metastatic urothelial carcinoma with disease progression on or after
platinum-containing chemotherapy (additional details on the trial design
are provided below). Data to be presented at ASCO are based on longer
follow-up (median follow-up of 18.5 months as of Jan. 18, 2017; range:
14.2-26.5), which continues to show a superior OS advantage with
KEYTRUDA compared to chemotherapy in the second-line treatment of
patients with advanced urothelial carcinoma who have progressed during
or following platinum-containing chemotherapy, regardless of PD-L1
expression.

Analyses of the primary endpoints showed a 30 percent reduction in the
risk of death with KEYTRUDA (n=270) compared to chemotherapy (n=272)
(HR, 0.70 [95% CI, 0.57-0.86], p = 0.0004). The median OS with KEYTRUDA
was 10.3 months (95% CI, 8.0-12.3) versus 7.4 months with chemotherapy
(95% CI, 6.1-8.1). As previously reported, there was no significant
improvement in progression-free survival (PFS) between arms (HR, 0.96
[95% CI, 0.79-1.16], p= 0.32). The median PFS was 2.1 months (95% CI,
2.0-2.2) in the KEYTRUDA arm and 3.3 months (95% CI, 2.4-3.5) in the
chemotherapy arm. The six-month, 12-month and 18-month PFS rates in the
KEYTRUDA arm were 28.8 percent, 17.6 percent and 16.8 percent,
respectively; the six-month, 12-month and 18-month PFS rates in the
chemotherapy arm were 28.4 percent, 7.9 percent and 3.5 percent,
respectively.

Analyses of the secondary endpoints showed a higher ORR with KEYTRUDA
compared to chemotherapy. In patients treated with KEYTRUDA, the ORR was
21.1 percent – with a complete response rate of 7.8 percent and a
partial response rate of 13.3 percent. In patients treated with
chemotherapy, the ORR was 11.0 percent – with a complete response rate
of 2.9 percent and a partial response rate of 8.1 percent. The median
duration of response had not been reached in the KEYTRUDA
(pembrolizumab) arm (range: 1.6+-20.7+) and was 4.4 months in the
chemotherapy arm (range: 1.4+-20.3+).

The safety profile of KEYTRUDA was consistent with that observed in
previously reported studies. Grade 1-2 treatment-related adverse events
in the KEYTRUDA arm included anemia, asthenia, constipation, decreased
appetite, diarrhea, fatigue, nausea, peripheral neuropathy, peripheral
sensory neuropathy and pruritus. Grade 3-5 treatment-related adverse
events in the KEYTRUDA arm included anemia, asthenia, decreased
neutrophils, diarrhea, fatigue, nausea and pruritus. Grade 3-5
immune-mediated adverse events included adrenal insufficiency, colitis,
nephritis, pneumonitis and severe skin reaction.

Data in First-Line Cisplatin-Ineligible Patients, KEYNOTE-052
(Abstract #4502)

KEYNOTE-052 is a multicenter, open-label, single-arm phase 2 trial,
investigating KEYTRUDA in 370 patients with locally advanced or
metastatic urothelial carcinoma who were not eligible for
cisplatin-containing chemotherapy (additional details on the trial
design are provided below). Findings to be presented at ASCO, which
include the full study population and longer follow-up, show that in the
first-line treatment setting many patients with cisplatin-ineligible
advanced urothelial carcinoma treated with KEYTRUDA continue to
experience complete or partial responses.

In the full study population (n=370), the efficacy analysis showed an
ORR of 29 percent (95% CI, 25-34) – with a complete response rate of
seven percent (95% CI, 5-10) and a partial response rate of 22 percent
(95% CI, 18-27). At the time of analysis, 67 percent of responses were
ongoing – of which 82 percent had lasted six months or longer. The
median duration of response had not been reached at the time of analysis
(95% CI, 12 months-not reached).

