Merck’s CMV Drug Lowers Reactivation by 88% After Cell Transplant

Merck recently announced that its cytomegalovirus (CMV) treatment, Prevymis (letermovir), lowered the odds of CMV reactivation by 88% 100 days after allogeneic hematopoietic cell transplantation (alloHCT). 

Researchers analyzed 48 real-world observational studies of Prevymis compared to controls (mostly preemptive therapy). All studies enrolled CMV-seropositive patients predominantly in the US, Italy, and Japan undergoing alloHCT. These patients are at a notably higher risk for CMV reactivation.  

Overall, Prevymis lowered the chance for clinically significant CMV infection by 91%, the chance of CMV disease by 69%, and the possibility of Grade 2 or greater graft versus host disease by 48%.  

And researchers noted consistent results at 200 days of follow-up after alloHCT. Specifically, there was a 76% lower possibility of CMV reactivation, an 81% lower chance for clinically significant CMV infection, and a 65% lower chance of CMV disease.  

“CMV reactivation in patients who undergo alloHCT can lead to potentially serious health complications,” Roy Chemaly, MD, director of the clinical virology research program at the University of Texas MD Anderson Cancer Center, said in the announcement.  

“This analysis of real-world effectiveness of letermovir builds upon the evidence from the Phase 3 clinical trial in which letermovir as prophylaxis reduced the risk of CMV infection in CMV-seropositive patients. This new analysis also provides data on the potential of letermovir to reduce the odds of CMV-related hospitalization and graft versus host disease,” Chemaly continued.  

CMV is a common virus, and most infected healthy people may experience no symptoms. But once infected, the body retains CMV for life. CMV is related to the viruses that cause chickenpox, herpes simplex, and mononucleosis. 

In November 2017, FDA approved Prevymis once-daily tablets for CMV prevention in CMV-seropositive recipients of an allogeneic hematopoietic stem cell transplant (HSCT).  

At the time, a Phase 3 clinical trial found that significantly fewer patients in the Prevymis group (38%) developed clinically significant CMV infection, discontinued treatment, or had missing data through week 24 post-HSCT than the placebo group (61%).