Neutralization against Omicron variant in transplant recipients after three doses of mRNA vaccine.

The SARS-CoV-2 virus Omicron variant has now supplanted wild-type virus as the dominant circulating strain globally. Three doses of mRNA COVID-19 vaccine are recommended for transplant recipients as their primary vaccine series. However, the immunogenicity of mRNA vaccines as they specifically relate to the Omicron variant are not well studied. We analyzed Omicron-specific neutralization in transplant recipients after three-doses of mRNA-1273 vaccine. Neutralization was determined using a SARS-CoV-2 spike pseudotyped lentivirus assay with constructs for Omicron and Delta variants. A total of 60 transplant patients (kidney, kidney-pancreas, lung, heart, liver) were analyzed 1 month and 3 months after completion of three doses of mRNA-1273. At 1 month, 11/60 (18.3%) patients had detectable neutralizing antibody responses to Omicron (log10 ID50 of 2.38 [range 1.34-3.57]). At 3 months, 8/51 (15.7%) were positive (median log10 ID50 [1.68; range 1.12-3.61; approximate fivefold reduction over time]). The proportion of positive patients was lower for Omicron versus wild-type, and Omicron vs. Delta (p < .001). No demographic variables were found to be significantly associated with Omicron response. Many patients with a positive anti-RBD response still had undetectable Omicron-specific neutralizing antibody. In conclusion, three doses of mRNA vaccine results in poor neutralizing responses against the Omicron variant in transplant patients.

Organ transplantation using COVID-19-positive deceased donors.

The COVID-19 pandemic has influenced organ transplantation decision making. Opinions regarding the utilization of coronavirus disease-2019 (COVID-19) donors are mixed. We hypothesize that COVID-19 infection of deceased solid organ transplant donors does not affect recipient survival. All deceased solid organ transplant donors with COVID-19 testing results from March 15, 2020 to September 30, 2021 were identified in the OPTN database. Donors were matched to recipients and stratified by the COVID-19 test result. Outcomes were assessed between groups. COVID-19 test results were available for 17 694 donors; 150 were positive. A total of 269 organs were transplanted from these donors, including 187 kidneys, 57 livers, 18 hearts, 5 kidney-pancreases, and 2 lungs. The median time from COVID-19 testing to organ recovery was 4 days for positive and 3 days for negative donors. Of these, there were 8 graft failures (3.0%) and 5 deaths (1.9%). Survival of patients receiving grafts from COVID-19-positive donors is equivalent to those receiving grafts from COVID-19-negative donors (30-day patient survival = 99.2% COVID-19 positive; 98.6% COVID-19 negative). Solid organ transplantation using deceased donors with positive COVID-19 results does not negatively affect early patient survival, though little information regarding donor COVID-19 organ involvement is known. While transplantation is feasible, more information regarding COVID-19-positive donor selection is needed.

Comparative outcomes for over 100 deceased donor kidney transplants from SARS-CoV-2 positive donors: A single-center experience.

Emerging data support the safety of transplantation of extra-pulmonary organs from donors with SARS-CoV-2-detection. Our center offered kidney transplantation (KT) from deceased donors (DD) with SARS-CoV-2 with and without COVID-19 as a cause of death (CoV + COD and CoV+) to consenting candidates. No pre-emptive antiviral therapies were given. We retrospectively compared outcomes to contemporaneous DDKTs with negative SARS-CoV-2 testing (CoVneg). From February 1, 2021 to January 31, 2022, there were 220 adult KTs, including 115 (52%) from 35 CoV+ and 33 CoV + COD donors. Compared to CoVneg and CoV+, CoV + COD were more often DCD (100% vs. 40% and 46%, p < .01) with longer cold ischemia times (25.2 h vs. 22.9 h and 22.2 h, p = .02). At median follow-up of 5.7 months, recipients of CoV+, CoV + COD and CoVneg kidneys had similar rates of delayed graft function (10.3%, 21.8% and 21.9%, p = .16), rejection (5.1%, 0% and 8.5%, p = .07), graft failure (1.7%, 0% and 0%, p = .35), mortality (0.9%, 0% and 3.7%; p = .29), and COVID-19 diagnoses (13.6%, 7.1%, and 15.2%, p = .33). Though follow-up was shorter, CoV + COD was associated with lower but acceptable eGFR on multivariable analysis. KT from DDs at various stages of SARS-CoV-2 infection appears safe and successful. Extended follow-up is required to assess the impact of CoV + COD donors on longer term graft function.

mTOR inhibitors, mycophenolates, and other immunosuppression regimens on antibody response to SARS-CoV-2 mRNA vaccines in solid organ transplant recipients.

