Rodríguez‐Otero, Paula

8032 Background: Patients (pts) with TCE RRMM have few treatment (Tx) options and poor HRQoL. Ide-cel, the first in class CAR T cell Tx for pts with TCE RRMM, improved PFS versus standard (std) regimens in the KarMMa-3 trial. We report the PRO results comparing the Tx arms. PROs provide further understanding of Tx benefit of ide-cel from the pts’ perspective. Methods: KarMMa-3 (NCT03651128) is an open-label phase 3 RCT comparing the efficacy and safety of ide-cel with std regimens in pts with TCE RRMM, who had received 2–4 prior regimens. In addition to clinical endpoints, we evaluated the impact of ide-cel compared with std regimens on the changes in HRQoL, measured by the EORTC QLQ-C30, EORTC QLQ-MY20, and the EQ-5D-5L questionnaires. PROs were collected at baseline (screening), day of infusion and monthly from 2–24 months (mo) and thereafter every 3 mo. This interim analysis reports PROs through 20 mo. Comparisons were performed on least squares mean (LSM) changes from baseline over time between arms using constrained longitudinal data analysis (cLDA). Results: In total, 386 pts were randomized (ide-cel, 254; std regimens, 132). PRO compliance was high over time ( > 80%). At baseline, PROs were similar between arms. LSM changes from baseline to 20 mo showed significant differences ( P < 0.05), with effect sizes of 0.3–0.7, in favor of ide-cel for most domains, including global health status/QoL, cognitive functioning, fatigue, and pain (EORTC QLQ-C30); side effects of Tx (EORTC QLQ-MY20); and the EQ-5D-5L VAS. The difference in overall LSM change reached or exceeded the pre-specified between-groups minimal importance difference (MID) for improvement in most domains in favor of ide-cel (Table). Conclusions: Ide-cel showed statistically significant and clinically meaningful improvements in HRQoL, including key MM symptoms and functioning, for pts with TCE RRMM compared with std regimens. The PRO data for ide-cel expands upon the clinical outcomes observed in the KarMMa-3 trial. Clinical trial information: NCT03651128 . [Table: see text]