Effect of maintenance therapy (MT) on real-world outcomes (RWO) of patients (pts) with newly diagnosed multiple myeloma (NDMM) post stem cell transplant (SCT).

Abstract

7562 Background: SCT followed by MT is the standard of care for pts with transplant-eligible (TE) NDMM. Five randomized clinical trials (RCTs) comparing lenalidomide MT versus no MT showed improved progression free survival (PFS), but no overall survival (OS) benefit except for one by McCarthy et al. that allowed pt crossover between treatment arms. Use of MT has also been associated with an increased risk of second primary malignancies and an inferior quality of life. We report RWO post SCT with and without MT in TE NDMM. Methods: We performed a multi-center, retrospective, observational study using the de-identified COTA real-world database derived from the EMRs of US centers. Pts with NDMM from 1/1/2012 to 1/1/23 were included in the study. Kaplan-Meier method was used to evaluate time to next treatment (TTNT), OS, follow-up time (reverse OS endpoint), and report log-rank test p-values. TTNT was defined in two ways: time from SCT to the earliest of initiation of next line of therapy (LOT) or death (TTNT1) and the time from 2nd LOT post-SCT to the earliest of initiation of next LOT or death (TTNT2). A propensity score (PS) matched analysis was used to compare study cohorts and report hazard ratios (HRs) using the Cox proportional hazards method. High risk cytogenetic abnormalities (HRCA) were defined as pts with 17p(-), t(4;14), t(14;16), t(14;20) and 1q+. Results: 1928 ptsmet the study criteria: 957 pts received SCT with MT (M) and 971 pts received no MT (NM). Median age at Dx was 61 y, 57% were male, 70% were White, and 31.2% had HRCA with a median follow-up of 64 months (mos) (95% CI: 61.6, 66.7). In the M vs NM arms, 29.6% and 32.7% pts had HRCA, respectively. Median TTNT1 for M vs NM was 51 vs 36 months (mos), (p<0.001), respectively. Median TTNT2 for M vs NM was 11.7 vs 21.6 mos, (p<0.001), respectively. Median OS for M vs NM was 108.8 mos vs 126.3 mos, (p=0.08), respectively. In the PS model, the NM group had significantly lower hazard of TTNT2 and OS events (HRs 0.65 and 0.85, p<0.001 and p=0.08, respectively). Conclusions: Our study demonstrates improved TTNT2 outcomes with the NM approach. M therapy did not have an impact on OS in this cohort. Both results indicate an absence of long-term benefit with the use of M therapy. OS is a difficult primary outcome to achieve in MM RCTs where survival may have to be collected for decades. Thus, our large study of RWO with long-term follow-up is valuable. [Table: see text]