Nirmatrelvir/Ritonavir Versus Remdesivir Therapy for Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Kidney Transplant Recipients: A Retrospective Study

Background: The prognosis of coronavirus disease-2019 (COVID-19) in solid organ transplant recipients is extremely poor. The efficacy and safety of various treatments used in COVID-19 have not been fully explored in kidney transplant recipients (KTRs). This study aims to investigate the safety and efficacy of nirmatrelvir/ritonavir versus remdesivir in adult KTRs infected with COVID-19. Methods: This single-center, retrospective, comparative study, conducted at a tertiary care hospital, enrolled adult KTRs with polymerase chain reaction-confirmed COVID-19 infection receiving nirmatrelvir/ritonavir or remdesivir from April 2021 to October 2023. The primary endpoint was the percentage of participants with COVID-19-related hospitalization within 28 days post-treatment completion. Secondary endpoints included graft rejection, patient and graft survival, worsening COVID-19 stage, and drug–drug interactions. Results: The nirmatrelvir/ritonavir and remdesivir groups consisted of 32 and 115 participants, respectively. The primary endpoint demonstrated no statistically significant differences between the groups. More patients in the remdesivir group progressed to a worse COVID-19 stage (0% vs. 12.7%, p < 0.05). The nirmatrelvir/ritonavir group experienced statistically more significant drug–drug interactions compared to the remdesivir group (90% vs. 0%, p < 0.05), mainly with calcineurin inhibitors. Conclusions: No statistically significant difference was found between nirmatrelvir/ritonavir and remdesivir in reducing COVID-19-related hospitalization among adult kidney transplant recipients.