Daratumumab, Bortezomib, Dexamethasone (D-Vd) Versus Bortezomib And Dexamethasone (Vd) In Relapsed Or Refractory (Rr) Multiple Myeloma (Mm): Pooled Subgroup Analysis Of Lepus And Castor

Introduction: Daratumumab is a human IgGκ monoclonal antibody targeting CD38 with a direct on-tumor and immunomodulatory mechanism of action. In phase 3 clinical studies, the addition of daratumumab to standard-of-care regimens consistently demonstrated a significant progression-free survival (PFS) benefit and improved depth of response, including minimal residual disease-negativity, in patients (pts) with newly diagnosed MM or RRMM. In the primary analysis of the phase 3 CASTOR study (median follow-up: 7.4 mo), D-Vd reduced the risk of disease progression or death by 61% (median PFS, not reached [NR] vs 7.2 mo; hazard ratio [HR], 0.39; 95% confidence interval [CI], 0.28-0.53; P<0.001) and induced higher rates of deeper responses vs Vd in global pts with RRMM who received ≥1 prior line of therapy (Palumbo A, et al. N Engl J Med. 2016;375[8]:754-766). More recently, a similar clinical benefit of D-Vd was demonstrated in Chinese pts with RRMM who received ≥1 prior line of therapy in the phase 3 LEPUS study (Huang X, et al. EHA 2020. EP988). At a pre-specified interim analysis (median follow-up: 8.2 mo), D-Vd reduced the risk of disease progression or death by 72% (median PFS, NR vs 6.3 mo; HR, 0.28; 95% CI, 0.17-0.47; P<0.00001) and induced higher rates of deeper responses vs Vd. Here, we report the results of a pooled subgroups analysis, including Chinese pts in LEPUS and global pts in CASTOR, examining the efficacy of D-Vd vs Vd based on age, cytogenetic risk status, and renal function, at a median follow-up of 7.5 months.