FDA Approval Announcement
Yesterday, the U.S. Food and Drug Administration (FDA) approved an extended duration of use for Prevymis (letermovir), from 100 days to 200 days post‑transplantation, for the prevention of late‑onset cytomegalovirus (CMV) infection and disease in adult CMV‑seropositive recipients undergoing allogeneic hematopoietic stem cell transplantation (HSCT).
Basis for Approval: Phase 3 Trial (NCT03930615)
The approval was based on data from a double‑blind, placebo‑controlled, Phase 3 study evaluating the efficacy of extending Prevymis prophylaxis from Week 14 (approximately 100 days) to Week 28 (approximately 200 days) post‑HSCT in patients at risk of late‑onset CMV infection and disease.
Study Design
Study participants who completed 100 days of Prevymis prophylaxis post‑HSCT were randomized to receive either:
Prevymis (n = 144)
Placebo (n = 74)
from Week 14 to Week 28 post‑HSCT.The primary endpoint was the percentage of patients with clinically significant CMV infection during this period.
Key Efficacy Results
Prevymis group:
Treatment failure rate: 2.8%
Clinically significant CMV infection (Week 14–28): 1.4%
Discontinuation due to CMV viremia by Week 28: 1.4%
Placebo group:
Treatment failure rate: 18.9%
Clinically significant CMV infection (Week 14–28): 17.6%
Discontinuation due to CMV viremia by Week 28: 1.4%
Stratified adjusted treatment difference: −16.1 (95% CI: −25.8, −6.5; P = 0.0005)
Cumulative Incidence of Clinically Significant CMV Infection
Prevymis group:
End of prophylaxis (Week 28): 1.6%
Week 38: 15.6%
Placebo group:
Week 28: 17.6%
Week 38: 19.0%
No additional cases of clinically significant CMV infection were reported in either group from Week 38 to Week 48.
Subgroup Analyses
Efficacy was consistent across subgroups defined by age, gender, race, and risk factors for late‑onset CMV infection and disease.
Additional Approved Indication
Prevymis is also indicated for the prevention of CMV disease in high‑risk adult kidney transplant recipients (donor CMV‑seropositive / recipient CMV‑seronegative [D+/R−]).
