Extended analysis shows long-term benefit with obe-cel in relapsed or refractory B-ALL

Patients with relapsed or refractory B-cell acute lymphoblastic leukemia who responded to treatment with obecabtagene autoleucel (obe-cel) demonstrated long-term survival benefits regardless of initial best overall response, according to an analysis of the phase 1b/2 FELIX trial.

The analysis, led by Elias Jabbour, MD, of the University of Texas MD Anderson Cancer Center in Houston, will be presented during the poster session at the Fourteenth Annual Meeting of the Society of Hematologic Oncology in Houston, Texas.

Obe-cel is an autologous CD19–directed chimeric antigen receptor T-cell therapy designed to reduce severe immunotoxicity. In the FELIX trial, 127 patients received obe-cel infusion, of which 78% achieved remission. Of these, 73.7% achieved complete remission and 26.3% achieved CR with incomplete hematological recovery at any time after infusion. Investigators noted median bone marrow blasts at screening was 78.5% in patients with CRi compared with 30% in patients with CR.

After a median study follow-up of 32.8 months (range, 19.9-52.8), the median event-free survival (EFS) was 44.6 months (95% CI, 15.1-not evaluable [NE]) in the CR group and 6.1 months (95% CI, 2.9-NE) and in the CRi group. The 24-month EFS rates were 57.9% in the CR group and 41.5% in the CRi group. The median overall survival was 44.6 months (95% CI, 23.8-NE) in the CR group and 11.9 months (95% CI, 6.7-28.8) in the CRi group, and 24-month OS rates were 62.1% and 38.5%, respectively.

In a follow-up analysis of 75 patients with ongoing remission at month three, 68% had CR and 32% had CRi. Median EFS was NE in either group, and median OS was 44.6 months (95% CI, 17.9-NE) in the CR group and 44.6 months (95 CI, 27.6-NE) in the CRi group. The median platelet and neutrophil count recovery time was within one month after infusion. Four patients with CRi at month three had persistent thrombocytopenia at month six, but did not develop bleeding events.

Reference

Jabbour E, Park JH, Shah BD, et al. Clinical outcomes in adult patients with relapsed/refractory acute lymphoblastic leukemia who achieved remission following treatment with obecabtagene autoleucel in the FELIX study. Abstract ALL-706. Presented at the 2026 Society of Hematologic Oncology Annual Meeting; September 9-12, 2026; Houston.