Real-world outcomes (RWO) with tandem transplantation in patients (pts) with newly diagnosed multiple myeloma (NDMM).

Abstract

7564 Background: Stem cell transplant (SCT) followed by maintenance therapy (MT) is the standard of care for transplant eligible NDMM pts. Tandem transplantation has been found to have progression free (PFS) and overall survival (OS) benefit particularly for patients with high-risk cytogenetic abnormalities (HRCA). However, this modality remains under-utilized in clinical practice. We report RWO with tandem transplant (TT) in comparison with single SCT followed by MT (STM). 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 1st SCT (2nd if TT) 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) model was used to compare study cohorts, and hazard ratios (HRs) were estimated using the Cox proportional hazards method. HRCA were defined as pts with 17p(-), t(4;14), t(14;16), t(14;20) and 1q+. Results: 1117 pts met the study criteria. Median age at diagnosis was 60 yrs. 56.9% were male, 68.9% were White, and 32% had HRCA. 937 pts received STM and 180 pts received TT with median follow-up time of 68 months (mos) (95% CI: 65.4, 71.9) and 39 mos (95% CI: 31.9, 50.1), respectively. Median TTNT1 for TT vs STM was 52.7 vs 51 mos, (p=0.85), respectively. Median TTNT2 for TT vs STM was 33.9 vs 11.8 mos, (p<0.001). respectively. Median OS for TT vs STM was not reached (NR) vs 108.1 mos, (p<0.001), respectively. In the PS model, the TT group had significantly lower hazard of TTNT2 and OS events (HRs 0.49 and 0.47, p<0.001 and p=0.01, respectively) as compared to STM. Conclusions: Our study demonstrates significant improvement in unadjusted TTNT2 and OS RWO for TT pts, despite higher incidence of HRCA compared to STM pts. PS analysis demonstrated a similar effect with decreased HRs for TT. OS is an extremely 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]