Maribavir for refractory cytomegalovirus infection (with or without resistance) in solid organ transplant recipients: subgroup analysis of the phase 3 randomized SOLSTICE study.

Background: In the phase 3 SOLSTICE study (NCT02931539), maribavir was superior to investigator-assigned therapy (IAT) for confirmed cytomegalovirus viremia clearance at study week 8 in hematopoietic cell/solid organ transplant (HCT/SOT) recipients. We report additional efficacy and safety analyses from the SOT subgroup.

Methods: Eligible solid organ transplant recipients (n=211) received maribavir 400 mg twice daily (n=142) or IAT (n=69) for 8 weeks (12 weeks' follow-up). Cytomegalovirus viremia clearance at week 8 (primary endpoint) and cytomegalovirus viremia clearance plus symptom control at the end of week 8 maintained through week 16 (key secondary endpoint) were assessed. Graft outcomes and treatment-emergent adverse events were analyzed.

Results: A higher proportion maribavir-treated patients achieved the primary endpoint than with IAT across transplant organ types, including kidney (maribavir: 59.5%, IAT: 34.4%), lung (47.5%, 13.6%), and heart (42.9%, 11.1%). Similar proportions of patients achieved the key secondary endpoint in both arms (13.4% versus 11.6%; adjusted difference: 2.4%; 95% CI: -7.05, 11.83%; p=0.620). Rates of treatment-emergent adverse events were: maribavir (96.5%), IAT (88.4%). Maribavir (3.5%) had fewer treatment discontinuations due to treatment-emergent adverse events than IAT (23.2%). There were no graft losses; patients in both arms experienced acute rejection (maribavir: 9 [6.3%]; IAT: 4 [5.8%]). Treatment-emergent maribavir mutations occurred in 28.2% of patients; 19/33 patients achieved viremia clearance with subsequent alternative treatment.

Conclusions: Consistent with findings in the overall SOLSTICE population, this subgroup analysis of SOT recipients demonstrated greater effectiveness of maribavir for cytomegalovirus viremia clearance and fewer discontinuations due to treatment-emergent adverse events than IAT.

Clinical Trial Registration Number: ClinicalTrials.gov; NCT02931539 DATA AVAILABILITY STATEMENT: The datasets, including the redacted study protocol, redacted statistical analysis plan, and individual participants data supporting the results reported in this article, will be made available within three months from initial request, to researchers who provide a methodologically sound proposal. The data will be provided after its deidentification, in compliance with applicable privacy laws, data protection and requirements for consent and anonymization.