The Food and Drug Administration (FDA) has approved the extended use of Prevymis® (letermovir) from 100 to 200 days post-transplant for the prophylaxis of cytomegalovirus (CMV) infection and disease in adult CMV-seropositive recipients of an allogeneic hematopoietic stem cell transplant (HSCT) who are at risk for late CMV infection and disease.
The approval was based on data from a double-blind, placebo-controlled phase 3 study (ClinicalTrials.gov Identifier: NCT03930615) that assessed the efficacy of extending Prevymis prophylaxis from week 14 (approx. 100 days) through week 28 (approx. 200 days) post-HSCT in patients at risk for late CMV infection and disease.
Study participants who had completed Prevymis prophylaxis through ~100 days post-HSCT were randomly assigned to receive Prevymis (n=144) or placebo (n=74) from week 14 to week 28 post-HSCT. The primary endpoint was the percentage of patients with clinically significant CMV infections during that time period.
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Failure was reported in 2.8% of the Prevymis arm, with 1.4% of patients having clinically significant CMV infection from week 14 to week 28 and 1.4% having discontinued the study with CMV viremia before week 28. In the placebo arm, failure was reported in 18.9% of the group, with 17.6% of patients having clinically significant CMV infection from week 14 to week 28 and 1.4% having discontinued the study with CMV viremia before week 28. The stratum-adjusted treatment difference was -16.1 (95% CI, -25.8, -6.5; P =.0005).
In the Prevymis group, the cumulative rate of clinically significant CMV infection increased from 1.6% at the end of prophylaxis (week 28) to 15.6% at week 38. In the placebo group, the cumulative rate of clinically significant CMV infection increased from 17.6% at week 28 to 19.0% at week 38. No additional cases of clinically significant CMV infection were reported in either group between weeks 38 and 48.
Efficacy was found to be consistent across subgroups based on age, gender, race, and risk factors for late CMV infection and disease.
Prevymis is supplied as 240mg and 480mg tablets and in single-dose vials of 240mg/12mL and 480mg/12mL. In the clinical trial, Prevymis was administered either orally or intravenously; the dose was the same regardless of route of administration.
Prevymis is also indicated for prophylaxis of CMV disease in adult kidney transplant recipients at high risk (donor CMV seropositive/recipient CMV seronegative [D+/R-]).
This article originally appeared on MPR