The study included a training set (the first 100 patients enrolled),
which was used to identify the CPS cut-point for PD-L1 expression, and a
validation set (which includes all subsequent 270 evaluable
patients) intended to validate the combined positive score (CPS)
cut-point. Of the 270 patients in the validation set, in patients with
PD-L1 expression of less than 10 percent (CPS <10%), the ORR was 23
percent (95% CI, 17-29), with a complete response rate of three percent
(95% CI, 1-6) and a partial response rate of 20 percent (95% CI, 15-27);
in patients expressing PD-L1 equal to or greater than 10 percent (CPS
≥10%), the ORR was 51 percent (95% CI, 40-63), with a complete response
rate of 18 percent (95% CI, 10-28) and a partial response rate of 34
percent (95% CI, 24-45).

The safety profile of KEYTRUDA was consistent with that observed in
previously reported studies. The treatment-related adverse events (any
grade occurring in 5% or more of patients [n=370] in descending order)
were fatigue (18%), pruritus (17%), rash (12%), decreased appetite
(10%), hypothyroidism (10%), diarrhea (9%), and nausea (8%). Grade 3-5
treatment-related adverse events observed (occurring in 3 or more of
patients) were fatigue (2%), colitis (2%), muscle weakness (1%),
alkaline phosphatase increase (1%), diarrhea (1%), pneumonitis (1%), AST
increase (1%), asthenia (1%), hepatitis (1%), and ALT increase (1%).
Grade 3-5 immune-mediated adverse events included: adrenal
insufficiency, colitis, dermatitis bullous, diabetic ketoacidosis,
hepatitis, myocarditis, pneumonitis, thyroiditis, type 1 diabetes
mellitus, tubulointerstitial nephritis and rash.

About the KEYNOTE-045 and KEYNOTE-052 Studies

KEYNOTE-045 is a multicenter, randomized, active-controlled, phase 3
trial, investigating KEYTRUDA (pembrolizumab) in 542 patients with
locally advanced or metastatic urothelial carcinoma with disease
progression on or after platinum-containing chemotherapy. Patients were
randomized to receive either KEYTRUDA 200 mg every three weeks (n=270)
or investigator’s choice of any of the following chemotherapy regimens,
all given intravenously, every three weeks (n=272): paclitaxel 175 mg/m²
(n=84), docetaxel 75 mg/m² (n=84), or vinflunine 320 mg/m²
(n=87). Treatment continued until unacceptable toxicity or disease
progression; patients without disease progression could be treated for
up to 24 months. The primary endpoints were OS and PFS, as assessed by
blinded independent central review (BICR) per RECIST (Response
Evaluation Criteria in Solid Tumors) v1.1; additional efficacy outcome
measures included ORR, as assessed by BICR per RECIST 1.1, and duration
of response. Efficacy was assessed in all patients, as well as in
patients with PD-L1 expression – as determined by a CPS of equal to or
greater than 10 percent (CPS ≥10%) (KEYTRUDA arm: n=74/270; chemotherapy
arm; n=90/272).

KEYNOTE-052 is a multicenter, open-label, single-arm phase 2 trial,
investigating KEYTRUDA in 370 patients with locally advanced or
metastatic urothelial carcinoma who were not eligible for
cisplatin-containing chemotherapy. Patients received KEYTRUDA at a dose
of 200 mg every three weeks until unacceptable toxicity or disease
progression; patients without disease progression could be treated for
up to 24 months. The study included a training set (the first 100
patients enrolled), which was used to identify the CPS cut-point for
PD-L1 expression, and a validation set, which includes all subsequent 270
evaluable patients and will be used to validate the CPS cut-point.
The primary endpoints include ORR in all patients enrolled in the study
(total study population) and in patients with PD-L1 positive tumors
(expression of one percent or more); secondary endpoints include
duration of response, PFS and OS. Tumor response was measured according
to RECIST v1.1 by central imaging vendor review.

About KEYTRUDA

^®

(pembrolizumab) Injection

KEYTRUDA is an anti-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.

Studies of KEYTRUDA – from the largest immuno-oncology program in the
industry with more than 500 trials – include a wide variety of cancers
and treatment settings. The KEYTRUDA clinical program seeks to
understand factors that predict a patient’s likelihood of benefitting
from treatment with KEYTRUDA, including the exploration of several
different biomarkers across a broad range of tumors.

