Merck Announces Breakthrough Therapy Designation for Lambrolizumab an Investigational Antibody Therapy for Advanced Melanoma

WHITEHOUSE STATION, N.J.--Merck (NYSE: MRK), known as MSD outside the United States and Canada, announced today that the U.S. Food and Drug Administration (FDA) has designated lambrolizumab (MK-3475) as a Breakthrough Therapy for the treatment of patients with advanced melanoma. Lambrolizumab is Merck's investigational antibody therapy targeting Programmed Death receptor (PD-1) that is currently being evaluated for the treatment of patients with advanced melanoma, and other tumor types.

"We are pleased that the FDA has designated lambrolizumab a Breakthrough Therapy for patients with advanced melanoma," said Gary Gilliland M.D., Ph.D., senior vice president and oncology franchise head, Merck Research Laboratories. "The FDA's decision to place lambrolizumab in a category that may enable expedited development and review is an important milestone for Merck as we advance ongoing programs in multiple cancer indications."

The designation of an investigational drug as a Breakthrough Therapy 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 Food and Drug Administration Safety and Innovation Act (FDASIA) includes a provision that allows sponsors to request that an investigational drug be designated as a Breakthrough Therapy. The implications of Breakthrough Therapy Designation cannot be determined at this time.

In November 2012, early interim results from a single-arm, open-label Phase Ib study of lambrolizumab (MK-3475) administered to 85 patients with advanced (inoperable and metastatic) melanoma were presented at the Society for Melanoma Research of the 9th International Congress of the Society for Melanoma Research (SMR) in Hollywood, Calif. (see news release).

Advanced melanoma

Advanced melanoma accounts for more than 80 percent of skin cancer-related deaths and one to two percent of all cancer deaths in the United States¹. According to the American Cancer Society, in 2012 in the U.S. an estimated 9,180 people died from advanced melanoma.

About PD-1

Researchers have shown that several tumor types are able to hide in plain sight by establishing a "molecular camouflage" that deceives the body's immune system into thinking they are normal and therefore allow them to grow unchecked. The interaction between the immune checkpoint receptor PD-1 (programmed death) and its ligands represents a potentially important tumor-specific immunomodulatory mechanism. By utilizing the PD-1 pathway, a tumor cell can prevent the activation of T-cells and therefore may block a key step that triggers the immune system.

About lambrolizumab

Lambrolizumab is an investigational antibody therapy designed to disrupt the action of the immune checkpoint protein PD-1 and therefore inhibit the ability of some cancers to evade the body's immune system. Lambrolizumab is being studied in multiple cancer types including melanoma and non-small cell lung cancer. For further details, please visit http://clinicaltrials.gov.

About Merck

Today's Merck is a global healthcare leader working to help the world be well. Merck is known as MSD outside of 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 www.merck.com and connect with us on Twitter, Facebook and YouTube.

Merck forward-Looking Statement

This news release includes "forward-looking statements" within the meaning of the safe harbor provisions of the United States Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of Merck's management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline products that the products 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; Merck'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 Merck's patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

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 (www.sec.gov).

¹http://my.clevelandclinic.org/disorders/skin_cancer/hic_the_facts_about_melanoma.aspx Accessed on April 17, 2013