Merck & Co. and Dynavax Technologies have entered into two clinical trial collaboration agreements to investigate the potential synergistic effect of combining immunotherapies from both companies' pipelines: Merck's anti-PD-1 therapy, Keytruda (pembrolizumab), and its investigational anti-interleukin-10 (anti-IL-10) immunomodulator, MK-1966, with Dynavax's investigational toll-like receptor 9 (TLR9) agonist, SD-101.

SD-101, Keytruda and MK-1966 are immunotherapies designed to enhance the body's own defenses in fighting cancer. SD-101 is designed to mediate anti-tumor effects by triggering both innate and adaptive immune responses, including the induction of high levels of type 1 interferon to stimulate recruitment of T-cells. Keytruda is a humanized monoclonal antibody that blocks the interaction between PD-1 (programmed death receptor-1) and its ligands, PD-L1 and PD-L2. MK-1966 is an investigational anti-IL-10 immunomodulator designed to neutralize the immune-suppressive environment for tumors. The collaboration includes multiple studies that will evaluate:

• Safety and efficacy of combining SD-101 with Keytruda in patients with advanced melanoma; this phase Ib/II, multicenter, open-label study is expected to be initiated in the second half of 2015.
• Safety and efficacy of combining SD-101 with MK-1966 in patients with solid or hematological malignancies; this phase I study is expected to be initiated in the second half of 2015.

Dynavax will sponsor and fund the SD-101 and Keytruda study. Merck will sponsor and fund the SD-101 and MK-1966 study. The agreements include provisions where the parties may agree to extend either collaboration to include a phase III clinical trial. Additional details of the agreements between Dynavax and Merck, through a subsidiary, were not disclosed.