KEYTRUDA is administered as an intravenous infusion over 30 minutes
every three weeks for the approved indications. KEYTRUDA for injection
is supplied in a 100 mg single-dose vial.

KEYTRUDA (pembrolizumab) Indications and Dosing

Melanoma

KEYTRUDA is indicated for the treatment of patients with unresectable or
metastatic melanoma at a fixed dose of 200 mg every three weeks until
disease progression or unacceptable toxicity.

Lung Cancer

KEYTRUDA, as a single agent, is indicated for the first-line treatment
of patients with metastatic non-small cell lung cancer (NSCLC) whose
tumors have high PD-L1 expression [tumor proportion score (TPS) ≥50%] as
determined by an FDA-approved test, with no EGFR or ALK genomic tumor
aberrations.

KEYTRUDA, as a single agent, is also 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, in combination with pemetrexed and carboplatin, is indicated
for the first-line treatment of patients with metastatic nonsquamous
NSCLC. This indication is approved under accelerated approval based on
tumor response rate and progression-free survival. Continued approval
for this indication may be contingent upon verification and description
of clinical benefit in the confirmatory trials.

In metastatic NSCLC, KEYTRUDA (pembrolizumab) is administered at a fixed
dose of 200 mg every three weeks until disease progression, unacceptable
toxicity, or up to 24 months in patients without disease progression.

When administering KEYTRUDA in combination with chemotherapy, KEYTRUDA
should be administered prior to chemotherapy when given on the same day.
See also the Prescribing Information for pemetrexed and carboplatin.

Head and Neck Cancer

KEYTRUDA is indicated for the treatment of patients with recurrent or
metastatic head and neck squamous cell carcinoma (HNSCC) with disease
progression on or after platinum-containing chemotherapy. 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. In HNSCC, KEYTRUDA is
administered at a fixed dose of 200 mg every three weeks until disease
progression, unacceptable toxicity, or up to 24 months in patients
without disease progression.

Classical Hodgkin Lymphoma

KEYTRUDA is indicated for the treatment of adult and pediatric patients
with refractory classical Hodgkin lymphoma (cHL), or who have relapsed
after three or more prior lines of therapy. 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. In adults with cHL, KEYTRUDA is administered at a
fixed dose of 200 mg every three weeks until disease progression or
unacceptable toxicity, or up to 24 months in patients without disease
progression. In pediatric patients with cHL, KEYTRUDA is administered at
a dose of 2 mg/kg (up to a maximum of 200 mg) every three weeks until
disease progression or unacceptable toxicity, or up to 24 months in
patients without disease progression.

Urothelial Carcinoma

KEYTRUDA is indicated for the treatment of patients with locally
advanced or metastatic urothelial carcinoma who are not eligible for
cisplatin-containing chemotherapy. This indication is approved under
accelerated approval based on tumor response rate and duration of
response. Continued approval for this indication may be contingent upon
verification and description of clinical benefit in the confirmatory
trials.

KEYTRUDA is also indicated for the treatment of patients with locally
advanced or metastatic urothelial carcinoma who have disease progression
during or following platinum-containing chemotherapy or within 12 months
of neoadjuvant or adjuvant treatment with platinum-containing
chemotherapy.

In locally advanced or metastatic urothelial carcinoma, KEYTRUDA
(pembrolizumab) is administered at a fixed dose of 200 mg every three
weeks until disease progression or unacceptable toxicity, or up to 24
months in patients without disease progression.

Microsatellite Instability-High (MSI-H) 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 that have progressed following prior treatment and who
  have no satisfactory alternative treatment options, or
• colorectal cancer that has progressed following treatment with
  fluoropyrimidine, oxaliplatin, and irinotecan.

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 MSI-H central
nervous system cancers have not been established.

