Evaluating Real-World Experience With Maribavir for Treatment of Refractory/Resistant Cytomegalovirus in Renal Transplant Recipients.

Introduction: Maribavir was recently approved by the FDA, expanding treatment options for post-solid-organ transplant refractory/resistant CMV. We sought to describe the post-marketing experience with maribavir at a large academic transplant center.

Methods: This was a retrospective observational study of all renal transplant recipients treated with maribavir for refractory/resistant CMV DNAemia/disease. CMV viral loads, immunosuppression regimens and management, resistance testing, and antiviral therapy durations were reviewed. Outcomes of interest included treatment success, defined as undetectable CMV DNAemia for two consecutive weeks or detected but unquantifiable DNAemia for five consecutive weeks, as well as the emergence of antiviral resistance, and recurrent DNAemia.

Results: From 2021 to 2023, 5/10 (50%) patients achieved durable virologic suppression with maribavir (classified as responders). Among responders, 2/5 (40%) experienced low-level CMV DNAemia recurrence (defined as a viral load less than 1000 IU/mL) within 8 weeks of antiviral discontinuation. Among nonresponders, 2/3 (66.7%) were found to have UL97 protein mutations associated with maribavir resistance identified 85 and 75 days after initiation of maribavir. Two patients are currently on maribavir with clinical outcomes that are yet to be determined. Responders had a mean reduction of 200 mg (SD-274 mg) in mycophenolate dosing with nonresponders having a mean increase of 167 mg (SD-764 mg).

Conclusions: Maribavir, often in conjunction with mycophenolate dose reduction, was effective for many patients with refractory/resistant CMV DNAemia at our transplant center, though several experienced recurrent DNAemia. In patients who did not respond to therapy, resistance to maribavir was frequently detected. Clinicians treating these patients should remain vigilant for rebound CMV DNAemia and consider repeat antiviral resistance testing.