Subcutaneous delivery of daratumumab in Japanese patients with relapsed/refractory multiple myeloma.

Subcutaneous daratumumab (DARA SC; daratumumab co-formulated with recombinant human hyaluronidase PH20) is administered in ~ 5 min and demonstrates safety and efficacy comparable to intravenous daratumumab, with low infusion-related reaction (IRR) rates in global populations. This open-label, multicenter, phase 1 study is the first evaluation of DARA SC in Japanese patients. Eligible patients had relapsed/refractory multiple myeloma (RRMM; ≥ 2 prior lines of therapy including a proteasome inhibitor and immunomodulatory drug). Patients (N = 6) received DARA SC 1,800 mg until progression (weekly for Cycles 1-2; every 2 weeks for Cycles 3-7; monthly for Cycles 7 + [28-day cycles]). The primary objective was to evaluate safety. Secondary objectives included efficacy and pharmacokinetics. Median time of administration was 3-4 min for all injections. No dose-limiting toxicity occurred, and no treatment-emergent adverse events were serious or led to discontinuation. No IRRs were observed; 4 (67%) patients had injection-site reactions (all grade 1). Overall response rate was 67%. Pharmacokinetics of DARA SC in Japanese patients were similar to findings from the global phase 1b PAVO study (NCT02519452). DARA SC at a flat dose of 1,800 mg was well tolerated in Japanese RRMM patients with comparable efficacy and pharmacokinetics to intravenous daratumumab. ClinicalTrials.gov identifier NCT03242889.