In adult patients with MSI-H cancer, KEYTRUDA is administered at a fixed
dose of 200 mg every three weeks until disease progression, unacceptable
toxicity, or up to 24 months in patients without disease progression. In
pediatric patients with MSI-H cancer, KEYTRUDA is administered at a dose
of 2 mg/kg (up to a maximum of 200 mg) every three weeks until disease
progression or unacceptable toxicity, or up to 24 months in patients
without disease progression.

Selected Important Safety Information for KEYTRUDA

^®
 (pembrolizumab)

KEYTRUDA can cause immune-mediated pneumonitis, including fatal cases.
Pneumonitis occurred in 94 (3.4%) of 2799 patients receiving KEYTRUDA,
including Grade 1 (0.8%), 2 (1.3%), 3 (0.9%), 4 (0.3%), and 5 (0.1%)
pneumonitis, and occurred more frequently in patients with a history of
prior thoracic radiation (6.9%) compared to those without (2.9%).
Monitor patients for signs and symptoms of pneumonitis. Evaluate
suspected pneumonitis with radiographic imaging. Administer
corticosteroids for Grade 2 or greater pneumonitis. Withhold KEYTRUDA
for Grade 2; permanently discontinue KEYTRUDA for Grade 3 or 4 or
recurrent Grade 2 pneumonitis.

KEYTRUDA can cause immune-mediated colitis. Colitis occurred in 48
(1.7%) of 2799 patients receiving KEYTRUDA, including Grade 2 (0.4%), 3
(1.1%), and 4 (<0.1%) colitis. Monitor patients for signs and symptoms
of colitis. Administer corticosteroids for Grade 2 or greater colitis.
Withhold KEYTRUDA (pembrolizumab) for Grade 2 or 3; permanently
discontinue KEYTRUDA for Grade 4 colitis.

KEYTRUDA can cause immune-mediated hepatitis. Hepatitis occurred in 19
(0.7%) of 2799 patients receiving KEYTRUDA, including Grade 2 (0.1%), 3
(0.4%), and 4 (<0.1%) hepatitis. Monitor patients for changes in liver
function. Administer corticosteroids for Grade 2 or greater hepatitis
and, based on severity of liver enzyme elevations, withhold or
discontinue KEYTRUDA.

KEYTRUDA can cause hypophysitis. Hypophysitis occurred in 17 (0.6%) of
2799 patients receiving KEYTRUDA, including Grade 2 (0.2%), 3 (0.3%),
and 4 (<0.1%) hypophysitis. Monitor patients for signs and symptoms of
hypophysitis (including hypopituitarism and adrenal insufficiency).
Administer corticosteroids and hormone replacement as clinically
indicated. Withhold KEYTRUDA for Grade 2; withhold or discontinue for
Grade 3 or 4 hypophysitis.

KEYTRUDA can cause thyroid disorders, including hyperthyroidism,
hypothyroidism, and thyroiditis. Hyperthyroidism occurred in 96 (3.4%)
of 2799 patients receiving KEYTRUDA, including Grade 2 (0.8%) and 3
(0.1%) hyperthyroidism. Hypothyroidism occurred in 237 (8.5%) of 2799
patients receiving KEYTRUDA, including Grade 2 (6.2%) and 3 (0.1%)
hypothyroidism. Thyroiditis occurred in 16 (0.6%) of 2799 patients
receiving KEYTRUDA, including Grade 2 (0.3%) thyroiditis. Monitor
patients for changes in thyroid function (at the start of treatment,
periodically during treatment, and as indicated based on clinical
evaluation) and for clinical signs and symptoms of thyroid disorders.
Administer replacement hormones for hypothyroidism and manage
hyperthyroidism with thionamides and beta-blockers as appropriate.
Withhold or discontinue KEYTRUDA for Grade 3 or 4 hyperthyroidism.

KEYTRUDA can cause type 1 diabetes mellitus, including diabetic
ketoacidosis, which have been reported in 6 (0.2%) of 2799 patients.
Monitor patients for hyperglycemia or other signs and symptoms of
diabetes. Administer insulin for type 1 diabetes, and withhold KEYTRUDA
and administer antihyperglycemics in patients with severe hyperglycemia.

