Maribavir for the Management of Cytomegalovirus in Adult Transplant Recipients: A Review of the Literature and Practical Considerations

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.

Bring it on again: antimicrobial stewardship in transplant infectious diseases: updates and new challenges

Advancement in solid organ transplantation and hematopoietic stem cell transplant continues to improve the health outcomes of patients and widens the number of eligible patients who can benefit from the medical progress. Preserving the effectiveness of antimicrobials remains crucial, as otherwise transplant surgeries would be unsafe due to surgical site infections, and the risk of sepsis with neutropenia would preclude stem cell transplant. In this review, we provide updates on three previously discussed stewardship challenges: febrile neutropenia, Clostridioides difficile infection, and asymptomatic bacteriuria. We also offer insight into four new stewardship challenges: the applicability of the "shorter is better" paradigm shift to antimicrobial duration; antibiotic allergy delabeling and desensitization; colonization with multidrug-resistant gram-negative organisms; and management of cytomegalovirus infections. Specifically, data are accumulating for "shorter is better" and antibiotic allergy delabeling in transplant patients, following successes in the general population. Unique to transplant patients are the impact of multidrug-resistant organism colonization on clinical decision-making of antibiotic prophylaxis in transplant procedure and the need for antiviral stewardship in cytomegalovirus. We highlighted the expansion of antimicrobial stewardship interventions as potential solutions for these challenges, as well as gaps in knowledge and opportunities for further research.