*Purpose: Biosimilars are FDA-approved alternatives to cost-prohibitive biologics, with no clinically meaningful differences in safety, purity, and potency. Rituximab-abbs, a biosimilar to rituximab, has labeled indications for several oncologic and autoimmune conditions. There is currently no published literature on the use of rituximab-abbs in the renal transplant population. In this report, we describe the safety and efficacy in renal transplants who received rituximab-abbs at our center.

*Methods: This is a retrospective chart review of renal transplants who received rituximab-abbs between June to December 2020. Indications, safety, and clinical outcomes were reviewed. Per institutional standard of care, renal transplants with donor-specific antibodies (DSA) greater than 2000 MFI at time of transplant receive rituximab-abbs 375 mg/m² intravenously once as part of induction therapy. For antibody medicated rejection (AMR), one dose is given at the end of the treatment course with plasmapheresis, bortezomib, corticosteroids, and enhanced maintenance immunosuppression.

*Results: Five patients received rituximab-abbs between the time period: 1 for baseline DSA, 4 for AMR. Patient characteristics and clinical outcomes are summarized in Table 1. All patients received appropriate pre-medications. No infusion-mediated reactions were reported. At a median follow-up of 72 days, no incidence of leukopenia (WBC < 3x10⁹/L), documented infections, and other serious adverse effects were reported. All patients achieved peak DSA MFI reduction and/or resolution at time of last follow-up. In contrast to rituximab, utilization of rituximab-abbs in these 5 patients resulted in a $13,275.78 cost-saving.

*Conclusions: Rituximab-abbs is a safe, well-tolerated, and cost-effective alternative to rituximab for the treatment of DSA in renal transplant patients. Further studies are necessary to determine efficacy of rituximab-abbs in DSA reduction in renal transplants.

« Back to 2021 American Transplant Congress