Efficacy and safety of daratumumab, lenalidomide, and dexamethasone (D-Rd) in relapsed or refractory multiple myeloma (RRMM): Updated subgroup analysis of POLLUX based on cytogenetic risk.

8038 Background: High-risk cytogenetic abnormalities confer poor outcomes in MM patients (pts). In POLLUX, D-Rd demonstrated significant clinical benefit, including prolonged progression-free survival (PFS) vs lenalidomide and dexamethasone (Rd), and tolerability in RRMM pts. We present a subgroup analysis of POLLUX, based on cytogenetic risk. Methods: Pts had ≥1 prior line of therapy. Cytogenetic risk was based on a combined analysis of fluorescence in situ hybridization/karyotype testing and next-generation sequencing (NGS). High-risk pts had t(4;14), t(14;16), or del17p abnormalities; standard (std)-risk pts did not meet high-risk criteria. Minimal residual disease (MRD; 10 –5 ) was assessed via NGS using clonoSEQ ® assay V2.0. Results: In POLLUX (D-Rd, n = 286; Rd, n = 283), 17.1% of pts in the D-Rd group and 20.1% of pts in the Rd group had high-risk abnormalities. After 44.3 months (mo) of median follow up, D-Rd prolonged PFS vs Rd in pts with high- (median 26.8 vs 8.8 mo; HR, 0.54 [95% CI, 0.32-0.91]; P = 0.0175) or std-risk (median not reached [NR] vs 19.9 mo; HR, 0.41 [95% CI, 0.31-0.55]; P <0.0001). Responses with D-Rd were deep, including higher rates of MRD negativity and sustained MRD negativity vs Rd (Table). D-Rd prolonged PFS in first relapse pts (high risk: median 46.0 vs 7.3 mo; HR, 0.26 [95% CI, 0.11-0.59]; P = 0.0005; std risk: median NR vs 20.6 mo; HR, 0.43 [95% CI, 0.28-0.66]; P <0.0001) and prolonged PFS2 vs Rd in high- (median 38.3 vs 22.1 mo; HR, 0.53 [95% CI, 0.30-0.93]; P = 0.0249) or std-risk (median NR vs 33.8 mo; HR, 0.53 [95% CI, 0.39-0.72]; P <0.0001) pts. Additional data will be presented. Conclusions: D-Rd demonstrates significant efficacy in high-risk RRMM. Among high-risk pts, MRD negativity was only achieved with D-Rd. Clinical trial information: NCT02076009. [Table: see text]