Safety, Efficacy, and Relapse of Nirmatrelvir-Ritonavir in Kidney Transplant Recipients Infected With SARS-CoV-2.

Introduction: The efficacy of nirmatrelvir-ritonavir (NR; Paxlovid, Pfizer, New York, NY) to decrease the risk of progression to severe COVID-19 in high-risk patients has been demonstrated. However, evidence in infected kidney transplant recipients (KTRs) is lacking. Moreover, NR has significant and potentially harmful interactions with calcineurin inhibitors (CNIs). Methods: In this single-center retrospective study, we included all KTRs treated with NR from April 28 to June 3, 2022. A standard management strategy of CNI dose adaptation (discontinuation of tacrolimus 12 hours before the start of NR and administration of 20% of the cyclosporine dose) and laboratory follow-up was applied. Results: A total of 14 patients were included. Compared with day-0 (day before NR initiation), day-7 plasma creatinine concentrations and SARS-CoV-2 viral loads were similar (P = 0.866) and decreased (P = 0.002), respectively. CNI trough concentrations at the end of the treatment were satisfactory, nonetheless, with high individual variability. After a median follow-up time of 34 days, no death or viral pneumonia were observed. Nevertheless, 2 patients experienced early SARS-CoV-2 infection relapses (at day-10 and day-21) associated with an increase in SARS-CoV-2 viral loads. Conclusion: NR can be used in KTRs but requires a strict protocol of drug adaptation. We observed 2 cases of early relapse after NR treatment that need further investigations.

Monoclonal Antibody Therapy in Kidney Transplant Recipients With Delta and Omicron Variants of SARS-CoV-2: A Single-Center Case Series.

Rationale & Objective: Neutralizing monoclonal antibody treatments have shown promising preliminary results in kidney transplant recipients infected with severe acute respiratory syndrome coronavirus 2. However, their efficacy in kidney transplant recipients infected with the Omicron variant has not been reported yet. Study Design: Single-center retrospective study. Setting & Participants: We included all consecutive kidney transplant recipients treated with monoclonal antibodies for severe acute respiratory syndrome coronavirus 2 infections (positive polymerase chain reaction on nasopharyngeal swab) between June 10, 2021, and January 14, 2022. Forty-seven kidney transplant recipients were included. All patients had symptoms evolving for ≤7 days and no oxygen therapy need at monoclonal antibody infusion. Results: Symptoms at diagnosis were mainly cough (n = 25; 53%) and fever (n = 15; 32%). Eighty-three percent of the cohort (n = 39) had been vaccinated with at least 2 doses before infection, of whom 30 (77%) had demonstrated a vaccine-induced humoral response. They were treated with either casirivimab-imdevimab (n = 16; 34%) or sotrovimab (n = 31; 66%) a median of 2 days (range, 0-6 days) after the onset of symptoms. Except for 1 mild allergic reaction during casirivimab-imdevimab infusion, no side effects were reported. The median viral loads at admission (day 0) and 7 days after monoclonal antibody infusion were 2,110,027 copies/mL (range, 1,000-153,798,962 copies/mL) and 1,000 copies/mL (range, 0-10,000,000 copies/mL), respectively. Genotypes were available for 22 kidney transplant recipients (47%). Omicron, Delta, and Gamma variants were identified in 13 (59%), 8 (36%), and 1 (5%) patients, respectively. In kidney transplant recipients infected with the Omicron variant, the median viral loads at day 0 and day 7 were 752,789 copies/mL (range, 4,000-12,859,300 copies/mL) and 1,353 copies/mL (range, 0-1,211,163 copies/mL), respectively. 2 kidney transplant recipients required hospitalization immediately after sotrovimab perfusion for oxygen therapy that was weaned in 3 days, allowing patients' discharge. None were admitted to the intensive care unit or died. Limitations: Small sample size, no control group. Conclusions: Neutralizing monoclonal antibody therapy is associated with positive outcomes in kidney transplant recipients with mild coronavirus disease 2019, including those infected with the Omicron variant.