Autolus Therapeutics presents longer-term follow-up data analysis of FELIX study

Autolus Therapeutics announces longer-term follow-up and additional data analysis from the pivotal Phase 1b/2 FELIX study of obecabtagene autoleucel in relapsed/refractory adult B-cell Acute Lymphoblastic Leukemia, being presented at the 2024 American Society of Clinical Oncology Annual Meeting. The results of the FELIX trial have been submitted to the FDA as part of a BLA. The PDUFA target action date is November 16, 2024. The ORR in all patients who received obe-cel in the FELIX study was 78%. At the February 7, 2024, data cut-off date, the majority of ongoing responders showed durable responses. Among the responding patients, at a median follow up of 21.45 months, 40% were in ongoing remission without subsequent SCT or other therapy, while 18% proceeded to subsequent SCT while in remission, 5% started new anti-cancer therapy while in remission and 36% relapsed or died. The median event-free survival was 11.9 months and median overall survival was 23.8 months and the estimated 12-month EFS and OS rates were 49.5% and 61.1% respectively. 18 of 99 responders had SCT while in MRD-negative remission. 10 of the 18 had ongoing CAR T persistency prior to SCT, with eight of these 10 patients experiencing relapse or death post SCT. Eight out of 18 (44%) patients had lost CAR T persistency prior to SCT, with five of those eight patients experiencing relapse prior to SCT or death post SCT. Overall, consolidative SCT for patients post-obe-cel did not appear to improve EFS or OS. CAR T persistence and B-cell aplasia were both associated with improved EFS compared with loss of persistency and B-cell recovery. Patients with loss of CAR T persistence had a 2.7 fold increased risk of relapse or death compared to patients with ongoing CAR T persistence. Patients who experienced B-cell recovery had a 1.7 fold increased risk of relapse or compared with patients without B-cell recovery. Among patients with CR/CRi beyond 6 months without SCT or new therapies, patients with ongoing CAR T persistence are associated with improved EFS vs. those with a loss of CAR T persistence. In conclusion these data support the potential of a long-term plateau of survival outcomes in patients receiving obe-cel. At a median follow-up of 21.3 months 40% of responders are in ongoing remission without SCT or other therapy and ongoing CAR T persistence and B-cell aplasia were associated with improved EFS. This pattern is consistent with the Phase 1 ALLCAR19 data. Furthermore, SCT consolidation in remission following obe-cel did not appear to improve EFS or OS.