Autolus Therapeutics presents positive results from pivotal phase II FELIX study in adult r/r B-ALL at ASCO.

In the pivotal morphological cohort of the FELIX trial, 112 patients with r/r adult ALL were enrolled and 94 (84%) patients were dosed with obe-cel. Of the dosed patients, 76% patients achieved a complete response (CR) or CR with incomplete haematological recovery (CRi), and 97% of the responders with evaluable samples were in deep remission with no detectable minimal residual disease (MRD). Furthermore, at a 9.5-month median follow up, 61% of responders remained in ongoing remission without new anti-cancer therapies. CAR T cellular kinetics demonstrate excellent CAR T engraftment and persistence and are consistent with the prior ALLCAR19 study.

Safety analysis demonstrated a potentially best-in-class tolerability profile with Grade greater than 3 cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) in 3% (3/94) and 7% (7/94) of patients, respectively. Most of the toxicity was seen in patients with high disease burden. Notably, 6 of 7 Grade greater than 3 ICANS were observed among patients with very high tumor burden of more than 75% bone marrow blasts at lymphodepletion. Overall, Grade greater than 3 adverse events occurred in 79% of patients, with neutropenia (36.2%), and thrombocytopenia (25.5%) most commonly reported. Manufacturing was reliable and consistent, with product released for 94% of leukapheresed patients and median turnaround times of 21 days from vein to release.

“We are very encouraged by the outcome of the FELIX study. Obe-cel shows low immunotoxicity, high complete remission rates and excellent CAR T expansion and persistence in adult B-ALL. These data are consistent with the prior ALLCAR19 study and suggest that obe-cel has the potential for long-term clinical benefit in adult B-ALL patients without additional therapies,” said Dr. Claire Roddie, Associate Professor at UCL, Honorary Consultant Haematologist at UCLH.