Chimerix

CMX157

Chimerix Signs Worldwide License Agreement with Merck for CMX157, A Novel Candidate for the Treatment of HIV

RESEARCH TRIANGLE PARK, NC – July 24, 2012 – Chimerix, Inc. today announced the execution of a license agreement granting Merck, known as MSD outside the United States and Canada, exclusive worldwide rights to CMX157, Chimerix's novel lipid acyclic nucleoside phosphonate currently being evaluated to treat HIV infection.

Under the terms of the agreement, Merck receives an exclusive worldwide license and will be responsible for development and commercialization of CMX157, an investigational oral nucleoside reverse transcriptase inhibitor (NRTI). Chimerix will receive a $17.5 million upfront payment and will be eligible to receive up to $151 million in milestones, as well as royalties on future sales.

"This agreement is a significant milestone in Chimerix's mission of developing best-in-class therapies for major unmet medical needs based on our lipid technology platform," said Kenneth I. Moch, President and CEO of Chimerix. "Merck is the ideal collaborator to develop this drug and help us to maximize the potential of CMX157, given its commitment to its HIV franchise. The value created through the licensure of CMX157 will help us continue to advance our lead compound, CMX001, through its critical Phase 3 trial, for which we currently plan to begin enrolling patients early next year."

"Merck is committed to bringing forward new treatment options for patients with HIV/AIDs," said Daria Hazuda, Vice President and Worldwide Discovery Head for Infectious Diseases, Merck Research Laboratories. "We look forward to working closely with Chimerix to advance development of this NRTI candidate."

About CMX157

CMX157 is a novel lipid acyclic nucleoside phosphonate that delivers high intracellular concentrations of the active antiviral agent tenofovir diphosphate. CMX157 is more than 200-fold more potent in vitro versus tenofovir against all major HIV subtypes resistant to current therapies, which may allow activity against tenofovir-resistant viruses (e.g., K65R), and against HBV. CMX157's novel structure results in decreased circulating levels of tenofovir, lowering systemic exposure and thereby reducing the potential for renal side effects. CMX157 has completed a Phase 1 clinical trial in healthy volunteers, demonstrating a favorable safety, tolerability and drug distribution profile.