Drug-drug interactions of ritonavir-boosted SARS-CoV-2 protease inhibitors in solid organ transplant recipients: experience from the initial use of lopinavir-ritonavir.

OBJECTIVES: To review the drug-drug interactions between tacrolimus and lopinavir/ritonavir in 23 patients who received solid organ transplant during the first wave of COVID-19 and to determine the efficacy as well as safety of prednisone monotherapy. METHODS: Observational study performed between March and June 2020 in solid organ transplant recipients admitted with an established diagnosis of SARS-CoV-2 infection who received lopinavir/ritonavir (≥2 doses). Once lopinavir/ritonavir therapy was initiated, calcineurin inhibitor treatment was temporarily switched to prednisone monotherapy (15-20 mg/d) to avoid drug-drug interactions and toxicity. After lopinavir/ritonavir treatment completion, immunosuppressive treatment was restarted with reduced doses of prednisone-tacrolimus (target minimum blood concentration -C0- approximately 5 ng/mL). Patients were observed for 3 months to confirm the absence of rejection. RESULTS: The median time from discontinuation of tacrolimus to initiation of lopinavir/ritonavir was 14 hours (interquartile range [IQR], 12-15) and from discontinuation of lopinavir/ritonavir to resumption of tacrolimus 58 hours (IQR, 47-81). The duration of lopinavir/ritonavir treatment was 7 days (IQR, 5-7). Nine of the 21 (42.8%) patients on tacrolimus treatment had C0 above the cutoff point after lopinavir/ritonavir initiation, despite having been substituted with prednisone before lopinavir/ritonavir initiation. Three patients had very high concentrations (>40 ng/mL) and developed toxicity. No episodes of acute rejection were diagnosed. DISCUSSION: We did not observe toxicity in patients for whom tacrolimus was discontinued 24 hours before starting lopinavir/ritonavir and reintroduced at half dose 48 to 72 hours after lopinavir/ritonavir discontinuation. Prednisone monotherapy during lopinavir/ritonavir therapy was safe with no episodes of acute rejection. Experience with lopinavir/ritonavir may be applicable to the use of nirmatrelvir/ritonavir, but larger multicentre studies are needed to confirm these findings.

COVID-19, rejection, and cutaneous mucormycosis in a long-term liver transplant recipient – the vicious cycle of immunosuppression and opportunistic infections

Opportunistic infections, including fungal infections, are dreaded complications of liver transplantation, particularly early after transplant. We describe the case of a patient that presented 6 years after liver transplant with a Lichtheimia corymbifera-infected leg ulcer, following previous COVID-19 infection and moderate rejection requiring steroid pulses. The patient required long-term antifungal therapy, repeated surgical debridement and eventually wound coverage with meshed split-thickness skin graft. Our case illustrates the challenges in the treatment of cutaneous mucormycosis and highlights the difficulties in achieving an accurate balance between the risk of opportunistic infections and rejection in this population.

A propensity score-matched analysis of mortality in solid organ transplant patients with COVID-19 compared to non-solid organ transplant patients.

In the context of COVID-19 pandemic, we aimed to analyze the epidemiology, clinical characteristics, risk factors for mortality and impact of COVID-19 on outcomes of solid organ transplant (SOT) recipients compared to a cohort of non transplant patients, evaluating if transplantation could be considered a risk factor for mortality. From March to May 2020, 261 hospitalized patients with COVID-19 pneumonia were evaluated, including 41 SOT recipients. Of these, thirty-two were kidney recipients, 4 liver, 3 heart and 2 combined kidney-liver transplants. Median time from transplantation to COVID-19 diagnosis was 6 years. Thirteen SOT recipients (32%) required Intensive Care Unit (ICU) admission and 5 patients died (12%). Using a propensity score match analysis, we found no significant differences between SOT recipients and non-transplant patients. Older age (OR 1.142; 95% [CI 1.08-1.197]) higher levels of C-reactive protein (OR 3.068; 95% [CI 1.22-7.71]) and levels of serum creatinine on admission (OR 3.048 95% [CI 1.22-7.57]) were associated with higher mortality. The clinical outcomes of SARS-CoV-2 infection in our cohort of SOT recipients appear to be similar to that observed in the non-transplant population. Older age, higher levels of C-reactive protein and serum creatinine were associated with higher mortality, whereas SOT was not associated with worse outcomes.