Access and Outcomes of Minority Health Populations Receiving Commercial Anti-BCMA CART Therapy for Multiple Myeloma

Background: Anti-BCMA chimeric antigen receptor T cell (CART-BCMA) immunotherapy is now a standard treatment for relapsed/refractory Multiple Myeloma (MM) after the first line. However, its widespread use might be limited by the need for access to specialized tertiary care centers and the overall high costs. In this study, we aimed to investigate whether minority health populations (MHP) have equitable access to CART-BCMA and study their outcomes as compared to non-MHP patients (pts).

Methods: MHP were defined as self-reported non-White groups (regardless of ethnicity). Ethnicities were categorized as Hispanic/Latino or non-Hispanic/Latino and analyzed separately.We retrospectively evaluated three cohorts of MM pts:

The first cohort (ACC catchment area cohort) consisted of patients diagnosed with MM in the Abramson Cancer Center (ACC) catchment area between January 2016 and December 2020, accounting for 3,217 cases (from the Pennsylvania, New Jersey, and Delaware cancer registries).

The second cohort (ACC MM cohort) included MM patients who received any form of therapy at the ACC during the same timeframe as the third cohort (June 2021 to October 2023). The total MM cohort comprised 1,747 MM patients with known race, including 1,383 from the catchment area and 364 from outside the catchment area.

The third cohort (CART-BCMA cohort) consisted of the MM pts treated with commercial CART-BCMA at the ACC (122 patients with known race; 71 from the catchment area) between June 2021 and October 2023.

MM diagnosis was identified in the Electronic Medical Records using the International Classification of Diseases (ICD) 10 definition: Multiple myeloma and malignant plasma cell neoplasms (C90.0-90.3). The data collection cut-off date was May 31^st, 2024. Pts were assessed for best response (IMWG modified criteria), progression-free survival (PFS), overall survival (OS), and toxicities (CRS, ICANS, by ASTCT and CTCAE).

Results: In the ACC catchment area cohort, the proportion of MHP was 33.7% (n=1,084/3,217).In the ACC MM cohort, the proportion of MHP patients was 27.3% (n=476/1,747); among those in the catchment area, the proportion of MHP was 30.7% (n=425/1383). In the CART-BCMA cohort, the proportion of MHP pts was 18.0% (n=22/122); considering only patients within the catchment area, the proportion of MHP pts was 23.9% (n=17/71) . Similarly, the proportion of Hispanic/Latino pts also decreased from the catchment area to the CART-BCMA cohort (Catchment: 4.4%, ACC MM: 2.9%, and CART-BCMA: 2.4%).

We analyzed patient outcomes based on MHP status in the CART-BCMA cohort (100 non-MHP and 22 MHP). Patient characteristics were comparable between the two groups, although MHP patients were slightly younger (median age: MHP: 61 y vs. non-MHP 65 y) and received fewer lines of previous therapies (median previous lines: MHP: 6 vs non-MHP: 7) . Overall, 68.1% of MHP patients and 70.7% of non-MHP patients achieved at least a Very Good Partial Response as their best response. The median PFS was 14.7 months for MHP pts and 16.5 months for non-MHP pts. There was no difference in OS between the two groups (Median OS not reached for both groups). No significant differences were observed in the incidence of any grade CRS and ICANS between the two groups (CRS MHP: 91% vs non-MHP patients: 78%, ICANS MHP: 9.1% vs non-MHP: 21%). Due to the limited number of Hispanic/Latino pts, a comparison of clinical outcomes for ethnicity was not pursued.

Lastly, we examined some social determinants that could limit MHP patients' access to CART-BCMA. Travel time from the residence zip code to the CART center was higher for non-MHP patients (median: 63 vs. 35 minutes; 40 vs. 27 minutes including only patients in the catchment area). Additionally, a higher proportion of non-MHP patients treated with CART were married (79.0% vs. 45.5%). Employment status and insurance type were not different based on MHP status.

Conclusion: This study highlights that MHP access to tertiary care for MM is preserved but appears reduced for commercial CART-BCMA, especially for patients outside the catchment area. Nevertheless, when treated with CART-BCMA, MHP patients have similar survival and safety outcomes compared to non-MHP patients. MHP patients receiving CART-BCMA live closer to the CART center and are more commonly unmarried. Therefore, this study highlights the need to establish equitable access to CART-BCMA immunotherapy for diverse populations.