Real-World Survival Impact of CAR T Therapy in Advanced DLBCL: Findings From a SEER Database Analysis
Key Clinical Summary
- Chimeric antigen receptor (CAR) T therapy was associated with a 15-month improvement in median overall survival and a 9% reduction in mortality risk among patients with advanced diffuse large B-cell lymphoma (DLBCL) in a real-world SEER database analysis.
- Findings support earlier integration of CAR T therapy for high-risk relapsed or refractory DLBCL, aligning with outcomes from trials such as ZUMA-7 and TRANSFORM.
- Key implementation challenges include referral timing, manufacturing delays, toxicity management, and ensuring patients are evaluated for CAR T before becoming too frail for treatment.
In this interview, Nishanth Thalambedu, MD, a hematology and oncology fellow at the University of Arkansas for Medical Sciences, discusses his study “Impact of the CAR-T Era on Survival in Diffuse Large B-Cell Lymphoma: A U.S. Population-Based Cohort Study.” The conversation explores how the introduction of CAR T therapy has transformed outcomes for patients with DLBCL, particularly in relapsed or refractory disease. Drawing from SEER database findings, the discussion highlights improvements in overall survival, reductions in mortality risk, and the growing role of CAR T therapy in earlier treatment pathways for high-risk patients.
Nishanth Thalambedu, MD: Good morning, everyone. My name is Nishanth Thalambedu. I'm currently a hematology and oncology fellow at the University of Arkansas for Medical Sciences in Little Rock, Arkansas. As a part of my training, I treat a variety of cancers, both solid tumors and blood cancers. I am also interested in clinical research. My area of focus is mainly database studies to evaluate the survival outcomes and disparities.
Can you give some background about your study and what prompted you to undertake it?
Dr Thalambedu: This study is about DLBCL, which is one of the most common non-Hodgkin lymphomas. Historically, it has very poor outcomes in relapsed and refractory diseases. Once they progress on the frontline chemotherapy, the treatment options are very limited. Usually, these patients are treated with chemotherapy followed by a stem cell transplant.
The initial approval for CAR T therapy happened in 2017. Since then, the treatment landscape has changed significantly. The initial trials—ZUMA-1, JULIET, and TRANSCEND—showed durable remissions and survival benefits. But this has been tested in heavily pretreated populations. And as we know, clinical trial populations are very controlled.
For this study we wanted to evaluate whether these benefits have been translated into real-world population outcomes. So, we used a SEER database and compared patients with advanced DLBCL before and after CAR T implementation. We found a 15-month improvement in the median overall survival and a 9% reduction in the mortality risk. This suggests CAR T has a major population-level impact as well.
Given the observed 15-month improvement in median overall survival at the population level, how should clinical pathways in DLBCL be evolving to incorporate CAR T earlier in the treatment sequence, particularly for high-risk or relapsed patients?
Dr Thalambedu: Our findings supported that incorporating CAR T earlier in the high-risk relapse and refractory DLBCL patients is better when compared to reserving it for later lines of therapy. The subsequent trials, such as ZUMA-7 and TRANSFORM, showed superior outcomes with second-line CAR T treatments compared to the traditional chemotherapy and transplant approaches.
So, clinical pathways should focus on early identification of the high-risk patients, faster referral to the CAR T centers, better coordination between community oncologists and academic centers, and earlier evaluation for patients for CAR T before they become too frail for treatments. Overall, both the clinical trial data and our real-world study support moving CAR T to earlier in the treatment algorithm.
The study shows a 9% reduction in mortality risk independent of age, sex, and race—how do you interpret this in the context of real-world patient selection for CAR T, and what barriers might still be limiting broader impact?
Dr Thalambedu: The reduction in the mortality is significant. It's up to 9%, even after adjusting for age, sex, and race, which suggests the survival benefit is across all demographic differences. This result also aligns with the clinical trials ZUMA-1 and JULIET. However, there are still barriers to CAR T. For instance, at this time, CAR T is being implemented only at major academic centers. The population requiring CAR T access is huge, so not everyone will have a chance to get the treatment. Another barrier is manufacturing delays. From the time a patient has CAR T cells collected to the time of implementation of the CAR T product, there is a delay of 4 to 6 weeks. Depending on the product we use there might be less of a delay, but overall there is a significant delay where the patient might get decompensated and may not be eligible for the CAR T product.
Other barriers include toxicity concerns and referral delays. Although CAR T is a one-shot treatment, it also comes with toxicities that need to be kept in mind for ideal patient selection. Older and underserved patients tend to be under-referred because of their limited access to academic centers that provide this treatment due to transport issues. And finally, insurance and cost challenges also play their parts in accessing the CAR T therapy.
