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December 11, 2017 6:30 am ET

Data for KEYTRUDA in Patients with Relapsed or Refractory PMBCL Show Overall Response Rate of 41 Percent in Difficult-to-Treat Patient Population

Findings from KEYNOTE-170 Presented at 59th American Society of Hematology (ASH) Annual Meeting

Merck (NYSE: MRK), known as MSD outside the United States and Canada,
today announced findings from the phase 2 KEYNOTE-170 trial
investigating the use of KEYTRUDA^® (pembrolizumab), the
company’s anti-PD-1 therapy, in the cohort of patients with relapsed or
refractory primary mediastinal large B-cell lymphoma (PMBCL), a type of
non-Hodgkin lymphoma. In the PMBCL cohort of KEYNOTE-170, KEYTRUDA
demonstrated an overall response rate (ORR) of 41 percent (n=12/29),
including a 24 percent (n=7/29) complete response rate and a 17 percent
(n=5/29) partial response rate, in patients who relapsed after or were
refractory to autologous stem cell transplant (ASCT), or were ineligible
for ASCT and failed two or more prior lines of therapy. These data were
presented at the 59th American Society of Hematology (ASH) Annual
Meeting in Atlanta on Sunday, Dec. 10 (Abstract #2833).

“There is a significant unmet need for patients with relapsed or
refractory primary mediastinal large B-cell lymphoma,” said Pier Luigi
Zinzani, M.D., Ph.D., associate professor of hematology, Institute of
Hematology “L. e A. Seràgnoli,” University of Bologna. “These
encouraging results represent another step in understanding the
potential of KEYTRUDA to help these patients who have already tried and
progressed on prior therapies.”

Based on data from KEYNOTE-170 and the phase 1b KEYNOTE-013 trial, which
is evaluating the safety, tolerability and efficacy of KEYTRUDA
monotherapy in patients with various blood cancers, the U.S. Food and
Drug Administration (FDA) has accepted for review a supplemental
Biologics License Application (sBLA) for KEYTRUDA (pembrolizumab) for
the treatment of adult and pediatric patients with refractory primary
mediastinal B-cell lymphoma, or who have relapsed after two or more
prior lines of therapy. The FDA granted Priority Review status with a
PDUFA, or target action, date of April 3, 2018. In January 2017,
KEYTRUDA was granted Breakthrough Therapy Designation by the FDA for
this indication.

“These findings in patients with PMBCL are promising for a rare lymphoma
that affects mainly young adults and has few effective treatment options
in the relapsed or refractory treatment setting,” said Dr. Roger Dansey,
senior vice president and therapeutic area head, oncology late-stage
development, Merck Research Laboratories. “If approved by the FDA, this
would be our second blood cancer indication for KEYTRUDA, following FDA
approval for certain patients with classical Hodgkin Lymphoma earlier
this year. The acceptance of our sBLA reinforces our ongoing commitment
to finding new treatment advances in hematology.”

The KEYTRUDA hematology program includes more than 50 ongoing studies –
including company sponsored, investigator sponsored and collaborative
studies; several of these are registration-enabling trials.

Data from KEYNOTE-170 at ASH (Abstract #2833)

KEYNOTE-170 is an ongoing, non-randomized, two-cohort, multicenter,
phase 2 study evaluating the efficacy and safety of KEYTRUDA (200 mg
fixed dose every three weeks) in patients with relapsed or refractory
PMBCL and in patients with relapsed or refractory Richter syndrome. The
PMBCL cohort enrolled patients who relapsed after or were refractory to
ASCT, or were ineligible for ASCT; patients ineligible for ASCT had to
have relapsed or refractory disease after two or more lines of prior
therapy. The primary endpoint was ORR by blinded independent central
review; key secondary endpoints included duration of response and safety
and tolerability.

In the efficacy population (n=29), ORR was 41 percent (n=12) (95% CI,
24-61), with a complete response rate of 24 percent (n=7) (95% CI,10-44)
and a partial response rate of 17 percent (n=5) (95% CI, 6-36). Median
duration of follow-up was 10.5 months (range: 0.1-17.7). Median time to
response was 2.8 months (range: 2.4-5.5). Median duration of response
was not reached (range: 1.1+ to 13.6+ months).

