CAR-T cell therapy continues to demonstrate significant therapeutic potential in real-world clinical settings, according to new research examining outcomes in diverse patient populations with relapsed or refractory diffuse large B-cell lymphoma (DLBCL). Two complementary studies provide insights into both the efficacy and expanding toxicity profile of this revolutionary immunotherapy.
Real-World Outcomes in Underserved Populations
A comprehensive five-year analysis from the Montefiore Health System in the Bronx examined 79 patients who received axicabtagene ciloleucel (Axi-cel) CAR-T therapy, representing one of the most diverse cohorts reported in CAR-T literature. The patient population was 24% non-Hispanic Black, 33% non-Hispanic White, and 29% Hispanic, with a mean age of 60.86 years.
The study revealed that 50.63% of patients achieved complete remission, 16.46% achieved partial remission, and 22.78% experienced disease progression. These response rates align with previous real-world studies despite the cohort's higher burden of comorbidities, including hypertension (61%), diabetes (32%), and congestive heart failure (23%).
"Our cohort had a comparatively higher prevalence of major comorbidities than those reported in the literature," the researchers noted, with nearly twice the rate of hypertension, triple the rate of diabetes, and quadruple the rate of congestive heart failure compared to other studies.
Mortality and Predictive Factors
The cumulative mortality rates were 10.13% during treatment, 21.52% at one year, 24.05% at two years, and 34.18% at five years post-treatment. Multivariate analysis identified complete remission as the strongest predictor of survival, with patients achieving complete remission showing an 87% reduction in mortality risk (adjusted hazard ratio 0.13, 95% CI [0.04, 0.43]).
Pre-existing comorbidities significantly impacted outcomes. Patients with congestive heart failure had a 5.63-fold increased mortality risk, while those with chronic kidney disease faced a 4.13-fold increase. Elevated lactate dehydrogenase (LDH) levels both before and during CAR-T therapy were also associated with increased three-year mortality risk.
Notably, socioeconomic factors including income quartile and insurance status did not significantly correlate with mortality outcomes, suggesting that CAR-T therapy's benefits may transcend socioeconomic barriers when access is provided.
Toxicity Profile and Management
The study documented high rates of acute complications, with cytokine release syndrome (CRS) occurring in 75.95% of patients and immune effector cell-associated neurotoxicity syndrome (ICANS) in 49.37%. Additional complications included neutropenic fever (58.23%), sepsis (18.99%), and intensive care unit admission (18.99%).
Correlation analysis revealed significant associations between ICANS and CRS, ICU admission, and sepsis occurrence. Pulmonary complications were also significantly correlated with ICU admission and sepsis. Interestingly, Kaplan-Meier survival curves showed delayed survival benefits for patients experiencing CRS and ICANS, with larger differences in survival curves emerging in later years.
Rare and Severe Complications
A separate case series documented three previously unreported severe complications following CAR-T therapy, expanding the known toxicity spectrum beyond typical CRS and ICANS presentations.
The first case involved a 51-year-old woman who developed severe immune-mediated demyelination resulting in quadriplegia. MRI revealed multiple medullary diffusion restrictions and evidence of autoimmune demyelination. Despite treatment with corticosteroids, anakinra, and plasmapheresis, the patient experienced only partial neurological recovery over 210 days, though she maintained complete lymphoma remission.
The second case featured a 63-year-old man who developed large, fluid-filled bullae on both lower extremities on day 10 post-infusion, causing significant ambulation difficulties. The lesions resolved spontaneously by day 31 without specific intervention, and the patient achieved complete remission.
The third case involved bilateral parotid gland enlargement with CT imaging showing symmetric enlargement and numerous small hyperdense nodules. The swelling resolved with standard CRS and neurotoxicity management, and the patient maintained complete remission at one-year follow-up.
Clinical Implications
These findings underscore both the promise and challenges of CAR-T therapy in diverse, medically complex populations. The achievement of durable remissions despite higher comorbidity burdens suggests that CAR-T therapy remains effective outside carefully selected clinical trial populations.
The identification of rare complications highlights the need for enhanced monitoring protocols and expanded toxicity management strategies. The researchers emphasized that "clinicians should be aware of the unique side-effects that uncommonly occur due to CAR-T" as the therapy's use continues to expand.
Cardiac Safety Profile
Detailed cardiac monitoring revealed reassuring safety data, with abnormal troponin-I levels and ejection fraction abnormalities remaining rare both before and after CAR-T therapy. Among 71 treatment survivors, only 6 patients had abnormal troponin-I levels within three months of treatment, and ejection fraction abnormalities were similarly uncommon.
The research contributes valuable real-world evidence for CAR-T therapy implementation in diverse healthcare settings, particularly those serving medically underserved populations. While the higher toxicity rates observed may reflect the complex medical backgrounds of treated patients, the achievement of durable remissions supports continued expansion of CAR-T access to broader patient populations with appropriate supportive care infrastructure.
