Where does obe-cel currently fit in the treatment algorithm for B-cell ALL, and how might this evolve?

The ALL Hub was pleased to speak with Claire Roddie, University College London Cancer Institute, London, UK. We asked, where does obecabtagene autoleucel (obe-cel) currently fit in the treatment algorithm for B-cell acute lymphoblastic leukemia (B-cell ALL), and how might this evolve? 

In this interview, Roddie discusses the current regulatory approvals for obe-cel for the treatment of B-cell ALL and the key findings from the phase Ib/II FELIX trial. Roddie also outlines the evolving role of obe-cel in the treatment of ALL, including an ongoing study investigating its use earlier in the treatment paradigm, and concludes by highlighting the importance of developing biomarker assays to monitor patients following CAR T-cell infusion.  

Key points  

• Obe-cel is an autologous, anti-CD19 CAR T-cell therapy that was approved by the U.S. Food and Drug Administration (FDA) for the treatment of adults with relapsed/refractory (R/R) B-cell precursor ALL in November 2024.¹ 
• In July 2025, obe-cel was granted marketing authorization by the European Commission (EC) for the treatment of patients ≥26 years old with R/R B-cell precursor ALL.²  
  • In November 2025, NICE recommended obe-cel for routine NHS use in England to treat adults ≥26 years with R/R B-cell precursor ALL.^3,4 
• Approval of obe-cel is based on results from the phase Ib/II FELIX trial (NCT04404660), which demonstrated a high incidence of durable responses and low incidence of Grade ≥3 immune-related toxicity in adult patients with R/R B-cell ALL.^5,6 
  • In Cohort 2A, for patients with morphological disease (n = 94; median follow-up 20.3 months), overall remission occurred in 77% of patients who received at least one infusion of obe-cel (95% confidence interval [CI], 67–85); 55% of patients achieved complete remission (95% CI, 45–66), and 21% achieved complete remission with incomplete hematological recovery (95% CI, 14–31).⁵ 
  • In patients who received at least one obe-cel infusion (n = 127), the median response duration was 21.2 months (95% CI, 11.6 to not evaluable), and the median event-free survival was 11.9 months (95% CI, 8.0–22.1).⁵ 
  • Grade ≥3 cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) occurred in 3 patients (2.4%) and 9 patients (7.1%), respectively.⁵ 
• In the follow-up analysis of patients studied for ≥3 years, 40% of responders were in ongoing remission without subsequent stem cell transplant (SCT) or other new therapies.⁶ 
• A multivariate analysis of data from the FELIX trial demonstrated that lower disease burden at lymphodepletion (LD) and earlier obe-cel use were associated with better outcomes and longer survival in adult patients with R/R B-cell ALL.⁶ 
• Building on these findings, ongoing phase II clinical studies are investigating obe-cel in different ALL settings, including its earlier use in the disease course as consolidation therapy for newly diagnosed high-risk B-cell ALL (NCT07053059) and as consolidation therapy in adults with ALL in first complete remission without measurable residual disease (NCT07400029).^7,8 
  • Earlier administration of CAR T-cell therapy may may improve T-cell product quality, as the starting T-cell population may be less affected by prior cytotoxic treatments.⁹ 
• Monitoring CAR-T cell expansion and persistence with assays like droplet digital PCR (ddPCR) and flow cytometry is essential for guiding patient management after obe‑cel infusion, supporting the development of a biomarker-driven approach to guide clinical decisions after obecel infusion.¹⁰ 

In summary, recent approvals have introduced obe-cel as a new CAR T-cell therapy for the treatment of adults with R/R B-cell precursor ALL that is well tolerated and demonstrates durable long-term responses in a subset of patients. Ongoing studies continue to evaluate its optimal use across different disease settings. 

This educational resource is independently supported by Autolus. All content was developed by SES in collaboration with an expert steering committee. Funders were allowed no influence on the content of this resource.