Treatment-related adverse events (TRAEs) were consistent with previously
reported safety data for KEYTRUDA. Of the 53 patients evaluated for
safety, 57 percent (n=30) experienced TRAEs, including 21 percent (n=11)
who experienced Grade 3-4 TRAEs. The most common TRAEs (greater than or
equal to 5%) were neutropenia (n=11), hypothyroidism (n=4), asthenia
(n=3) and pyrexia (n=3). Immune-mediated adverse events of all grades
occurred in 11 percent (n=6) of patients; these include hypothyroidism
(n=4), hyperthyroidism (n=2), pneumonitis (n=1) and thyroiditis (n=1).
There were no treatment-related deaths.

About Primary Mediastinal Large B-Cell Lymphoma

PMBCL is a sub-type of diffuse large B-cell lymphoma (a type of
non-Hodgkin lymphoma) that starts in the space between the lungs, called
the mediastinum. PMBCL mainly affects young adults (with a median age of
35), and occurs slightly more often in women. PMBCL accounts for two to
four percent of all non-Hodgkin lymphomas in the U.S.

About KEYTRUDA

^®

(pembrolizumab) Injection
100mg

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.

Merck has the industry’s largest immuno-oncology clinical research
program, which currently involves more than 650 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.

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
(pembrolizumab).

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 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 (pembrolizumab) 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 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
children 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.

Gastric Cancer

KEYTRUDA is indicated for the treatment of patients with recurrent
locally advanced or metastatic gastric or gastroesophageal junction
(GEJ) adenocarcinoma whose tumors express PD-L1 [Combined Positive Score
(CPS) ≥1] as determined by an FDA-approved test, with disease
progression on or after two or more prior lines of therapy including
fluoropyrimidine- and platinum-containing chemotherapy and if
appropriate, HER2/neu-targeted 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. The recommended dose of KEYTRUDA (pembrolizumab) is
200 mg every three weeks until disease progression, 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 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. The incidence of new or worsening hypothyroidism was
higher in patients with HNSCC, occurring in 28 (15%) of 192 patients
with HNSCC, including Grade 3 (0.5%) hypothyroidism. Thyroiditis
occurred in 16 (0.6%) of 2799 patients receiving KEYTRUDA
(pembrolizumab), 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.

Immune-mediated rashes, including Stevens-Johnson syndrome (SJS), toxic
epidermal necrolysis (TEN) (some cases with fatal outcome), exfoliative
dermatitis, and bullous pemphigoid, can occur. Monitor patients for
suspected severe skin reactions and based on the severity of the adverse
reaction, withhold or permanently discontinue KEYTRUDA and administer
corticosteroids. For signs or symptoms of SJS or TEN, withhold KEYTRUDA
and refer the patient for specialized care for assessment and treatment.
If SJS or TEN is confirmed, permanently discontinue KEYTRUDA.

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 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%), 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 (pembrolizumab). 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.

In clinical 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 a PD-1 or PD-L1
blocking antibody in this combination is not recommended outside of
controlled clinical trials.

Based on its mechanism of action, KEYTRUDA 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-006, KEYTRUDA was discontinued due to adverse reactions in 9%
of 555 patients with advanced melanoma; adverse reactions leading to
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%). Adverse reactions leading to interruption of
KEYTRUDA (pembrolizumab) occurred in 21% of patients; the most common
(≥1%) was diarrhea (2.5%). The most common adverse reactions with
KEYTRUDA vs ipilimumab were fatigue (28% vs 28%), diarrhea (26% with
KEYTRUDA), rash (24% vs 23%), and nausea (21% with KEYTRUDA).
Corresponding incidence rates are listed for ipilimumab only for those
adverse reactions that occurred at the same or lower rate than with
KEYTRUDA.

