The drug is an antiviral agent that was approved by the 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 (HSCT).
The FDA has also approved a separate supplemental new drug application (sNDA), from the company, known as MSD outside of the US and Canada, to extend prophylaxis with Prevymis to 200 days in certain HSCT recipients.
The FDA granted priority review for the sNDA for Prevymis for prophylaxis of CMV 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.
If the recipient is CMV seropositive and the donor is either seropositive or seronegative (CMV D+/R+ CMV D-/R+), it is considered a moderate risk for the development of CMV infection. If both recipient and donor are CMV seronegative (CMV D-/R-), it is considered low risk.
FDA priority review
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.
Dr. Nicholas Kartsonis, senior vice president, vaccines, and infectious diseases, at Merck, said: “Certain high-risk individuals who develop CMV infection following receipt of a kidney transplant are at increased risk for transplant failure and death. Prevymis has the potential to be an important new option with a favorable safety profile for patients at risk for CMV infection following a kidney transplant. We look forward to the FDA’s review of our filings.”
The sNDA for use of Prevymis for CMV prophylaxis in kidney transplant recipients is supported by a phase 3, randomized, double-blind clinical trial that demonstrated non-inferior efficacy and a more favorable safety profile for the drug 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.
Lower risk of leukopenia
In the study, Prevymis had fewer drug-related adverse events (AEs) 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 Merck’s drug than with valganciclovir.
The sNDA for 200 days of prophylaxis with Prevymis is supported by a phase 3, randomized, double-blind, placebo-controlled trial that evaluated the safety and efficacy of extending prophylaxis with Prevymis from 100 to 200 days, compared to placebo, in CMV-seropositive recipients [R+] at high risk for clinically significant CMV infection following an HSCT.
This trial met its primary endpoint and prophylaxis with the drug extended to 200 days was superior to placebo in reducing the rate of clinically significant CMV infection from week 14 through week 28 post-HSCT in allogeneic R+ HSCT recipients.