Merck & Co., Inc announces Phase III trial results for letermovir to prevent clinically-significant cytomegalovirus (CMV) infection.

Merck & Co., Inc. has announced that the pivotal Phase III 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 (CMV) infection in adult (18 years and older) CMV-seropositive recipients of an allogeneic hematopoietic stem cell transplant (HSCT) .

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. Data were not posted, but these will come at a future scientific conference, according to the company.