In KEYNOTE-010, KEYTRUDA monotherapy was discontinued due to adverse
reactions in 8% of 682 patients with metastatic NSCLC. The most common
adverse event resulting in permanent discontinuation of KEYTRUDA was
pneumonitis (1.8%). Adverse reactions leading to interruption of
KEYTRUDA occurred in 23% of patients; the most common (≥1%) were
diarrhea (1%), fatigue (1.3%), pneumonia (1%), liver enzyme elevation
(1.2%), decreased appetite (1.3%), and pneumonitis (1%). The most common
adverse reactions (occurring in at least 20% of patients and at a higher
incidence than with docetaxel) were decreased appetite (25% vs 23%),
dyspnea (23% vs 20%), and nausea (20% vs 18%).

In KEYNOTE-021(G1), when KEYTRUDA was administered in combination with
carboplatin and pemetrexed (carbo/pem) in advanced nonsquamous NSCLC,
KEYTRUDA was discontinued in 10% of 59 patients. The most common adverse
reaction resulting in discontinuation of KEYTRUDA (≥2%) was acute kidney
injury (3.4%). Adverse reactions leading to interruption of KEYTRUDA
occurred in 39% of patients; the most common (≥2%) were fatigue (8%),
neutrophil count decreased (8%), anemia (5%), dyspnea (3.4%), and
pneumonitis (3.4%).The most common adverse reactions (≥20%) with
KEYTRUDA compared to carbo/pem alone were fatigue (71% vs 50%), nausea
(68% vs 56%), constipation (51% vs 37%), rash (42% vs 21%), vomiting
(39% vs 27%), dyspnea (39% vs 21%), diarrhea (37% vs 23%), decreased
appetite (31% vs 23%), headache (31% vs 16%), cough (24% vs 18%),
dizziness (24% vs 16%), insomnia (24% vs 15%), pruritus (24% vs 4.8%),
peripheral edema (22% vs 18%), dysgeusia (20% vs 11%), alopecia (20% vs
3.2%), upper respiratory tract infection (20% vs 3.2%), and arthralgia
(15% vs 24%). This study was not designed to demonstrate a statistically
significant difference in adverse reaction rates for KEYTRUDA as
compared to carbo/pem alone for any specified adverse reaction.

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 (reported in at least 20% of patients) 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, with the exception of increased incidences of facial
edema (10% all Grades; 2.1% Grades 3 or 4) and new or worsening
hypothyroidism.

In KEYNOTE-087, KEYTRUDA (pembrolizumab) was discontinued due to adverse
reactions in 5% of 210 patients with cHL, and treatment was interrupted
due to adverse reactions in 26% of patients. Fifteen percent (15%) of
patients had an adverse reaction requiring systemic corticosteroid
therapy. Serious adverse reactions occurred in 16% of patients. The most
frequent serious adverse reactions (≥1%) included pneumonia,
pneumonitis, pyrexia, dyspnea, GVHD, and herpes zoster. Two patients
died from causes other than disease progression; one from GVHD after
subsequent allogeneic HSCT and one from septic shock. The most common
adverse reactions (occurring in ≥20% of patients) were fatigue (26%),
pyrexia (24%), cough (24%), musculoskeletal pain (21%), diarrhea (20%),
and rash (20%).

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.

There is limited experience in pediatric patients. In a study, 40
pediatric patients (16 children aged 2 years to younger than 12 years
and 24 adolescents aged 12 years to 18 years) with advanced melanoma,
lymphoma, or PD-L1–positive advanced, relapsed, or refractory solid
tumors were administered KEYTRUDA (pembrolizumab) 2 mg/kg every 3 weeks.
Patients received KEYTRUDA for a median of 3 doses (range 1–17 doses),
with 34 patients (85%) receiving KEYTRUDA for 2 doses or more. The
safety profile in these pediatric patients was similar to that seen in
adults treated with KEYTRUDA. Toxicities that occurred at a higher rate
(≥15% difference) in these patients when compared to adults under 65
years of age were fatigue (45%), vomiting (38%), abdominal pain (28%),
hypertransaminasemia (28%), and hyponatremia (18%).

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 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.

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company known as MSD outside of the United States and Canada, has been
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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 2016 Annual Report on Form 10-K
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


Patient Information/Medication Guide for KEYTRUDA at 

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

.

Merck
Media:
Pamela Eisele, 267-305-3558
Elizabeth Sell, 267-305-3877
or
Investors:
Teri Loxam, 908-740-1986
Amy Klug, 908-740-1898