The Phase III study evaluating Merck & Co. ’ s prophylactic antiviral candidate letermovir met its main and secondary endpoints of preventing the development of significant cytomegalovirus (CMV) infection in patients receiving an allogeneic hematopoietic stem cell transplant (HSCT). The firm says this plans to submit regulatory applications for letermovir within the EU and U. S. later this year.

The placebo-controlled Phase III study enrolled adult CMV-seropositive HSCT individuals who had undetectable plasma CMV DNA. Letermovir treatment was started within the first 28 days following HSCT. The data showed that of the 495 patients who got undetectable CMV DNA at the start of the treatment, 37. 5% of patients in the letermovir arm developed clinically substantial CMV infection through to week 14, compared with 60. 6% of patients in the placebo arm. The study also fulfilled its secondary endpoints, showing that significantly fewer sufferers in the letermovir arm (19. 1%) developed clinically substantial CMV…