KEYTRUDA can cause immune-mediated nephritis. Nephritis occurred in 9
(0.3%) of 2799 patients receiving KEYTRUDA, including Grade 2 (0.1%), 3
(0.1%), and 4 (<0.1%) nephritis. Monitor patients for changes in renal
function. Administer corticosteroids for Grade 2 or greater nephritis.
Withhold KEYTRUDA for Grade 2; permanently discontinue KEYTRUDA for
Grade 3 or 4 nephritis.

KEYTRUDA can cause other clinically important immune-mediated adverse
reactions. These immune-mediated reactions may occur in any organ
system. For suspected immune-mediated adverse reactions, ensure adequate
evaluation to confirm etiology or exclude other causes. Based on the
severity of the adverse reaction, withhold KEYTRUDA and administer
corticosteroids. Upon improvement to Grade 1 or less, initiate
corticosteroid taper and continue to taper over at least 1 month. Based
on limited data from clinical studies in patients whose immune-related
adverse reactions could not be controlled with corticosteroid use,
administration of other systemic immunosuppressants can be considered.
Resume KEYTRUDA (pembrolizumab) when the adverse reaction remains at
Grade 1 or less following corticosteroid taper. Permanently discontinue
KEYTRUDA for any Grade 3 immune-mediated adverse reaction that recurs
and for any life-threatening immune-mediated adverse reaction.

The following clinically significant immune-mediated adverse reactions
occurred in less than 1% (unless otherwise indicated) of 2799 patients:
arthritis (1.5%), exfoliative dermatitis, bullous pemphigoid, rash
(1.4%), uveitis, myositis, Guillain-Barré syndrome, myasthenia gravis,
vasculitis, pancreatitis, hemolytic anemia, and partial seizures arising
in a patient with inflammatory foci in brain parenchyma. In addition,
myelitis and myocarditis were reported in other clinical trials,
including classical Hodgkin lymphoma, and postmarketing use.

Solid organ transplant rejection has been reported in postmarketing use
of KEYTRUDA. Treatment with KEYTRUDA may increase the risk of rejection
in solid organ transplant recipients. Consider the benefit of treatment
with KEYTRUDA vs the risk of possible organ rejection in these patients.

KEYTRUDA can cause severe or life-threatening infusion-related
reactions, including hypersensitivity and anaphylaxis, which have been
reported in 6 (0.2%) of 2799 patients. Monitor patients for signs and
symptoms of infusion-related reactions, including rigors, chills,
wheezing, pruritus, flushing, rash, hypotension, hypoxemia, and fever.
For Grade 3 or 4 reactions, stop infusion and permanently discontinue
KEYTRUDA.

Immune-mediated complications, including fatal events, occurred in
patients who underwent allogeneic hematopoietic stem cell
transplantation (HSCT) after being treated with KEYTRUDA. Of 23 patients
with cHL who proceeded to allogeneic HSCT after treatment with KEYTRUDA
on any trial, 6 patients (26%) developed graft-versus-host-disease
(GVHD), one of which was fatal, and 2 patients (9%) developed severe
hepatic veno-occlusive disease (VOD) after reduced-intensity
conditioning, one of which was fatal. Cases of fatal hyperacute GVHD
after allogeneic HSCT have also been reported in patients with lymphoma
who received a PD-1 receptor–blocking antibody before transplantation.
These complications may occur despite intervening therapy between PD-1
blockade and allogeneic HSCT. Follow patients closely for early evidence
of transplant-related complications such as hyperacute GVHD, severe
(Grade 3 to 4) acute GVHD, steroid-requiring febrile syndrome, hepatic
VOD, and other immune-mediated adverse reactions, and intervene promptly.

Based on its mechanism of action, KEYTRUDA (pembrolizumab) can cause
fetal harm when administered to a pregnant woman. If used during
pregnancy, or if the patient becomes pregnant during treatment, apprise
the patient of the potential hazard to a fetus. Advise females of
reproductive potential to use highly effective contraception during
treatment and for 4 months after the last dose of KEYTRUDA.

