Comparative Effectiveness Research for CAR-T Therapies in Multiple Myeloma: Appropriate Comparisons Require Careful Considerations of Data Sources and Patient Populations.

Background And Objective: Registrational trials for ciltacabtagene autoleucel [cilta-cel]) and idecabtagene vicleucel [ide-cel] chimeric antigen receptor T-cell (CAR-T) therapies were single-arm studies conducted with relapse refractory multiple myeloma (MM) patients who were triple-class-exposed (TCE) or triple-class-refractory (TCR). It is critical for researchers conducting comparative effectiveness research (CER) to carefully consider the most appropriate data sources and comparable patient populations. The aim of this study was to identify potential data sources and populations for comparing to single-arm CAR-T trials CARTITUDE-1 (cilta-cel) and KarMMa (ide-cel).

Methods: A 2-part global systematic literature search produced a review of (1) clinical trials of National Comprehensive Cancer Network (NCCN) guideline preferred regimens in previously treated MM, and (2) real-world data cohorts of TCE or TCR populations, published between 1/1/2015 and 12/10/2020, with sample sizes of > 50 patients and reporting survival-related outcomes. Implications on CER and accepted best practices are discussed.

Results: Nine clinical trials of NCCN preferred regimens were identified along with five real-world data-based publications. No clinical trials evaluated patients with TCE or TCR MM. Among the real-world data-based publications, two evaluated patients exclusively with TCR MM, two analyzed a mixed population of patients with TCE or TCR MM, and one publication assessed patients exclusively with TCE MM. Real-world data treatment patterns were heterogeneous.

Conclusion: Current NCCN preferred regimens were not specifically studied in TCE or TCR MM patients, although some studies do include a proportion of these types of patients. Therefore, appropriate matching of populations using either real-world data or patient level clinical trial data is critical to putting trials of novel CAR-Ts (i.e., CARTITUDE-1 or KarMMa) into appropriate comparative context.