# Investigating CAR-T Treatment Access for Multiple Myeloma Patients Using Real-World Evidence

## TL;DR

This study finds that access to CAR-T therapy for multiple myeloma varies by race and treatment location, suggesting disparities in care.

## Contribution

The study uses real-world data and a GPT-4 model to uncover racial and geographic disparities in CAR-T therapy access.

## Key findings

- Black patients had lower odds of receiving CAR-T therapy compared to White patients.
- Patients at certain treatment locations had lower odds of receiving CAR-T therapy.
- Some eligible patients had no documented discussions about CAR-T therapy.

## Abstract

Multiple myeloma is a common hematologic cancer in the U.S., with Black patients affected more often than White patients, yet access to new treatments like CAR-T therapy remains limited. This study used real-world data from the University of California health system to examine how disease characteristics, treatment location, and patient demographics are associated with CAR-T therapy receipt. We found that both treatment location and patient-reported race were associated with differences in CAR-T receipt, even after accounting for disease severity and insurance coverage. Using a GPT-4 model to analyze clinical notes, we identified patients eligible for CAR-T therapy who had no documented discussions about it. These findings highlight potential gaps in method of care and provider communication that could limit access to advanced therapies. By uncovering these patterns, this research may help clinicians, health systems, and researchers develop strategies to ensure that patients have better access to receiving advanced treatments.

Importance: Multiple myeloma (MM) is the second most common hematologic malignancy in the U.S., with a higher incidence among Black patients than White patients. Chimeric antigen receptor T-cell (CAR-T) therapies show clinical promise, but their limited availability raises concerns about access. Objective: To examine associations between disease characteristics, treatment location, and patient demographics with receipt of CAR-T therapy among patients with MM. Design: Retrospective cohort study using electronic health record data from the University of California Health Data Warehouse (UCHDW) between January 2021 and January 2025. Setting: Six academic health centers and twelve affiliated hospitals within the UCHDW. Participants: A population-based cohort of 12,360 adult patients diagnosed with MM and treated at a University of California facility offering CAR-T administration. Analyses were conducted from February 2025 to March 2025. Exposures: Receipt of multiple cancer therapies following MM diagnosis. Main Outcomes and Measures: Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between disease characteristics, treatment locations, and patient demographics with receipt of CAR-T therapy. A zero-shot GPT-4 inference model was applied to UCSF clinical notes to assess whether CAR-T therapy was discussed, determine documented eligibility, and classify rationale for eligibility determinations. Results: Among 12,360 patients with MM (mean age, 68.5 years; 51.6% male), 320 (2.6%) received CAR-T therapy. Disease characteristics at diagnosis, measured by the International Staging System (ISS), was distributed as follows: Stage I (65.3%), Stage II (24.4%), Stage III (2.8%), and Unknown (7.5%). Patients treated at UC-1 (49.3%), and UC-2 (50.0%) were more frequently diagnosed with ISS Stage II, whereas patients treated at UC-3 (55.5%) were more frequently diagnosed with ISS Stage I. Our model showed that patients identifying as Black or African American had lower odds of receiving CAR-T therapy compared with White patients (OR, 0.33; [95% CI, 0.17–0.62]). Patients treated at UC-3 also had lower odds of receiving CAR-T therapy compared with UC-1 (OR, 0.42; [95% CI, 0.30–0.59]). Among 270 UCSF patients assessed for CAR-T eligibility using clinical notes, the proportion of patients deemed eligible without documented CAR-T discussions was highest among those identifying as Other Pacific Islander (50%), followed by Black or African American (4.2%), Asian (3.2%), and White patients (0.6%). Conclusions and Relevance: Within a large academic health system, receipt of CAR-T therapy varied by treatment location and patient-reported race. A subset of patients with documented eligibility lacked recorded discussions of CAR-T therapy, suggesting potential differences in referral, documentation, or care pathways influencing observed treatment patterns.