Merck says Phase 3 letermovir study met primary endpoint
Merck & Co. announced that the pivotal Phase 3 clinical study of letermovir, an investigational antiviral medicine, met its primary endpoint. The global, multicenter, randomized, placebo-controlled study evaluated the efficacy and safety of letermovir for the prevention of clinically-significant cytomegalovirus infection in adult CMV-seropositive recipients of an allogeneic hematopoietic stem cell transplant. Merck will submit results from the study for presentation at a future scientific conference. In the study, letermovir was administered once daily, either in oral tablet or IV formulation. Letermovir was started as early as the day of HSCT transplant and no later than 28 days post-transplant, and continued through approximately 100 days after transplant. The primary outcome measure was the percentage of participants with clinically-significant CMV infection through 24 weeks after transplant. Under an agreement signed in 2012, Merck purchased worldwide rights to develop and commercialize letermovir from AiCuris GmbH & Co KG.