Additional Interim Data for Merck’s Investigational Anti-PD-1 Immunotherapy, MK-3475, Shows Estimated Overall Survival Rate of

  Additional Interim Data for Merck’s Investigational Anti-PD-1 Immunotherapy,
  MK-3475, Shows Estimated Overall Survival Rate of 81 Percent at One Year in
  Patients with Advanced Melanoma

Business Wire

WHITEHOUSE STATION, N.J. -- November 18, 2013

Merck (NYSE:MRK), known as MSD outside the United States and Canada, today
announced additional data for MK-3475, an investigational anti-PD-1
immunotherapy, in patients with advanced melanoma that showed an estimated
overall survival rate of 81 percent at one year across all MK-3475 monotherapy
doses evaluated. This is the first time overall survival datahave been
presented from the cohort of 135 patients with advanced melanoma enrolled in
Merck’s ongoing Phase IB clinical trial (PN 001) for MK-3475. Researchers
presented the findings today in an oral plenary session at the 10th
International Congress of the Society for Melanoma Research in Philadelphia.

“New agents are needed for patients with advanced melanoma,” said Dr. Caroline
Robert, head of Dermatology at Gustave Roussy, Cancer Campus, Grand Paris. “I
am excited by the results seen for MK-3475 to date as a single agent and
believe these findings support further study both as a monotherapy and in
combination in various solid tumors.”

The objective response rate (patients who had either a complete or partial
response) across all doses improved with longer duration of follow-up; at the
time of this analysis, the objective response rate was 41 percent (9 percent
complete response rate), as evaluated by a blinded central review committee
using RECIST 1.1 (Response Evaluation Criteria in Solid Tumors). While the
majority of responses to MK-3475 treatment occurred early (within the first 12
weeks), responses and changes from partial to complete response continued to
occur after six months of treatment. Partial and complete responses occurred
as late as 48 and 70 weeks. Median duration of response and median overall
survival have yet to be reached for any dose evaluated.

“These results provide further insight into the therapeutic properties of
MK-3475 in patients with advanced melanoma,” said Dr. Roger M. Perlmutter,
president, Merck Research Laboratories. “Simply put, our data make us hopeful
that this novel investigational therapy could potentially provide meaningful
benefits to patients suffering from this malignant disease.”

Phase 1B Trial (PN 001) Trial Design

The Phase IB trial (PN 001) is an ongoing multi-center, single-arm, open-label
study evaluating MK-3475 monotherapy in more than 1,000 patients with diverse
late-stage cancers (metastatic carcinoma)—predominantly lung and melanoma.
Three dosing regimens of MK-3475 were evaluated, including 10mg/kg every two
weeks, 10mg/kg every three weeks or 2mg/kg every three weeks. The primary
endpoint of the study is overall response rate and the secondary endpoints are
progression-free survival and overall survival as measured by immune-related
response criteria and centrally evaluated RECIST criteria.

Additional Results for MK-3475 in Advanced Melanoma

This additional analysis provides approximately five months of follow-up for
objective response rate beyond the interim results for MK-3475 from the 135
patients in the advanced melanoma cohort presented at the 2013 American
Society of Clinical Oncology (ASCO) Annual meeting and published in the New
England Journal of Medicine.In addition, this is the first time overall
survival and progression-free survival have been presented from this study.

The previously reported objective response rate across all doses was 38
percent (CI 95%: 25 to 44 percent) (per RECIST criteria).In the analysis
presented today, the overall response rate was 41 percent (CI 95%: 32 to 51
percent), reflecting additional responses to MK-3475. In addition, 88 percent
(43/49) of patients with a partial or complete response showed no evidence of
disease progression. Similar response rates were observed between
ipilimumab-pretreated and ipilimumab-naïve patients.

At this analysis, the maximum ongoing duration of response recorded was 65
weeks (range 8+ to 65+). The disease control rate across doses for patients in
the melanoma cohort was 61 percent (CI 95%: 52 to 70 percent), and median
progression-free survival at time of analysis was 36 weeks. The rates of
treatment-related adverse events were consistent with those previously
observed and included: fatigue (37%), pruritus (26%), rash (22%), diarrhea
(21%), arthralgia (17%), vitiligo (14%), headache (13%), nausea (12%),
asthenia (11%), myalgia (11%) and AST increase (10%). Grade 3–4
treatment-related adverse events that occurred in more than one patient were
AST increase, fatigue, rash and renal failure (n=2 each).

Clinical Development of MK-3475 in Advanced Melanoma

Merck has completed enrollment in a Phase II registration trial (PN 002)
comparing two doses of MK-3475 versus chemotherapy in patients with advanced
melanoma who have progressed after prior therapy (see A
Phase III registration trial of MK-3475 versus ipilimumab in ipilimumab-naïve
patients with advanced melanoma is ongoing (see The
company plans to initiate combination trials this year and in early 2014 in
melanoma and other cancers.

About MK-3475

Many tumors are able to evade the immune system through a mechanism that
exploits the PD-1 inhibitory checkpoint protein. MK-3475 is an
investigational, highly selective anti-PD-1 immunotherapy designed to restore
the natural ability of the immune system to recognize and target cancer cells
by selectively achieving dual ligand blockade (PD-L1 and PD-L2) of the PD-1
protein. By blocking PD-1, MK-3475 enables activation of the immune system’s
T-cells that target cancer by essentially releasing a brake on the immune

MK-3475 is currently being studied in eight clinical trials estimated to
enroll over 3,000 patients across a broad range of cancer types, including:
bladder, colorectal, gastric, head and neck, melanoma, non-small cell lung,
triple negative breast and hematological malignancies. Additional trials, both
as monotherapy and in combination with other cancer therapies, are planned.
The expansion of the MK-3475 clinical development program is based on
preliminary clinical evidence from Merck’s large foundational Phase IB trial
(PN 001) evaluating MK-3475 monotherapy in more than 1,000 patients with
diverse late-stage cancers (metastatic carcinoma).

About Breakthrough Therapy Designation

In April 2013, Merck announced that MK-3475 received a Breakthrough Therapy
Designation for advanced melanoma from the U.S. Food and Drug Administration
(FDA). This designation for an investigational drug is intended to expedite
the development and review of a candidate that is planned for use, alone or in
combination, to treat a serious or life-threatening disease or condition when
preliminary clinical evidence indicates that the drug may demonstrate
substantial improvement over existing therapies on one or more clinically
significant endpoints. The U.S. FDA Safety and Innovation Act includes a
provision that allows sponsors to request that an investigational drug be
designated as a Breakthrough Therapy.

About Advanced Melanoma

Over one million new cases of skin cancer are diagnosed each year, and
melanoma is the most dangerous type of skin cancer. While it accounts for only
5 percent of all cases, melanoma is the cause of 75 percent of skin cancer
deaths. According to the American Cancer Society, an estimated 9,180 people in
the U.S. died from advanced melanoma in 2012.

About Merck

Today's Merck is a global healthcare leader working to help the world be well.
Merck is known as MSD outside the United States and Canada. Through our
prescription medicines, vaccines, biologic therapies, and consumer care 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 healthcare through far-reaching policies,
programs and partnerships. For more information, visit and
connect with us on Twitter, Facebook and YouTube.

Merck Forward-Looking Statement

This news release includes “forward-looking statements” within the meaning of
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Reform Act of 1995. These statements are based upon the current beliefs and
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Risks and uncertainties include, but are not limited to, general industry
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Merck 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 Merck’s 2012
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


Ian McConnell, 908-423-3046
Claire Mulhearn, 908-423-7425
Carol Ferguson, 908-423-4465
Justin Holko, 908-423-5088
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