Patient (pt) Experiences of Receiving Idecabtagene Vicleucel (Ide-Cel, bb2121) Versus Standard (Std) Regimens for the Treatment (Tx) of Relapsed/Refractory Multiple Myeloma (RRMM) in the Randomized, Controlled KarMMa-3 Clinical Trial: Analysis of Longitudinal Qualitative Interviews

Introduction: Ide-cel is a first-in-class B-cell maturation antigen (BCMA)-directed chimeric antigen receptor T cell therapy approved by the United States (US) Food and Drug Administration; the European Medicines Agency; and Japan's Ministry of Health, Labour, and Welfare for treating adult pts with RRMM who were triple-class exposed (TCE) to an immunomodulatory (IMiD) agent, proteasome inhibitor (PI), and anti-CD38 monoclonal antibody and who experienced disease progression/relapse after last therapy.

The phase 3 multicenter, open-label, randomized controlled KarMMa-3 trial (NCT03651128) enrolled pts with RRMM who were TCE (including an IMiD agent, PI, and daratumumab [DARA]) after 2-4 prior lines of therapy. Pts were randomized 2:1 to receive either ide-cel or 1 of 5 std regimens (DARA, pomalidomide [POM], dexamethasone [DEX]; DARA, bortezomib, DEX; ixazomib, lenalidomide, DEX; carfilzomib and DEX; elotuzumab, POM, DEX). At median follow-up (18.6 mo), median progression-free survival (13.3 vs 4.4 mo) and response rate (71% vs 42%) were significantly higher in the ide-cel versus std regimen arm (Rodriguez-Otero P, et al. N Engl J Med 2023;388:1002-1014). In addition to the standard pt-reported outcomes instruments, trial-embedded interviews provide further insights into the patient Tx experience (Delforge M, et al. J Clin Oncol 2023;41[suppl 16]. Abstract 8032).

This study assessed Tx experience, changes in health-related quality of life, and advantages and disadvantages of assigned Tx for pts enrolled in the KarMMa-3 trial.

Methods: To obtain pts' experiences and perspectives in their own words while on the assigned Tx arms during the study, qualitative interviews were embedded into the KarMMa-3 trial. Pts were randomized (1:4) to participate in a series of optional qualitative interviews conducted at baseline (BL), and 3 and 6 mo post Tx. Interviews were audio-recorded and transcribed. Non-English interviews were transcribed directly into English. Transcripts were analyzed in MAXQDA qualitative analysis software; inter-coder agreement exercises were completed to ensure reliability. Analytic approaches included thematic analysis and longitudinal analysis across aspects of health and well-being.

Results: In total, 64 pts (n = 43 ide-cel, n = 21 std regimen) across 9 countries in Europe and in the USA participated in ≥ 1 interview. Across both arms, 60, 48, and 38 pts completed interviews at BL, and 3 and 6 mo post Tx, respectively. The mean (median) age of interviewed pts at time of consent in the trial was 60.5 (60) years, and 33% were female.

When describing their overall well-being during the previous 4 weeks at 3 mo, 53% of ide-cel pts described their well-being as mostly improved versus 19% in the std regimen arm. In the ide-cel arm, 59% and 56% of pts reported improvements in physical health versus 19% and 10% of pts in the std arm at 3 and 6 mo from BL, respectively; 25% and 28% of pts in the ide-cel arm reported worsening physical health at 3 and 6 mo from BL versus 63% and 80% of pts in the std arm (Table 1). In the ide-cel arm, 47% and 48% of ide-cel pts described improvements in physical functioning at 3 and 6 mo from BL versus 19% and 20% of std regimen pts, respectively; 22% and 16% of pts in the ide-cel arm versus 50% and 60% of pts in the std arm reported worse physical functioning at 3 and 6 mo from BL.

Regarding Tx advantages, ide-cel pts reported efficacy (n = 25, 58%), minimal side effects (n = 21, 49%), avoidance of other therapies (n= 16, 37%), and having a 1-time Tx (n = 12, 28%). Std regimen pts also described efficacy (n = 10, 48%) and minimal side effects (n = 8, 38%) as Tx advantages. Disadvantages discussed by pts treated with ide-cel included lack of efficacy (n = 10, 23%), side effects after infusion (n = 9, 21%), or none (n = 9, 21%). Greater proportions of std regimen pts described side effects (n = 9, 43%) and lack of efficacy (n = 7, 33%). Additional well-being results for both arms are presented in Table 1.

Conclusions: This study provides unique insight into key pt perceptions of ide-cel Tx compared to std regimens. Overall, pts receiving ide-cel reported more positive changes 6 mo post Tx than pts receiving std regimens, specifically in physical health and functioning. Fewer pts treated with ide-cel described side effects than pts receiving std regimens. These data show that ide-cel as a 1-time infusion can alleviate the burden of managing complex medication regimens in TCE early-line relapse pts.