Safety and efficacy of daratumumab in combination with bortezomib and dexamethasone in Japanese patients with relapsed or refractory multiple myeloma.

Daratumumab in combination with bortezomib and dexamethasone (DVd) has demonstrated longer progression-free survival than combination of bortezomib and dexamethasone in patients with relapsed or refractory multiple myeloma (RRMM). In this multicenter, open-label, phase-1 study, the safety, efficacy, and pharmacokinetics (PK) of DVd were evaluated in Japanese patients with RRMM. Eight patients with RRMM aged between 54 and 82 years were enrolled and treated with DVd regimen. Primary endpoints were tolerability and safety. Secondary endpoints were overall response rate (ORR), very good partial response (VGPR) or better, complete response (CR) or better, time to response (TTR), PK, and immunogenicity. All patients (n = 8) experienced Grade ≥ 3 treatment-emergent adverse events (TEAE), with thrombocytopenia (n = 6, 75%) being the most frequent. Mild Grade ≤ 2 infusion-related reactions were reported in five patients. Serious TEAEs were herpes zoster, nasopharyngitis, and prostate cancer (n = 1 each). Three dose-limiting toxicities were observed in two patients. No death or disease progression was reported as of the study cut-off date. ORR was 100% (2 CRs or better, 2 VGPRs, 4 PRs). The median TTR was 0.9 months. PK profiles were comparable to previous studies. The DVd regimen showed acceptable safety with favorable efficacy in Japanese patients with RRMM. CLINICAL TRIAL REGISTRATION NUMBER: NCT02497378.