Summary of Maribavir (SHP620) Drug–Drug Interactions Based on Accumulated Clinical and Nonclinical Data

Abstract

Introduction Maribavir, a potent and orally bioavailable antiviral, is being evaluated in Phase 3 trials for the treatment of cytomegalovirus (CMV) infections in transplant patients. Often numerous concomitant medications are administered to these patients to manage their comorbidities. A thorough evaluation of maribavir potential for drug–drug interactions (DDIs) is warranted and required for the regulatory approval. Objectives To thoroughly evaluate potential DDIs for maribavir. Methods Extensive in vitro studies were conducted to evaluate the potential involvement of cytochrome P450s (CYPs), uridine diphosphate glucuronosyltransferases (UGTs) and transporters on the disposition of maribavir, as well as the inhibitory and induction effect of maribavir on these enzymes and transporters. Clinical Phase 1 studies included a human mass-balance study, two probe-cocktail studies, and five DDI studies with ketoconazole, rifampin, antacid, voriconazole, and tacrolimus. Results Maribavir is metabolized primarily in the liver through CYP3A4 (70–85%) and CYP1A2 (15–30%). Renal clearance is a minor route ( Conclusions Maribavir has low risk for DDI. Inhibitors of CYP3A4 and/or P-gp may increase maribavir exposure, but dose adjustment of maribavir is not necessary. Potent inducers of CYP3A4 and P-gp decrease maribavir exposure, necessitating maribavir dose increase. Maribavir may increase exposure of immunosuppressants, such as tacrolimus. Therefore, monitoring of concomitant immunosuppressants' blood concentration should be considered at initiation, co-administration, and discontinuation of maribavir. Maribavir is not expected to interact with other concurrent medications.