Dr Valtis on Real-World Outcomes Following Treatment With Obe-Cel and Brexu-Cel in R/R ALL

“The question that is very interesting is, how long do those remissions last? Is obe-cel going to result in longer remissions than brexu-cel? I don't know the answer to that. We don't have enough follow up in the ROCCA registry to [say], but that is a very important question. The other very important question, which…we didn't answer with this abstract, is one of those modalities more likely to be curative than the other?”

Yannis K. Valtis, MD, a leukemia specialist and cellular therapist at Memorial Sloan Kettering Cancer Center, discussed real-world outcomes following treatment with obecabtagene autoleucel (obe-cel; Aucatzyl) and brexucabtagene autoleucel (brexu-cel; Tecartus) in patients with relapsed/refractory acute lymphoblastic leukemia (ALL), based on data from the Real-World Consortium of CAR T in Acute Leukemia (ROCCA) registry.

The ROCCA analysis, which was presented at the 2025 ASH Annual Meeting and Exposition, was designed to evaluate patient characteristics, toxicity, and response outcomes following commercial CAR T-cell therapy outside the context of prospective clinical trials. According to Valtis, prior clinical trials and published studies have already established both obe-cel and brexu-cel as highly active agents capable of inducing deep remissions in heavily pretreated patients with relapsed/refractory ALL, supporting prior FDA approvals of both agents. The real-world data presented in this analysis largely corroborated those expectations, he said.

Among patients treated with brexu-cel (n = 54), the rate of measurable residual disease (MRD)–negative complete remission (CR)/CR with incomplete hematologic recovery (CRi) was 80% at day 28 post-infusion, whereas patients treated with obe-cel (n = 38) achieved an MRD-negative CR/CRi rate of 81%. Valtis noted that these high MRD-negative remission rates were not unexpected, given prior trial experience, and reinforced confidence in the efficacy of both CAR T-cell therapies.

However, the more clinically consequential questions remain unanswered. Valtis emphasized that the durability of these remissions is a key area of uncertainty. Specifically, it is not yet clear whether obe-cel may lead to longer-lasting remissions compared with brexu-cel. At present, follow-up within the ROCCA registry is insufficient to draw meaningful conclusions regarding long-term remission duration or relapse patterns.

Another critical unanswered question is whether one CAR T-cell product is more likely than the other to be curative, particularly in relation to the need for subsequent allogeneic hematopoietic stem cell transplantation. Determining whether patients can safely avoid transplant after achieving CAR T-cell therapy–induced remission remains a major area of interest, but current real-world data are not mature enough to address this issue, Valtis concluded.