Daratumumab, lenalidomide, and dexamethasone (DRd) vs lenalidomide and dexamethasone (Rd) in relapsed or refractory multiple myeloma (RRMM): Efficacy and safety update (POLLUX).

8025Background: Daratumumab (D) is a human CD38-targeting mAb that significantly prolongs progression-free survival (PFS) when added to standard-of-care regimens in patients (pts) with RRMM. We examined updated efficacy and safety data from POLLUX (NCT02076009), a randomized phase 3 study of DRd vs Rd in RRMM. Methods: Pts with ≥1 prior line of therapy (LOT) received Rd (25 mg PO lenalidomide on days 1-21 of each q4w cycle; 40 mg dexamethasone weekly) ± D (16 mg/kg IV qw for cycles 1 and 2, q2w for cycles 3-6, then q4w until disease progression). Pts refractory to lenalidomide were ineligible. Minimal residual disease (MRD) was assessed on bone marrow samples at time of suspected complete response (CR) and at 3 and 6 months post-suspected CR at sensitivities of 10–4, 10–5, and 10–6 via next-generation sequencing (Adaptive Biotechnologies, Seattle, WA). Results: Pts received a median (range) of 1 (1-11) prior LOT. 55% received prior IMiDs (18% lenalidomide). Based on previous median follow-up of 17.3 month...