7502 Background: In the primary analysis of the phase 3 PERSEUS study, subcutaneous DARA (DARA SC) + VRd (D-VRd) induction/consolidation (ind/consol) and D-R maintenance improved progression-free survival (PFS) and increased depth of response (complete response or better [≥CR] and MRD negativity [neg]) compared to VRd ind/consol and R maintenance for TE NDMM. Here, we report further results on deepening of response and MRD neg during maintenance. Methods: TE pts with NDMM were randomized 1:1 to D-VRd or VRd. Pts in both arms received up to six 28-day cycles (4 pre-ASCT ind, 2 post-ASCT consol) of VRd (V 1.3 mg/m 2 SC on Days [D] 1, 4, 8, 11; R 25 mg PO on D 1-21; d 40 mg PO/IV on D 1-4, 9-12) followed by R maintenance (10 mg PO on D 1-28 until progressive disease [PD]). Pts in the D-VRd arm also received DARA SC (DARA 1,800 mg + recombinant human hyaluronidase PH20 [rHuPH20; 2,000 U/mL; Halozyme]) QW in Cycles 1-2, Q2W in Cycles 3-6, and Q4W during maintenance until PD. MRD-neg rate (clonoSEQ) was defined as the proportion of ITT pts who achieved both ≥CR and MRD neg. Results: In the 709 pts randomized (D-VRd, n=355; VRd, n=354), responses deepened over time with D-VRd vs VRd, including rates of ≥CR (end of consol: 44.5% vs 34.7%; P= 0.0078 and overall: 87.9% vs 70.1%; P&lt;0.0001). MRD-neg rates increased over time and were higher with D-VRd vs VRd at 12, 24, and 36 mo after Cycle 1 Day 1 (all P&lt;0.0001; Table). Rates of sustained MRD neg for ≥12 mo were higher for D-VRd vs VRd (10 –5 : 64.8% vs 29.7%; P&lt;0.0001; 10 –6 : 47.3% vs 18.6%; P&lt;0.0001); results were consistent across prespecified clinically relevant subgroups. Among pts who were MRD positive (pos) at end of consol, significantly higher proportions of pts in the D-VRd group vs the VRd group achieved MRD neg during maintenance at 10 –5 (68.8% vs 52.7%; P= 0.0330) and 10 –6 (62.3% vs 31.0%; P&lt;0.0001) and sustained MRD neg for ≥12 mo at 10 –5 (44.2% vs 22.6%; P= 0.0028) and 10 –6 (34.4% vs 12.7%; P&lt;0.0001). End of consol and overall MRD neg at both 10 –5 and 10 –6 were associated with improved PFS. Additional data on response rates in different study phases and sustained MRD neg will be presented. Conclusions: During maintenance, a greater proportion of pts with MRD-pos status achieved MRD neg with D-R vs R. The higher rates of deep (10 –6 ) and sustained MRD neg achieved with D-VRd ind/consol and D-R maintenance vs VRd ind/consol and R maintenance translated to a clinically meaningful benefit of improved PFS. These data further support D-VRd and D-R maintenance as a new standard of care for TE pts with NDMM and highlight the benefit of DARA SC in maintenance. Clinical trial information: NCT03710603 . [Table: see text]

Daratumumab (DARA) + bortezomib/lenalidomide/dexamethasone (VRd) in transplant-eligible (TE) patients (pts) with newly diagnosed multiple myeloma (NDMM): Analysis of minimal residual disease (MRD) in the PERSEUS trial.