21 February 2023 - - The US Food and Drug Administration has accepted for review two supplemental new drug applications for PREVYMIS (letermovir), US-based pharmaceutical company Merck (NYSE: MRK) said.

The FDA granted priority review for the sNDA for PREVYMIS for prophylaxis of cytomegalovirus disease in adult kidney transplant recipients at high risk (D+/R-); the Prescription Drug User Fee Act (PDUFA), or target action date, is June 5, 2023.

The FDA grants priority review to medicines and vaccines that, if approved, would provide a significant improvement in the safety or effectiveness of the treatment or prevention of a serious condition.

A second sNDA to extend use of PREVYMIS from 100 days to 200 days in adults receiving an allogeneic hematopoietic stem cell transplant who are at risk for late CMV infection and disease was also accepted for review, with a PDUFA date of Sept. 7, 2023.

PREVYMIS is a first-in-class antiviral agent that was approved by the US FDA in 2017 and is indicated for prophylaxis of CMV infection and disease in adult CMV-seropositive recipients [R+] of an allogeneic hematopoietic stem cell transplant.

Data supporting the sNDA for CMV prophylaxis in kidney transplant recipients
The sNDA for use of PREVYMIS for CMV prophylaxis in kidney transplant recipients is supported by a Phase 3, randomized, double-blind clinical trial (NCT03443869) that demonstrated non-inferior efficacy and a more favorable safety profile for PREVYMIS compared to valganciclovir, the current standard of care for CMV prophylaxis in kidney transplant recipients.

Data from the trial were presented during a late-breaking oral session at the IDWeek annual meeting in October 2022.

In the study, PREVYMIS had a more favorable safety profile compared to valganciclovir, with fewer drug-related adverse events and study drug discontinuations due to adverse events reported in the PREVYMIS group compared to the valganciclovir group.

The incidence of leukopenia (decrease in leukocytes, or white blood cells) and neutropenia (decrease in neutrophils, the most common type of white blood cell) was lower with PREVYMIS than with valganciclovir:

The treatment difference in leukopenia/neutropenia was 38% lower in the PREVYMIS group versus the valganciclovir group and was statistically significant (95% CI, -45.1, -30.3; p value =