In KEYNOTE-052, KEYTRUDA was discontinued due to adverse reactions in
11% of 370 patients with locally advanced or metastatic urothelial
carcinoma. The most common adverse reactions (in≥20% of patients) were
fatigue (38%), musculoskeletal pain (24%), decreased appetite (22%),
constipation (21%), rash (21%), and diarrhea (20%). Eighteen patients
(5%) died from causes other than disease progression. Five patients
(1.4%) who were treated with KEYTRUDA experienced sepsis which led to
death, and 3 patients (0.8%) experienced pneumonia which led to death.
Adverse reactions leading to interruption of KEYTRUDA occurred in 22% of
patients; the most common (≥1%) were liver enzyme increase, diarrhea,
urinary tract infection, acute kidney injury, fatigue, joint pain, and
pneumonia. Serious adverse reactions occurred in 42% of patients, the
most frequent (≥2%) of which were urinary tract infection, hematuria,
acute kidney injury, pneumonia, and urosepsis.

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%). Adverse reactions
leading to interruption of KEYTRUDA occurred in 20% of patients; the
most common (≥1%) were urinary tract infection (1.5%), diarrhea (1.5%),
and colitis (1.1%). The most common adverse reactions (20%) in patients
who received KEYTRUDA vs those who received chemotherapy were fatigue
(38% vs 56%), musculoskeletal pain (32% vs 27%), pruritus (23% vs 6%),
decreased appetite (21% vs 21%), nausea (21% vs 29%), and rash (20% vs
13%). Serious adverse reactions occurred in 39% of KEYTRUDA-treated
patients, the most frequent (≥2%) of which were urinary tract infection,
pneumonia, anemia, and pneumonitis.

It is not known whether KEYTRUDA is excreted in human milk. Because many
drugs are excreted in human milk, instruct women to discontinue nursing
during treatment with KEYTRUDA and for 4 months after the final dose.

Our Focus on Cancer

Our goal is to translate breakthrough science into innovative oncology
medicines to help people with cancer worldwide. At Merck, helping people
fight cancer is our passion and supporting accessibility to our cancer
medicines is our commitment. Our focus is on pursuing research in
immuno-oncology and we are accelerating every step in the journey – from
lab to clinic – to potentially bring new hope to people with cancer.

As part of our focus on cancer, Merck is committed to exploring the
potential of immuno-oncology with one of the fastest-growing development
programs in the industry. We are currently executing an expansive
research program that includes more than 500 clinical trials evaluating
our anti-PD-1 therapy across more than 30 tumor types. We also continue
to strengthen our immuno-oncology portfolio through strategic
acquisitions and are prioritizing the development of several promising
immunotherapeutic candidates with the potential to improve the treatment
of advanced cancers.

For more information about our oncology clinical trials, visit www.merck.com/clinicaltrials.

About Merck

For more than a century, Merck, a leading global biopharmaceutical
company known as MSD outside of the United States and Canada, has been
inventing for life, bringing forward medicines and vaccines for many of
the world’s most challenging diseases. Through our prescription
medicines, vaccines, biologic therapies and animal health products, we
work with customers and operate in more than 140 countries to deliver
innovative health solutions. We also demonstrate our commitment to
increasing access to health care through far-reaching policies, programs
and partnerships. Today, Merck continues to be at the forefront of
research to advance the prevention and treatment of diseases that
threaten people and communities around the world – including cancer,
cardio-metabolic diseases, emerging animal diseases, Alzheimer’s disease
and infectious diseases including HIV and Ebola. For more information,
visit www.merck.com
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Please see Prescribing Information for KEYTRUDA (pembrolizumab) at 

http://www.merck.com/product/usa/pi_circulars/k/keytruda/keytruda_pi.pdf

 and

Patient Information/Medication Guide for KEYTRUDA at 

http://www.merck.com/product/usa/pi_circulars/k/keytruda/keytruda_mg.pdf

.

Merck & Co., Inc.
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