A recent study concluded that SARS-CoV-2 mRNA vaccine responses were improved among transplant patients taking mTOR inhibitors (mTORi). This could have profound implications for vaccine strategies in transplant patients; however, limitations in the study design raise concerns about the conclusions. To address this issue more robustly, in a large cohort with appropriate adjustment for confounders, we conducted various regression- and machine learning-based analyses to compare antibody responses by immunosuppressive agents in a national cohort (n = 1037). MMF was associated with significantly lower odds of positive antibody response (aOR = 0.09 0.130.18 ). Consistent with the recent mTORi study, the odds tended to be higher with mTORi (aOR = 1.00 1.452.13 ); however, importantly, this seemingly protective tendency disappeared (aOR = 0.47 0.731.12 ) after adjusting for MMF. We repeated this comparison by combinations of immunosuppression agents. Compared to MMF + tacrolimus, MMF-free regimens were associated with higher odds of positive antibody response (aOR = 2.39 4.267.92 for mTORi+tacrolimus; 2.34 5.5415.32 for mTORi-only; and 6.78 10.2515.93 for tacrolimus-only), whereas MMF-including regimens were not, regardless of mTORi use (aOR = 0.81 1.542.98 for MMF + mTORi; and 0.81 1.512.87 for MMF-only). We repeated these analyses in an independent cohort (n = 512) and found similar results. Our study demonstrates that the recently reported findings were confounded by MMF, and that mTORi is not independently associated with improved vaccine responses.

Utilization and outcomes of deceased donor SARS-CoV-2-positive organs for solid organ transplantation in the United States.

Coronavirus disease-19 has had a marked impact on the transplant population and processes of care for transplant centers and organ allocation. Several single-center studies have reported successful utilization of deceased donors with positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) tests. Our aims were to characterize testing, organ utilization, and transplant outcomes with donor SARS-CoV-2 status in the United States. We used Scientific Registry of Transplant Recipients data from March 12, 2020 to August 31, 2021 including a custom file with SARS-CoV-2 testing data. There were 35 347 donor specimen SARS-CoV-2 tests, 77.5% upper respiratory samples, 94.6% polymerase chain reaction tests, and 1.2% SARS-CoV-2-positive tests. Donor age, gender, history of hypertension, and diabetes were similar by SARS-CoV-2 status, while positive SARS-CoV-2 donors were more likely African-American, Hispanic, and donors after cardiac death (p-values <.01). Recipient demographic characteristics were similar by donor SARS CoV-2 status. Adjusted donor kidney discard (odds ratio = 2.08, 95% confidence interval [CI] 1.66-2.61) was higher for SARS-CoV-2-positive donors while donor liver (odds ratio = 0.44, 95% CI 0.33-0.60) and heart recovery (odds ratio = 0.44, 95% CI 0.31-0.63) were significantly reduced. Overall post-transplant graft survival for kidney, liver, and heart recipients was comparable by donor SARS-CoV-2 status. Cumulatively, there has been significantly lower utilization of SARS-CoV-2 donors with no evidence of reduced recipient graft survival with variations in practice over time.

Breakthrough COVID-19 cases despite prophylaxis with 150 mg of tixagevimab and 150 mg of cilgavimab in kidney transplant recipients.

