Conversion to belatacept within 1‐year of renal transplantation in a diverse cohort including patients with donor‐specific antibodies

Desensitization and belatacept-based maintenance therapy in pregnancy-sensitized monkeys receiving a kidney transplant

Among sensitized patients awaiting a transplant, females are disproportionately represented, partly because of pregnancy-induced sensitization. Using female NHPs sensitized by pregnancy alone, we examined the efficacy of costimulation blockade and proteasome inhibition for desensitization. Three animals received no desensitization (control), and seven animals received weekly carfilzomib (27 mg/m2) and belatacept (20 mg/kg) before kidney transplantation. All animals received renal allografts from crossmatch-positive/maximally MHC-mismatched donors. Controls and three desensitized animals received tacrolimus-based immunosuppression. Four desensitized animals received additional belatacept with tacrolimus-based immunosuppression. Multiparous females had less circulating donor-specific antibody when compared to skin-sensitized males before transplantation. While females receiving desensitization showed only a marginal survival benefit over control females (MST = 11 days versus 63 days), additional belatacept to posttransplant maintenance significantly prolonged graft survival (MST > 164 days) and suppressed posttransplant DSA and circulating follicular helper T-like cells. This combination of therapies demonstrates great potential to reduce antibody-mediated rejection in sensitized recipients.

Time-Limited Therapy with Belatacept in Kidney Transplant Recipients

Introduction: In kidney transplant recipients, belatacept is usually pursued indefinitely after it has been started. In the setting of the belatacept shortage and after having evaluated the benefit–risk ratio, we established a strategy consisting of time-limited belatacept therapy/transient calcineurin inhibitor withdrawal, whose results are analyzed in that study. Methods: We considered all the kidney transplant recipients that had been switched from conventional immunosuppressive therapy to belatacept and then for whom belatacept has been withdrawn intentionally. Furthermore, in the first 8 patients, we assessed changes in peripheral blood mononuclear cells (PBMC) transcriptome using RNAseq before and 3 months after belatacept withdrawal. Results: Over the study period, 28 out of 94 patients had belatacept intentionally withdrawn including 25 (89%) switched to low-dose CNI. One rejection due to poor compliance occurred. The eGFR after 12 months remained stable from 48 ± 19 mL.1.73 m⁻² to 46 ± 17 mL.1.73 m⁻² (p = 0.68). However, patients that resumed belatacept/withdrew CNIs (n = 10) had a trend towards a better eGFR comparing with the others (n = 15): 54 ± 20 mL.1.73 m⁻² vs. eGFR 43 ± 16 mL.1.73 m⁻², respectively (p = 0.15). The only factor associated with belatacept resumption was when the withdrawal took place during the COVID-19 outbreak. Transcriptome analysis of PBMCs, did not support rebound in alloimmune response. Conclusions: These findings underpin the use of belatacept as part of a time-limited therapy, in selected kidney transplant recipients, possibly as an approach to allow efficient vaccination against SARS-CoV-2.

Conversion from Calcineurin Inhibitor- to Belatacept-Based Maintenance Immunosuppression in Renal Transplant Recipients: A Randomized Phase 3b Trial

BACKGROUND

Calcineurin inhibitors (CNIs) are standard of care after kidney transplantation, but they are associated with nephrotoxicity and reduced long-term graft survival. Belatacept, a selective T cell costimulation blocker, is approved for the prophylaxis of kidney transplant rejection. This phase 3 trial evaluated the efficacy and safety of conversion from CNI-based to belatacept-based maintenance immunosuppression in kidney transplant recipients.

METHODS

Stable adult kidney transplant recipients 6-60 months post-transplantation under CNI-based immunosuppression were randomized (1:1) to switch to belatacept or continue treatment with their established CNI. The primary end point was the percentage of patients surviving with a functioning graft at 24 months.

RESULTS

Overall, 446 renal transplant recipients were randomized to belatacept conversion ( n =223) or CNI continuation ( n =223). The 24-month rates of survival with graft function were 98% and 97% in the belatacept and CNI groups, respectively (adjusted difference, 0.8; 95.1% CI, -2.1 to 3.7). In the belatacept conversion versus CNI continuation groups, 8% versus 4% of patients experienced biopsy-proven acute rejection (BPAR), respectively, and 1% versus 7% developed de novo donor-specific antibodies (dnDSAs), respectively. The 24-month eGFR was higher with belatacept (55.5 versus 48.5 ml/min per 1.73 m 2 with CNI). Both groups had similar rates of serious adverse events, infections, and discontinuations, with no unexpected adverse events. One patient in the belatacept group had post-transplant lymphoproliferative disorder.

