Efficacy and safety of maribavir in Japanese patients with post-transplant cytomegalovirus infections: a phase III study

The efficacy and safety of maribavir, an oral benzimidazole nucleoside that inhibits viral kinase UL97, were evaluated in hematopoietic stem cell transplant (HSCT) or solid organ transplant (SOT) recipients with cytomegalovirus (CMV) infection. This phase III, multicenter, open-label, single-arm, interventional study (ClinicalTrials.gov: NCT05137717; Japan Registry of Clinical Trials: jRCT2021210056) investigated oral maribavir 400 mg twice daily for 8 weeks. Japanese HSCT/SOT recipients aged ≥ 16 years with symptomatic or asymptomatic CMV infection (including those resistant/refractory to ganciclovir, valganciclovir, or foscarnet) and without central nervous system CMV tissue-invasive disease or CMV retinitis were enrolled. Primary endpoints were confirmed CMV viremia clearance at week 8 for efficacy and treatment-emergent adverse events (TEAEs) for safety. Among 61 patients enrolled across 22 sites, 41 patients (median age 56.0 years; 36/41 [87.8%] were HSCT recipients) received ≥ 1 maribavir dose. At week 8, twenty-eight patients (28/41, 68.3%) achieved confirmed CMV viremia clearance. Overall, 36 patients (36/41, 87.8%) had ≥ 1 TEAE, including nausea (10/41, 24.2%), anemia (7/41, 17.1%), pyrexia (6/41, 14.6%), and headache (6/41, 14.6%). Two deaths were deemed unrelated to maribavir. In conclusion, maribavir was effective in achieving CMV viremia clearance, with an acceptable safety profile and tolerability, in Japanese HSCT or SOT recipients with CMV infection.