Treatment Patterns and Outcomes for Patients with Newly Diagnosed Multiple Myeloma Post-Stem Cell Transplantation Who Received Lenalidomide As First Line Maintenance Therapy (PREAMBLE)

Background: For patients with newly diagnosed multiple myeloma (NDMM) who undergo autologous stem cell transplantation (ASCT), lenalidomide (LEN) maintenance is the current treatment standard in both the EU and US (Revlimid US PI 2023). However, as nearly all patients will eventually experience disease relapse, there continues to be significant interest in exploring new strategies to improve upon LEN maintenance. This analysis aimed to characterize patients receiving LEN maintenance post-ASCT, their treatment patterns, and outcomes from a multinational real-world registry. Methods: We analyzed prospectively collected data from NDMM patients post-ASCT who enrolled in the multicenter Prospective REsearch Assessment in Multiple Myeloma: An oBservationaL Evaluation (PREAMBLE) registry. Included patients received a LEN/LEN-containing regimen post-ASCT as maintenance. Key measures included baseline demographic and clinical characteristics and survival outcomes (overall survival [OS] and progression-free survival [PFS]). Results: Of 2206 patients included in the 15 March 2023 data cutoff of PREAMBLE, 668 (30.3%) were diagnosed with NDMM, 203 of whom received ASCT at 1L. After excluding patients who did not receive maintenance therapy post-ASCT (n = 83) and patients who received a maintenance therapy post-ASCT other than LEN (n = 18), 102/203 (50.2%) patients who received LEN as 1L maintenance therapy post-ASCT were included in the analysis. Of these, 75 (73.5%) patients received LEN monotherapy and 27 (26.5%) patients received LEN combination therapy, mostly including bortezomib (18/27 [66.7%]). The number of US-based patients was similar to non-US based patients (54 [52.9%] vs 48 [47.1%], respectively). Median time from diagnosis to initiation of LEN (index date) was 9.3 months, and patients were followed up for a median of 32.9 months (min-max: 0.03-67.8). Most patients (62.7%) were stage I-II at study entry. Median duration of LEN maintenance treatment was 25.0 months (min-max: 0.5-65.1 months). Overall response rate (partial response or better) to LEN index therapy was 70.6% (72/102). At last treatment record, reasons for LEN discontinuation were provided for 61 patients, comprising disease progression (n=18), toxicity (n=15), completed treatment (n=13), maximum clinical benefit (n=2), and other (n=13). In the remaining 41 patients no LEN discontinuation data were provided. Median (95% confidence interval [CI]) PFS was 33.5 (22.6-45.7) months, with the probability of PFS ranging from 87.5% at 6 months to 43.9% at 36 months (Figure). Median OS was not reached, with survival probability ranging from 99.0% at 6 months to 80.6% at 36 months. Conclusion: LEN monotherapy continues to be the main treatment strategy for patients post-ASCT in the NDMM setting with good survival probability over 36 months. However, with more than half of the patients discontinuing treatment as a result of progression/toxicity, there is a need for more effective and tolerable maintenance treatment strategies.