OBJECTIVES : Combination of bortezomib, melphalan, and prednisone (VMP) is a standard of care for patients with newly diagnosed multiple myeloma, ineligible for stem-cell transplantation (NDMM-TI). While various bortezomib doses have been studied in clinical trials involving VMP, assessment in the real-world (RW) population remains unexplored. Our study aims to evaluate association between change in VMP dosing and overall survival (OS) in NDMM-TI patients identified in RW data sources.

METHODS : NDMM-TI patients were identified from SEER-Medicare (January 2007 - December 2014), OPTUM™ Commercial Claims (January 2000 - March 2017), and OPTUM™ Integrated (January 2007 - March 2016) databases, and were included in the analysis cohort if they had 1) an MM index diagnosis on or after 1 January 2007, 2) medical + prescription coverage at diagnosis, 3) a 1-year look-back period, 4) no prior primary cancers, 5) received ≥1 line-of-treatment and 6) no evidence of stem cell transplantation. VMP exposed patients were categorized into recipients of (i) VISTA dose, if bortezomib was administered twice weekly for ≥2 cycles, and (ii) less intensive modified dose, if bortezomib was administered twice weekly in cycle 1 only, or, once weekly in all cycles. Baseline patient characteristics, comorbidities and OS were compared between the VISTA and modified cohorts.

RESULTS : A total of 7,724 NDMM-TI patients were evaluated. About 1% (N=79) of this cohort received VMP as first line therapy. A majority of the patients received modified dose (78.5%) compared to VISTA dose (21.5%). The modified cohort was significantly younger than the VISTA cohort (mean age 72.3 vs. 76.2 years; P=0.0308). Comorbidity burden was statistically similar in both cohorts. Comparison of modified vs. VISTA cohorts showed similar OS when adjusted for age, renal impairment and CCI-Score (adjusted-HR=1.074 (0.455 - 2.531)).

CONCLUSIONS : Reduced dosing of bortezomib did not change OS among NDMM-TI patients treated with VMP.