The cilgavimab-tixagevimab combination retains a partial in vitro neutralizing activity against the current SARS-CoV-2 variants of concern (omicron BA.1, BA.1.1, and BA.2). Here, we examined whether preexposure prophylaxis with cilgavimab-tixagevimab can effectively protect kidney transplant recipients (KTRs) against the omicron variant. Of the 416 KTRs who received intramuscular prophylactic injections of 150 mg tixagevimab and 150 mg cilgavimab, 39 (9.4%) developed COVID-19. With the exception of one case, all patients were symptomatic. Hospitalization and admission to an intensive care unit were required for 14 (35.9%) and three patients (7.7%), respectively. Two KTRs died of COVID-19-related acute respiratory distress syndrome. SARS-CoV-2 sequencing was carried out in 15 cases (BA.1, n = 5; BA.1.1, n = 9; BA.2, n = 1). Viral neutralizing activity of the serum against the BA.1 variant was negative in the 12 tested patients, suggesting that this prophylactic strategy does not provide sufficient protection against this variant of concern. In summary, preexposure prophylaxis with cilgavimab-tixagevimab at the dose of 150 mg of each antibody does not adequately protect KTRs against omicron. Further clarification of the optimal dosing can assist in our understanding of how best to harness its protective potential.

Early clinical experience with nirmatrelvir/ritonavir for the treatment of COVID-19 in solid organ transplant recipients.

Nirmatrelvir/ritonavir (NR) use has not yet been described in solid organ transplant recipients (SOTRs) with mild COVID-19. The objective was to evaluate outcomes among SOTR and describe the drug-drug interaction of NR. This is an IRB-approved, retrospective study of all adult SOTR on a calcineurin inhibitor (CNI) or mammalian target of rapamycin inhibitor who were prescribed NR between December 28, 2021 and January 6, 2022. A total of 25 adult SOTR were included (n = 21 tacrolimus, n = 4 cyclosporine, n = 3 everolimus, n = 1 sirolimus). All patients were instructed to follow the following standardized protocol during treatment with 5 days of NR: hold tacrolimus or mTOR inhibitor or reduce cyclosporine dose to 20% of baseline daily dose. Four patients (16%) were hospitalized by day 30; one for infectious diarrhea and three for symptoms related to COVID-19. No patients died within 30 days of receipt of NR. Median tacrolimus level pre- and post-NR were 7.4 ng/ml (IQR, 6.6-8.6) and 5.2 (IQR, 3.6-8.7), respectively. Four patients experienced a supratherapeutic tacrolimus concentration after restarting tacrolimus post-NR. Our results show the clinically significant interaction between NR and immunosuppressive agents can be reasonably managed with a standardized dosing protocol. Prescribers should carefully re-introduce CNI after the NR course is complete.

ALVR109, an off-the-shelf partially HLA matched SARS-CoV-2-specific T cell therapy, to treat refractory severe COVID-19 pneumonia in a heart transplant patient: Case report.

An unvaccinated adult male heart transplant recipient patient with recalcitrant COVID-19 due to SARS-CoV-2 delta variant with rising nasopharyngeal quantitative viral load was successfully treated with ALVR109, an off-the-shelf SARS-CoV-2-specific T cell therapy. Background immunosuppression included 0.1 mg/kg prednisone, tacrolimus, and mycophenolate mofetil 1 gm twice daily for historical antibody-mediated rejection. Prior therapies included remdesivir, corticosteroids, and tocilizumab, with requirement for high-flow nasal oxygen. Lack of clinical improvement and acutely rising nasopharyngeal viral RNA more than 3 weeks into illness prompted the request of ALVR109 through an emergency IND. The day following the first ALVR109 infusion, the patient's nasopharyngeal SARS-CoV-2 RNA declined from 7.43 to 5.02 log10 RNA copies/ml. On post-infusion day 4, the patient transitioned to low-flow oxygen. Two subsequent infusions of ALVR109 were administered 10 and 26 days after the first; nasopharyngeal SARS-CoV-2 RNA became undetectable on Day 11, and he was discharged the following day on low-flow oxygen 5 weeks after the initial diagnosis of COVID-19. The clinical and virologic improvements observed in this patient following administration of ALVR109 suggest a potential benefit that warrants further exploration in clinical trials.