CT053, a fully human B-cell maturation antigen-specific chimeric antigen receptor (CAR) T-cell therapy, was found to be safe and effective for patients living with relapsed and/or refractory multiple myeloma (RRMM), according to research presented at the 62nd American Society of Hematology Annual Meeting and Exposition. 

CT053 is comprised of autologous T cells genetically modified with a second-generation CAR incorporating a fully human B-cell maturation antigen (BCMA)-specific single-chain fragment variant (25C2) with high binding affinity.

The phase 1 study included 24 subjects with an 87.5 overall response rate (ORR) and a 79.2% complete response rate. The median duration of response was 21.8 months. The ongoing 1b/2 study included 20 participants with RRMM who had received 3 or more prior lines of therapy including a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 antibody. 

According to the study, 14 patients received CT053 infusion in the phase 1b study, of whom 86% experienced grade 1 or 3 CRS. The most common grade 3 or greater adverse effect was hematological toxicity. At the data cutoff point, 10 patients were evaluable for at least 2 months of efficacy assessment, with a median follow-up of 2.5 months. According to the study, an ORR of 100% was observed. Twelve patients were evaluable for bone marrow sample, of which 11 were MRD-negative at the 10-5 sensitivity level.

CT053 at a target dose of 1.5-3.0×108 CAR+ T cells causes an early and deep response, notably in MRD negativity. According to the study, CT053 has an acceptable safety profile. 

Kumar, S. 133 Results from Lummicar-2: A Phase 1b/2 Study of Fully Human B-Cell Maturation Antigen-Specific CAR T Cells (CT053) in Patients with Relapsed and/or Refractory Multiple Myeloma [Abstract] December 5, 2020. Accessed December 15, 2020. https://ash.confex.com/ash/2020/webprogram/Paper139802.html.