Autolus Therapeutics announces publication of data from FELIX study

Autolus Therapeutics (AUTL) announces that the New England Journal of Medicine has published data from the pivotal Phase 1b/2 FELIX study of obecabtagene autoleucel in relapsed/refractory adult B-cell Acute Lymphoblastic Leukemia. The data demonstrate high rates of durable responses with low incidence of grade greater than or equal to3 immune-related toxicity. Of the 153 r/r B-ALL patients enrolled patients in the FELIX study, 127 received at least one obe-cel infusion and were evaluable. Eligible patients underwent leukapheresis, and bridging therapy, except blinatumomab, was permitted at the investigator’s discretion. Obe-cel was administered in a bone marrow burden adjusted split dose following lymphodepletion, with a BM mandated prior to lymphodepletion to guide dosing. The second obe-cel dose was given in the absence of severe/unresolved toxicity. The primary end point was overall remission. In the pivotal cohort of patients, the CR/CRi for patients who received at least one infusion of obe-cel was 76.6% Across all infused patients, of the 91/127 with greater than or equal to5% BM blasts pre-lymphodepletion, the CR/CRi was 74.7%. Median response duration for all infused patients was 21.2 months. Median event-free survival was 11.9 months and the estimated 6- and 12-month event-free survival rates were 65.4% and 49.5%, respectively. BM burden pre-lymphodepletion correlated with median event-free survival; patients with low, intermediate, and high BM burden had event-free survival rates at 12 months of 68.0%, 54.9% and 25.0%, respectively. Median overall survival was 15.6 months and estimated 6- and 12-month overall survival rates were 80.3% and 61.1%, respectively. BM burden pre-lymphodepletion correlated with overall survival; patients with low, intermediate, and high BM burden had an overall survival rate at 12 months of 71.5%, 58.7% and 55.0%, respectively. BM burden before enrollment also influenced event-free and overall survival. Of the 127 patients infused, 99 patients responded. Of the responders, 18 patients proceeded to allo-Stem Cell Transplant while in remission at a median of 101 days post-obe-cel infusion. In 6/18, this was a second allo-SCT. Of 11 patients who had persisting CAR T cells before allo-SCT, and who had samples available post, none had CAR T cells detected following allo-SCT. There was no difference in event-free and overall survival observed between patients who received allo-SCT and those who did not. Median duration of CAR T persistence by droplet digital PCR in peripheral blood was 17.8 months. Obe-cel was associated with minimal immunotoxicity. CRS and Immune effector cell-associated neurotoxicity syndrome rates were 2.4% and 7.1%, respectively. Overall, 87 patients developed CRS, and 29 developed ICANS. Severe ICANS post-obe-cel were seen as largely limited to patients with high BM burden pre-lymphodepletion. Intensive care unit admissions occurred in 20 patients for a median of 5.5 days of which 7/20 were admitted due to immunotoxicity management. Obe-cel was approved by the Food & Drug Administration under the brand name AUCATZYL on November 8, 2024. Marketing authorization applications for obe-cel are being reviewed by the regulators in both the EU and the UK, with a submission to the European Medicines Agency accepted in March 2024, and a submission accepted by the UK MHRA in August 2024.