Maribavir treatment for resistant cytomegalovirus disseminated disease in kidney transplant recipients: A case-based scoping review of real life data in literature

The treatment of refractory CMV is often associated with high toxicity. Maribavir (MBV) is a novel oral antiviral, known for its favourable safety profile in fragile patients. We describe a case of CMV disease with end organ damage following kidney transplantation at high risk, for recipient-donor serological mismatch. A 54-year-old female with history of obesity, hypertension, and chronic kidney disease, on prednisone and tacrolimus after kidney transplantation in November 2022, soon after developed primary CMV infection, treated with Valganciclovir and CMV Ig. In January 2023 the patient presented with fever and dyspnea. Pulmonary miliary opacities and right-upper lobe consolidation were found at CT-scan along with CMV-DNA positivity on BAL and serum. Lung biopsy confirmed CMV infection. Antiviral was switched to Ganciclovir. Despite initial benefit, fever and respiratory failure happened 8 days later, leading to intubation at day 15. Due to slow decrease serum CMV-DNA and detection of UL97 mutation, conferring resistance to valganciclovir and ganciclovir, the patient was started on foscarnet and letermovir. She was extubated after a gradual respiratory improvement and discharged from ICU to rehabilitation department with HFNC; reduction in serum CMV-DNA, but persistently elevated CMV-DNA on BAL were documented. At week 8, MBV was started and letermovir continued, for a 8 weeks course, without notable adverse effects. Respiratory function improved but soon after septic shock occurred. A bone marrow biopsy resulted in lymphoma, without indications for treatment: the patient developed coma and died 6 months after admission. MBV has recently been approved in Europe for treatment of R/R CMV in HSCT and SOT recipients. MBV showed superior rates of viraemia clearance after 8 weeks compared to SOC, demonstrating also a favourable safety profile with fewer patients discontinuing treatment and being affected by nephrotoxicity and neutropenia. Its main side effects are taste impairment, gastro-intestinal symptoms and asthenia. Based on actual promising perspectives regarding antiviral stewardship, more data are required to corroborate benefit of MBV in terms of toxicity and impact on mortality in highly fragile populations as SOT recipients. MBV received approval for the treatment of refractory or resistant CMV infections to other antiviral agents. Nevertheless, real-life data on efficacy and safety of MBV are still lacking. We conducted a narrative review of the current literature on MBV as treatment for CMV infection in kidney transplant recipients to understand clinical characteristics, safety and outcomes of MBV in this population. A search was run on the main scientific databases. 194 papers were identified, of which 188 were excluded by title and abstract evaluation. Subsequently, 6 papers were included. We performed descriptive statistics on the entire study population. The studies included in our analysis showed a higher prevalence of male subjects. The median age was 57 year. CKD was the most frequently reported comorbidity. Seven patients reported a donor/recipient mismatch (D+/R-). The case report and the cohort of patients collected from the literature show that MBV was used as an option in R/R CMV, notably for the presence or suspicion of CMV resistance to previous treatment. The clinical presentation of CMV in kidney SOT was heterogenous and varied from isolated reactivation of CMV-DNAemia, isolated fever or gastrointestinal involvement. For mild to moderate CMV disease, as with the cases reported in our review, or for proven ganciclovir, foscarnet or cidofovir resistance, MBV could be a valuable option. Outcomes of the patients treated with MBV were not reported in all the studies; however, where reported, 45.4% of the cases developed virological failure during MBV treatment with the development of specific resistance to MBV. MBV was generally well-tolerated, with low rates of toxicity, normally reversible. The introduction of new oral antivirals, such as MBV, could improve treatment, prophylaxis and preemptive treatment strategies, especially in anti-CMV treatment experienced patients.