CONCLUSIONS

Switching stable renal transplant recipients from CNI-based to belatacept-based immunosuppression was associated with a similar rate of death or graft loss, improved renal function, and a numerically higher BPAR rate but a lower incidence of dnDSA.Clinical Trial registry name and registration number: A Study in Maintenance Kidney Transplant Recipients Following Conversion to Nulojix® (Belatacept)-Based, NCT01820572.

Belatacept Conversion Protocols and Outcomes in Kidney Transplant Recipients

BACKGROUND

Conversion from calcineurin inhibitor (CNI)-based to belatacept-based immunosuppression has become common; however, numerous protocols have emerged in lieu of a standardized protocol. The purpose of this study was to characterize belatacept conversion protocols from multiple centers and observe outcomes.

METHODS

This was a retrospective study that included Kaiser Permanente Southern California members. The primary outcome was rejection 6 months after conversion and secondary outcomes included change in serum creatinine and graft loss.

RESULTS

Seventy-eight patients were included. Thirteen distinct protocols were identified from 8 different transplant centers. Protocols varied by initial dose, induction schedule, and CNI taper. The observed rate of rejection was 6%. There was a trend toward an association of rejection with lower tacrolimus exposure at the time of conversion and lower mycophenolic acid dosing postconversion. Graft survival was 88% and patient survival was 94%. There was a significant improvement in creatinine after conversion. Those with early conversions and creatinine >2.0 mg/dL at the time of conversion had the best response.

CONCLUSIONS

A large variety of belatacept conversion protocols were identified. Protocols were defined by the initial dose, induction regimen, and CNI taper. Rejection rates were low and may be influenced by exposure to maintenance immunosuppression during and after conversion. Most patients showed stabilization and improvement in creatinine postconversion, with the largest effect in those with an early conversion and serum creatinine >2.0 mg/dL.

Prevention of acute rejection after rescue with Belatacept by association of low-dose Tacrolimus maintenance in medically complex kidney transplant recipients with early or late graft dysfunction

Background

Increased acute rejection risk in rescue protocols with Belatacept may limit its use particularly in medically complex patients where preexisting increased risk of rejection couples with CNI toxicity.

Methods

Retrospective analysis was performed in 19 KTs shifted to a Belatacept-based immunosuppression with low-dose Tacrolimus (2–3 ng/mL) after evidence of allograft disfunction, including patients with primary non-function (PNF), chronic-active antibody-mediated rejection (cAMR), history of previous KTs and/or other concomitant transplants (liver, pancreas). Evaluation of CD28⁺ CD4⁺ effector memory T cell (T_EM) before conversion was performed in 10/19.

Results

Kidney function significantly improved (median eGFR 16.5 ml/min/1.73m² before vs 25 ml/min after; p = 0.001) at a median time after conversion of 12.5 months (9.1–17.8). Overall graft and patient survival were 89.5% and 100% respectively. Definitive weaning from dialysis in 5/5 KTs with PNF was observed, whereas 7/8 patients lost their graft within first year in a control group. eGFR significantly ameliorated in re-trasplants (p = 0.001) and stabilized in KTs with other organ transplants or cAMR. No acute rejection episodes occurred, despite the significant risk suggested by high frequency of CD28⁺ CD4⁺ T_EM in most patients. Opportunistic infections were limited and most common in early vs late-converted.

Conclusions

Rescue association of Belatacept with low-dose Tacrolimus in medically complex KTs is a feasible option that allows prevention of acute rejection and amelioration of graft function.

Conversion to belatacept maintenance immunosuppression in HIV-positive kidney transplant recipients

There are only scattered case reports documenting belatacept use in HIV + kidney transplant recipients. We performed a retrospective review to describe short-term outcomes following conversion to belatacept in a cohort of HIV + patients. Patients were included if they were converted to belatacept between May 2015 and May 2019, had an HIV- donor, and received ≥4 doses of belatacept. All patients were treated with non-depleting induction and triple maintenance immunosuppression. Allograft and HIV-related outcomes were collected from the date of belatacept infusion until May 2020. Ten HIV + kidney transplant recipients were identified, who were converted to belatacept a median of 364 days post-transplant. At last follow-up (median 3.3 years), 8 patients remained on belatacept therapy, and all patients were alive with functioning allografts. Mean estimated glomerular filtration rates (eGFR) improved from 31.6 mL/min at baseline to 42.8 mL/min at 1 year (P = .03). Two patients developed acute rejection, with one necessitating conversion back to tacrolimus. All patients maintained undetectable HIV-1 viral loads at last follow-up. One patient each developed pneumocystis pneumonia and Kaposi sarcoma following conversion, which were responsive to standard medical therapy. In our cohort of stable HIV + kidney transplant recipients, conversion to belatacept was associated with excellent early patient and allograft survival and improved eGFR at 1 year.