Long before, a significant number of experts have regarded cytomegalovirus (CMV) infections as a kind of herpes virus that usually produces very mild symptoms in an infected person but has the ability to cause severe neurological damage in people with weakened immune systems especially in the newborn. Now, a phase III study conducted by Merck & Co.'s researchers regarding their prophylactic antiviral candidate letermovir has allegedly met its primary and secondary endpoints when it comes to preventing the development of significant cytomegalovirus (CMV) infection in patients receiving an allogeneic hematopoietic stem cell transplant (HSCT). As of the press time, the firm has confirmed that it plans to submit the regulatory applications for letermovir in EU and U.S. later this year.
Merck & Co.'s Letermovir
According to reports revealed by Genetic Engineering & Biotechnology News, letermovir therapy was started within the first 28 days following HSCT, wherein it has shown that out of the 495 patients who had undetectable CMV DNA at the start of the treatment. Consequently, 37.5 percent of patients in the letermovir arm developed clinically significant CMV infection through to week 14, as compared to the 60.6 percent of patients in the placebo arm. Thus, Letermovir has also been associated with lower all-cause mortality.
Furthermore, in one of his statements reported by Onc Live, Francisco M. Marty, MD, an attending physician in transplant and oncology infectious diseases at Dana-Farber Cancer Institute, who also happens to be the lead investigator has revealed that in the study they have conducted, letermovir was very effective at preventing cytomegalovirus infection when used early after transplant through day 100 post-transplant. Dr. Marty continues to explain that what's more compelling with their research is that there was lower morality in the letermovir group. Additionally, the study's lead author has also revealed that based on the study findings, letermovir as primary prophylaxis of CMV infection represents a potential new strategy for the prevention of CMV in this high-risk patient population.
Meanwhile, another expert, Eliav Barr, M.D., the senior vice president of Merck Research Laboratories said that patients who are undergoing auto-HSCT have an increased risk of HZ and associated complications due to impaired cellular immunity. On the other hand, just a couple of days ago, the Phase III letermovir results have also been reported just a couple of days after Merck announced positive data from its first Phase III study evaluating the inactivated varicella zoster virus vaccine (VZV) candidate V212.