Sandin, Rickard

7532 Background: BsAbs are highly effective, off-the-shelf T-cell engagers recently approved for relapsed/refractory multiple myeloma (MM) but remain underutilized in real-world settings. In partnership with the Florida Society of Clinical Oncology (FLASCO), a statewide initiative was launched to expand BsAb access through peer-led regional discussions focused on operational barriers, care transitions, and therapy management strategies. This study assessed the real-world impact of these interventions on BsAb utilization in FL. Methods: Multidisciplinary discussion forums were held in 4 FL metropolitan areas (Jan-Apr 2024). We conducted single and controlled interrupted time series (ITS) analyses using IQVIA eLAAD claims data (Apr 2023 - Sep 2025) including adult patients with a diagnosis of MM, evidence of claim activity, and provider state information. Fifth line or later (5L+) status was estimated as 3.3% of MM prevalence (Nikolaou et al.) BsAb utilization (% of MM 5L+ patients receiving a BsAb) was evaluated using segmented regression to estimate pre- and post-intervention trends, excluding the intervention period. We reported BsAb utilization by comparing FL with all other states, between community versus academic settings, and assessing the number of sites administering BsAb. Results: Before the intervention, BsAb utilization among MM 5L+ patients in FL rose from 8.2% (Apr 2023) to 11.2% (Dec 2023) (0.3 pp/mo; p=0.23), compared with a rise from 6.7% to 16.3% (1.3 pp/mo; p<0.0001) across all other states over the same time period. Post-intervention, BsAb utilization in FL increased from 22.8% (May 2024) to 35.9% (Sep 2025), reflecting a 7.0% immediate increase and 0.8 pp/mo sustained growth, exceeding the post-intervention trend observed across all other states (23.5% to 30.3%; 0.5 pp/mo). Overall, although pre-intervention BsAb utilization in FL was lower than all other states, FL demonstrated a 1.2 pp/month higher post-intervention utilization trend (p<0.001; Table). Post-intervention, FL community sites showed a 0.13 pp/mo higher BsAb utilization trend than academic sites, and the number of community sites administrating BsAb increased from 5 to 9, with no change among academic sites. Conclusions: This study suggests that the FLASCO-led, collaborative model increased BsAb utilization in FL community oncology sites and offers a framework for broader community adoption across other states. Parameter estimates from ITS model(s). FL (%) p-value Other US States (%) p-value Difference CITS:FL - Other US States (%) p-value Intercept (Apr 2023) 8.6 <.0001 7.7 <.0001 0.9 0.52 Monthly change pre-intervention 0.3 0.23 1.3 <.0001 -0.9 0.002 (Apr - Dec 2023) Immediate change post-intervention 7 0.01 0.2 0.87 6.8 0.01 (May 2024) Monthly change post-intervention 0.8 <.0001 0.5 <.0001 1.2 0.0003 (May 2024 – Sep 2025)

BACKGROUND Several studies have highlighted the poor clinical outcomes observed among patients with relapsed/refractory multiple myeloma (MM), particularly those with triple-class refractory (TCR; refractory to at least one protease inhibitor [PI], one immunomodulatory drug [IMiD], and one anti-CD38 monoclonal antibody [mAb]) disease. The aim of this study was to describe the longitudinal changes in quality of life (QOL) and other patient-reported outcomes (PROs) among TCR MM patients who initiated a new line of therapy in real-world clinical practice. METHODS A prospective, multi-site observational study was conducted through the Mayo Clinic system. Patients with TCR MM initiating a new line of therapy (defined as the index date) were followed for a 12-month observation period. For patients initiating a CAR-T therapy, PRO survey assessments were conducted at apheresis, lymphodepletion chemotherapy, and every month after T-cell infusion until Month 6. All other patients received a survey assessment before index and every month thereafter until Month 6. PRO measures included the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ-C30; including the Global Health Score [GHS]), the EORTC Multiple Myeloma Questionnaire (QLQ-MY20; including the Disease Symptoms [DS] domain score), the EORTC QLQ for Chemotherapy-Induced Peripheral Neuropathy (CIPN20), the EuroQoL-5 Dimensions (EQ-5D), the Patient Global Impression of Severity (PGIS), and the Patient Global Impression of Change (PGIC). PRO surveys were supplemented with retrospective chart reviews conducted at 3 months and 12 months following the index date to obtain clinical information. Descriptive data were reported at each timepoint separately for patients who received CAR-T and non-CAR-T index therapies. The study is ongoing and this abstract reflects all patient data collected as of May 2024. RESULTS This interim analysis included 77 patients (58% male, 95% White, mean age 66 years). The median time interval between becoming TCR and the index date was 5.6 months (interquartile range [IQR]: 1.8, 18.2). Most patients had an Eastern Cooperative Oncology Group (ECOG) score of 0 or 1 (48% and 45%, respectively) and were Revised International Staging System (R-ISS) I or II (27% and 36%, respectively); 42% of patients had high-risk cytogenetics and 14% had extramedullary disease. The median (IQR) number of prior treatment lines was 4 (4, 5). Forty-two patients initiated a CAR-T therapy as their index therapy (12 and 30 treated with ide-cel and cilta-cel, respectively); the remaining 35 patients predominantly initiated a treatment regimen containing an IMiD (51%), a PI (54%), an anti-CD38 antibody (40%), or an alkylating agent (37%). Among these non-CAR-T patients, common regimens used were pomalidomide + elotuzumab + corticosteroids (26%), carfilzomib + cyclophosphamide + corticosteroids (20%), and pomalidomide + carfilzomib + corticosteroids (17%). Among CAR-T patients, QOL generally remained stable from apheresis (mean GHS and EQ-5D VAS were 62.3 and 66.4, respectively) to lymphodepletion (61.2 and 65.9) to Month 6 (64.2 and 68.9). Disease symptoms improved (mean DS domain scores at apheresis, lymphodepletion, and Month 6 were 25.7, 24.1, and 20.1, respectively) though pain, specifically, plateaued/worsened (mean pain domain scores were 24.5, 32.1, and 32.6). Based on the PGIC, 76% of patients reported being “a little better” or “much better” as early as Month 1, which stabilized over time (75% at Month 6). Among non-CAR-T patients, QOL largely remained stable (GHS and EQ-5D VAS was 62.9 and 68.4, respectively, at baseline and 64.9 and 67.7 at Month 6), though disease symptoms, including pain, improved over time (DS was 28.0 at baseline and 22.8 at Month 6; pain was 40.8 at baseline and 28.1 at Month 6). Based on the PGIC, 30.7% of patients reported being “a little better” or “much better” at Month 1, which improved to 52.7% by Month 6. CONCLUSIONS In this interim analysis of an ongoing prospective observational study, baseline values suggest a significant QOL burden among TCR patients. QOL generally remained stable for both CAR-T and non-CAR-T patients over the first several months post-therapy with some select improvements in disease symptoms. However, the patients (particularly CAR-T patients) directly reported some holistic improvement based on the PGIC as early as Month 1.