P945: real-world clinical outcomes among triple-class exposed relapsed refractory multiple myeloma patients in us and europe: a preamble registry study

Topic: 14. Myeloma and other monoclonal gammopathies - Clinical Background: Despite recent treatment advances in multiple myeloma (MM), it remains an incurable disease, and a significant proportion of patients eventually relapse or become refractory to their latest treatment. Limited information is available on real-world treatment patterns and clinical outcomes in triple-class exposed (TCE; i.e. exposed to immunomodulatory drugs, proteasome inhibitors, and anti-CD38 antibodies) relapsed/refractory MM (RRMM) patients, a population with high unmet need. Aims: The objective of this analysis was to describe treatment patterns and clinical outcomes (overall survival [OS]; progression-free survival [PFS]; time to progression [TTP]; event-free survival [EFS]), which included progression, subsequent treatment, or death from any cause as events) in patients with TCE RRMM in real-world clinical practice. Methods: We analyzed prospectively collected data from the multicenter Prospective REsearch Assessment in Multiple Myeloma: An oBservationaL Evaluation (PREAMBLE) registry [NCT01838512]. PREAMBLE registry includes patients with newly diagnosed MM and RRMM in Europe and the United States (US). The current analysis was conducted in the population of patients enrolled in PREAMBLE who were TCE. The earliest available end date of third treatment class was considered the date patients became TCE. If patients received a subsequent line of therapy (LOT) after the TCE date, the first subsequent LOT was defined as index treatment, which start date defined the index date. The TCE RRMM study identification period was 16-Nov-2015 to 31-Dec-2020. Patients were analyzed across two cohorts: TCE cohort (all TCE patients with or without index treatment) and post-TCE cohort (those patients who received ≥1 additional LOT after becoming TCE). Results: Of the 2,206 patients enrolled in PREAMBLE, 377 were eligible for TCE RRMM analysis (including 194 post-TCE patients). Patients’ location was evenly split between Europe and the US (51.5% and 48.5%, respectively). Patients in the TCE and post-TCE cohort had a median age of 70.0 and 69.0 years. The majority were male (56.5% and 53.6%, respectively), and most patients were white (79.3% and 78.4%, respectively). Median length of follow-up from TCE date was 7.0 months (standard deviation [SD], 10.7) in the TCE cohort and 11.1 months (SD, 10.9) in the post-TCE cohort. Median length of follow-up from index date was 10.0 months (SD, 10.6). OS was 16.2 months (95% CI 13.5, 23.5) for the TCE cohort, and 18.3 months (95% CI 14.0, 25.9) for the post-TCE cohort. For the post-TCE cohort, PFS was 4.9 months (95% CI 3.5, 5.8), TTP was 6.0 months (95% CI 4.9, 7.4) and EFS was 4.9 months (95% CI 3.6, 5.9). Summary/Conclusion: This real-world study is focused on a TCE RRMM population with a high unmet need. Despite new treatment advances, RRMM patients following TCE had poor clinical outcomes. Treatment patterns and clinical outcomes data from this real-world study highlight the need for novel more efficacious treatments for TCE RRMM patients. Figure: Progression Free Survival (PFS) in patients receiving subsequent LOT post-triple-class exposureKeywords: Survival, Real world data, Clinical outcome, Multiple myeloma