FDA approves Prevymis for prophylaxis of cytomegalovirus infection

Prevymis (letermovir), once-daily tablets for oral use and injection for intravenous infusion, is indicated for prophylaxis (prevention) of cytomegalovirus (CMV) infection and disease in adult CMV-seropositive recipients [R+] of an allogeneic hematopoietic stem cell transplant (HSCT). CMV is a common and potentially serious viral infection in allogeneic HSCT recipients. CMV-seropositive patients who undergo an HSCT are at high risk for CMV reactivation. Any level of CMV infection is associated with increased mortality in HSCT patients.

In the pivotal Phase III clinical trial supporting approval, significantly fewer patients in the Prevymis group (38%, n=122/325) compared to the placebo group (61%, n=103/170) developed clinically significant CMV infection, discontinued treatment or had missing data through Week 24 post-HSCT [treatment difference: -23.5 (95% confidence interval -32.5 to -14.6), (p<0.0001)], the primary efficacy endpoint. All-cause mortality in patients receiving Prevymis was lower compared to placebo, 12% vs. 17%, respectively, at week 24 post-transplant. In this study, the incidence of bone marrow suppression in the Prevymis group was comparable to the placebo group. The median time to engraftment was 19 days in the Prevymis group and 18 days in the placebo group.

Comment: Though CMV is harmless to most people, it can be deadly to patients who have received bone marrow transplants. Given for up to 100 days after a transplant, Prevymis is designed to fend off infection and prevent reactivation in patients who already carry the virus.