Abstract PO-111: The impact of race, ethnicity and obesity on CAR T-cell outcomes

Abstract

Introduction: Chimeric antigen receptor (CAR) T-cells have revolutionized therapies for B-cell malignancies. However, while ethnic and racial minorities or those with obesity represent medically underserved populations for whom cancer outcomes are worse, it is unknown whether these factors also negatively impact outcomes of CAR T-cells. Methods: We conducted a retrospective review of 5 unique phase I CAR T-cell trials for children and adults with B-cell malignancies (including CD19, CD22 and BCMA targeted CAR T-cells for B-cell acute lymphoblastic leukemia (B-ALL), B-cell non-Hodgkin lymphoma (NHL) and multiple myeloma (MM)). In addition to evaluating basic demographics, complete remission (CR) rates and cytokine release syndrome (CRS) severity, graded by ASTCT, were stratified by race (white vs non-white), ethnicity and obesity, defined as BMI > 30. All individual protocols were IRB approved, and the retrospective study for this analysis is registered at: Clinicaltrials.gov NCT03827343. Statistics were done in GraphPad Prism, using non-parametric tests with p<0.05 considered significant. Results: 185 patients were treated with 1 of 5 unique CAR T-cell constructs. The median age was 22.7 years (range, 4.2-69 years). 138 had B-ALL; 23 had NHL and 24 had MM. The racial distribution was 154 (83.2%) white patients, and 31 (16.8%) non-white patients. The ethnic distribution (Hispanic versus non-Hispanic) was: 45 (24.3%) Hispanic, 139 (75.1%) non-Hispanic, and 1 unknown. Twenty-eight patients (15.1%) were obese. CR rates in those with B-ALL was 68.1% (94/138), in MM was 8.3% (2/24), and in NHL was 43.5% (10/23). CR rates did not vary by race or ethnicity. White CR rate 88/154 (57.1%) vs non-white CR rate was 18/31 (58.1%); p=not-significant (NS)) Hispanic CR rate was 26/44 (59.1%) vs Non-Hispanic CR rate of 79/136 (58.1%); p=NS. The overall CR rate in obese patients was 50% (14/28) versus 58.6% (92/157) in non-obese patients, p=NS. Grade >/= 3 CRS occurred in 35/185 (18.9%) patients and did not vary by race. Grade >/= 3 CRS in white patients was 30/154 (19.5%) vs non-White patients was 5/31 (16.1%); p=NS. Rates of Grade >/= 3 CRS were higher in Hispanic patients, (13/45, 28.9%) versus non-Hispanic patients (21/139, 15.1%), p=0.05 and in obese patients, (9/28, 32.1%) vs non-obese 26/157 (16.6%); p=NS). Conclusion: While CR rates did not vary by race (white versus non-white), ethnicity or obesity, a closer analysis by racial sub-populations and at active dose levels is a critical next step to evaluate for subtle disparities. Hispanic patients and those with obesity had a trend towards higher rates of Grade >/= 3 CRS, which needs further study. Given the tremendous potential of CAR T-cells across diverse populations and ability to overcome chemotherapeutic resistance seen in minority populations, CAR T-cells may represent an opportunity to improve outcomes for underserved populations without substantially increasing toxicity. Citation Format: Paul Borgman, John Ligon, Bonnie Yates, Haneen Shalabi, Toni Foley, Lauren Little, Jennifer Brudno, Lekha Mikkilineni, James Kochenderfer, Nirali N. Shah. The impact of race, ethnicity and obesity on CAR T-cell outcomes [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-111.