Real-world outcomes of inaticabtagene autoleucel in Chinese patients with B-ALL.

6529 Background: Inaticabtagene autoleucel (Inati-cel) is a CD19-specific chimeric antigen receptor (CAR) T-cell product, featuring a CD19 scFv derived from the clone HI19α and a 4-1BB/CD3-ζ costimulatory domain, which was approved in China for adult patients with relapsed or refractory B-acute lymphoblastic leukemia (r/r B-ALL) in November 2023. Methods: We conducted the multi-center, non-interventional real-world study (NCT06450067) to evaluate Inati-cel for adult B-ALL patients. Between November 20, 2023, and November 13, 2024, 62 patients received Inati-cel and were evaluable. The median age was 37.5 (range, 14-76) years, with 13 patients aged≥60 years. At screening, 16 cases relapsed after hematopoietic stem cell transplantation (HSCT), 4 cases were primary refractory, and over 70% of patients carried high-risk genetic abnormity. The median infusion dose was 0.60 (range: 0.46-0.9) ×10 8 CAR-T live cells. Results: The data as of December 30, 2024, with a median follow-up of 3.8 months (range: 0.5–12.4 months), 89.5% achieved MRD-negative ORR after Inati-cel in r/r patients, including 31 with CR and 3 with CRi (table1). Nine patients with MRD-positive at screening, the MRD-negativity rate reached 100% after Inati-cel. After Inati-cel, 26 patients had MRD results detected by q-PCR, and 92.3% obtained negative results. After achieving CR/CRi, 4 patients subsequently underwent allo-HSCT in remission. The median DOR, OS and RFS have not been reached with and without censoring patients at subsequent allo-HSCT. Among the evaluable patients, the 1-year RFS and DOR rates were 76.2% and 74.1%, respectively. Seven patients experienced relapses, including 3 CD19+ relapses, 2 CD19- relapses, and 2 with unclear CD19 status. It is worth noting that in 6 cases of extramedullary disease, 4 cases were effective, but 2 cases relapsed within 3 months after Inati-cel. All patients who received the Inati-cel infusion were alive, except for one death from disease progression. The most common adverse events (AEs) of special interest were cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Fifty-one percent of patients developed CRS, but grade 3 or higher CRS and ICANS only occurred in 3.2% and 1.6% of patients, respectively; all patients recovering without sequelae, no AE-related deaths. Conclusions: The real-world use of Inati-cel demonstrates a high MRD-negative ORR in adult B-ALL. The safety profile was manageable, with a low incidence of grade ≥3 CRS and ICANS in the real-world setting. Longer follow-up data will be presented. Clinical trial information: NCT06450067 . Efficacy profiles treated with Inati-cel. Response r/r B-ALL at enrollment，n=32 isolated extramedullary disease, n=6 MRD-pos, n=4 MRD-neg, n=20 CR or CRi （No. of patients） 30 4 - - Rate 93.7% 66.7% - - CR, No. (%) 27(84.3%) 4(66.7%) - - CRi, No. (%) 3 (9.4%) - - - MRD-neg rate,No. (%) 30/30 (100%) - 4/4 (100%) - 1-year DOR rate 67.4% 93.3% 1-year RFS rate 68.2% 93.8%