Daratumumab, Bortezomib, and Dexamethasone Versus Bortezomib and Dexamethasone in Chinese Patients with Relapsed or Refractory Multiple Myeloma: Phase 3 LEPUS (MMY3009) Study

BackgroundDaratumumab plus bortezomib/dexamethasone (D-Vd) significantly improved outcomes versus Vd in patients with relapsed or refractory multiple myeloma (RRMM) in the phase 3 CASTOR study. We report the results of a prespecified interim analysis of the phase 3 LEPUS study of D-Vd versus Vd in Chinese patients with RRMM.Patients and MethodsChinese patients with ≥ 1 prior line of therapy were randomized 2:1 to receive 8 cycles (21 days/cycle) of bortezomib (1.3 mg/m2 subcutaneously) and dexamethasone (20 mg orally/intravenously) ± daratumumab (16 mg/kg intravenously). The primary endpoint was progression-free survival (PFS).ResultsA total of 211 patients were randomized (D-Vd, 141; Vd, 70). After an 8.2-month median follow-up, D-Vd significantly prolonged PFS versus Vd (median, not reached vs. 6.3 months; hazard ratio, 0.28; 95% confidence interval, 0.17-0.47; P < .00001) and significantly improved the rates of overall response (83% vs. 65%; P = .00527), ≥ very good partial response (65% vs. 33%; P = .00002), ≥ complete response (33% vs. 11%; P = .00079), and minimal residual disease negativity (10–5 sensitivity; 22% vs. 3%; P = .0002). The PFS benefit of D-Vd versus Vd was maintained across prespecified subgroups, including patients with prior bortezomib treatment and with high-risk cytogenetics. Thrombocytopenia (D-Vd, 51%; Vd, 37%), lymphopenia (44%; 29%), and lung infection (30%; 22%) were the 3 most common grade 3/4 treatment-emergent adverse events. Although patients in both treatment groups experienced higher rates of grade 3/4 lymphopenia and infections versus patients in CASTOR, the safety profile was generally consistent with that of CASTOR.ConclusionThese data support the use of D-Vd in Chinese patients with RRMM.