Anitocabtagene autoleucel (anito-cel) clinical trial manufacturing experience in patients with relapsed/refractory (RR) or newly diagnosed (ND) multiple myeloma (MM).

2550 Background: Anito-cel is an autologous D-Domain–based anti-BCMA chimeric antigen receptor (CAR) T-cell therapy that demonstrated deep and durable efficacy and manageable safety in a Phase 1 study and a Phase 2 registrational study (iMMagine-1) in 4L+ RRMM (Bishop et al. ASH 2024; Patel et al. ASH 2025). The D-Domain has a fast off-rate and facilitates high transduction efficiency, high CAR expression, decreased risk of tonic signaling, and potential for enhanced manufacturing efficiency and optimal tumor cytotoxicity. Anito-cel is also being investigated in patients with RRMM with 1-3 prior therapies and in patients with NDMM. The anito-cel CAR T-cell therapy manufacturing process has been optimized by leveraging the learnings from the robust development process of another CAR T-cell therapy, axicabtagene ciloleucel (axi-cel). Axi-cel is an autologous anti-CD19 CAR T-cell therapy approved in 2L large B-cell lymphoma based on the ZUMA-7 trial, with a demonstrated high manufacturing success rate (MSR) in both clinical trial and commercial real-world settings (100% and 99%, respectively; Alquist et al. TCT 2024). Here we report initial anito-cel manufacturing experience from 2 MM clinical trials. Methods: Pooled manufacturing outcomes from adults with MM enrolled and leukapheresed in iMMagine-3 or GEM-AnitoFIRST from 09/2024 to 10/2025 were included. First pass (FP)-MSR was defined as anito-cel lots manufactured on first attempt and within specification per total first attempt lots dispositioned plus lots not dispositioned due to termination in the period (excluding those terminated for patient withdrawal). The median turnaround time (mTAT) was defined as the time from leukapheresis to the quality release of final anito-cel product. Results: There was a total of 104 patients who were leukapheresed and whose lots were dispositioned as of October 31, 2025; anito-cel was successfully manufactured for 100% of these patients. The FP-MSR was 99.0% with 1/102 lots rejected on disposition (Table). The global mTAT was 18 days (interquartile range IQR, 17-20 days) for the 101 lots released. Updated data to be presented. Conclusions: Our results demonstrate rapid and reliable anito-cel manufacturing for MM clinical trials globally, with high manufacturing success rates and consistent turnaround times. These results were consistent with axi-cel manufacturing outcomes and highlight the importance of leveraging axi-cel manufacturing experience in the development of anito-cel. Clinical trial information: NCT06413498 and NCT07045909 . FP-MSR, n/N (%) 101/102 (99.0) Global mTAT, days (IQR) Lots released, n 18 (17-20) 101