Obe-cel demonstrates strong efficacy and safety in treating leukemia

Patients with relapsed or refractory CD19-positive B-cell acute lymphoblastic leukemia (ALL) who were treated with the novel anti-CD19 chimeric antigen receptor (CAR) T cell therapy, obecabtagene autoleucel (obe-cel), experienced high response rates and most did not need a subsequent stem cell transplant (SCT), according to results from the Phase Ib/II FELIX trial co-led by researchers at The University of Texas MD Anderson Cancer Center.

The findings, published today in the New England Journal of Medicine, showed a 76.6% response rate and 55.3% complete remission rate in 127 evaluable patients. The median event-free survival (EFS) was 11.9 months, and the EFS rates at six and 12 months were 65.4% and 49.5%, respectively. The median overall survival (OS) for infused patients was 15.6 months. At six and 12 months, the estimated OS rates were 80.3% and 61.1%, respectively.

Based on these data, the Food and Drug Administration approved obe-cel for the treatment of relapsed or refractory B-cell ALL in adult patients in Nov. 2024. Additional findings from the study will be presented Dec. 9 at the 2024 American Society of Hematology (ASH) Annual Meeting by Elias Jabbour, M.D., professor of Leukemia and the study's U.S. lead investigator.

"Patients with B-cell ALL need effective standalone treatment options, and obe-cel demonstrated strong long-term efficacy and response rates in patients treated on the FELIX study," Jabbour said. "Until now, these patients had limited treatment options. We observed minimal immunotoxicity and a strong persistence of CAR T cells, which support obe-cel being the standard of care for this population."

The global, multi-center FELIX trial treated 127 adults with relapsed or refractory B-cell ALL. Prior to receiving obe-cel, trial participants had lymphodepletion – an important step to eliminate existing T cells and create a blank slate for CAR T cell therapy – followed by obe-cel infusion in split doses on days one and 10. The median age of trial participants was 47 years and 52% were male. Patients were 74% white, 12.6% Asian, 1.6% Black and 11.8% unknown.

Toxicities were mostly limited to patients with high bone marrow burden. Patients experienced a low grade of cytokine release syndrome (CRS) and neurotoxicity, which are associated with CAR T cell therapies. Three patients experienced CRS symptoms of grade 3 or higher, and nine patients experienced immune effector cell-associated neurotoxicity syndrome of grade 3 or higher. Observed side effects were consistent with previous studies, and no new adverse effects were identified.

Among the 99 patients who responded to obe-cel, only 18 went on to receive a SCT while in remission at a median of 101 days after their infusion. Researchers observed no difference in EFS and OS between patients who received a SCT and those who did not, suggesting a durable response from obe-cel therapy.

The trial also demonstrated significant clearance of minimal residual disease (MRD) following obe-cel treatment. In patients with blood cancers, MRD refers to a small number of cancer cells remaining after treatment that have the potential to cause relapse.

On the study, 68 high-risk patients – defined as those with bone marrow blasts greater than 5% prior to lymphodepletion – achieved a complete remission. In this group, 62 patients had MRD data available, and 58 patients were MRD-negative after obe-cel infusion.

In the upcoming ASH presentation, Jabbour will highlight the correlation between depth of MRD-negative remission and clinical outcomes in patients treated with obe-cel. Prior to lymphodepletion, researchers evaluated patient bone marrow samples by next generation sequencing (NGS). The findings indicate lower levels of MRD were associated with a stronger response, including higher EFS and OS rates, Jabbour explained.

Comments

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment
Post

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Overcoming challenges in developing cell therapies for heart disease