MM-350: Daratumumab (DARA) + Lenalidomide/Bortezomib/Dexamethasone (RVd) in African American/Black Patients (Pts) with Transplant-Eligible Newly Diagnosed Multiple Myeloma (NDMM): Subgroup Analysis of GRIFFIN

Context: To optimize treatment of Black pts with multiple myeloma, a greater understanding of differences in outcomes in Black pts vs. White pts is needed. In GRIFFIN, DARA plus RVd (D-RVd) improved rates and depth of response in autologous stem cell transplant (ASCT)-eligible NDMM pts. Here, we report a subgroup analysis of Black pts from GRIFFIN. Design: Between 2016 and 2018, pts in the United States were randomized 1:1 to RVd ± DARA and received 4 induction cycles, high-dose therapy, ASCT, 2 consolidation cycles, and maintenance with R ± DARA for 24 mo. The pre-specified primary endpoint was stringent complete response (sCR) rate by end of consolidation, which occurred at a median follow-up of 13.5 mo. Results below are based on longer follow-up (22.1 mo). Results: Two hundred seven pts (D-RVd, n=104; RVd, n=103) were randomized; 32 (15%) pts were Black (D-RVd, n=14; RVd, n=18), and 161 (78%) pts were White (D-RVd, n=85; RVd, n=76). Baseline demographics were generally similar between treatment arms in Black and White pts. D-RVd vs RVd improved the sCR rate by end of consolidation in Black (10 [71%]; 6 [33%]) and White pts (35 [43%]; 24 [34%]). Including post-consolidation data, sCR with D-RVd vs. RVd was achieved by 12 (86%) and 7 (39%) Black pts and 50 (61%) and 33 (46%) White pts. ORR by end of consolidation was improved for D-RVd vs. RVd in Black pts (14 [100%] vs. 17 [94%]), as were rates of ≥CR (12 [86%] vs. 7 [39%]) and minimal residual disease at 10−5 (5 [36%] vs. 3 [17%]). Grade 3/4 TEAEs (≥25%) with D-RVd/RVd included neutropenia (Black pts, 50%/22%; White pts, 41%/16%), lymphopenia (29%/39%; 23%/16%), and thrombocytopenia (29%/11%; 14%/8%). Grade 3/4 infections for D-RVd/RVd occurred in 36%/17% of Black and 20%/23% of White pts. IRRs occurred in 29% of Black and 45% of White pts. Conclusions: GRIFFIN demonstrated that D-RVd improved responses in the Black NDMM pt subgroup, but larger studies are needed to better define the magnitude of DARA benefit in Black pts. Improved recruitment of Black pts in clinical trials is needed to understand disease biology and response to therapy among racial groups.