Safety and clinical efficacy of Relmacabtagene autoleucel (relma-cel) for systemic lupus erythematosus: a phase 1 open-label clinical trial

Abstract

Background: Systemic lupus erythematosus (SLE) is a classic systemic autoimmune disease mediated by autoantibodies. Chimeric antigen receptor T (CAR-T) cell therapy, known for its success in cancer, has shown promise in achieving durable B cell depletion and long-term remission in SLE. Relmacabtagene autoleucel (relma-cel) is the second anti-CD19 CAR-T product approved for marketing by the National Medical Products Administration (NMPA) in China and demonstrates its long-term efficacy in relapsed/refractory (r/r) large B cell lymphoma (LBCL). We report the results from a phase I open-label clinical trial of relma-cel in treating patients with moderately to severely active SLE. Methods: anti-CD19 CAR-T cells. All patients received lymphodepletion chemotherapy with fludarabine and cyclophosphamide. The primary endpoints were the incidence of dose-limiting toxicities (DLTs) and adverse events (AEs). Secondary endpoints included the evaluation of standard cellular pharmacokinetic parameters, the SLE Responder Index (SRI) response rate, and changes from baseline in the Safety of Estrogens in Lupus Erythematosus National Assessment-Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI), British Isles Lupus Assessment Group 2004 (BILAG-2004) and Physician's Global Assessment (PGA) scores post-treatment. This trial is registered with ClinicalTrials.gov, NCT05765006. Findings: was 18.74 CD3+CAR+ cells/μL (range: 7.94-228.36) by flow cytometry and 81766.5 copies/μg DNA (range: 50,979-1,140,893) by quantitative real-time PCR (qPCR). In all patients treated with relma-cel, CD19+ B cells in peripheral blood were almost completely depleted within 11-15 days and gradually recovered within 2-6 months. All patients achieved SRI response. Four patients achieved Definition of Remission in SLE (DORIS) remission criteria and seven patients reached the Lupus Low Disease Activity State (LLDAS) criteria within 1-4 months following relma-cel infusion. Interpretation: This study preliminarily demonstrated that relma-cel is an effective and safe CAR-T product for the treatment of patients with moderately to severely active SLE, providing valuable clinical insights into the management of rare complications. Further studies with larger sample sizes are warranted. Funding: National Natural Science Foundation of China.

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