Subcutaneous Daratumumab with Rapid Corticosteroid Tapering in Relapsed or Refractory Multiple Myeloma Patients: Part 3 Update of the Open-Label, Multicenter, Phase 1b Pavo Study

Introduction: Daratumumab (DARA) is a human monoclonal IgGκ monoclonal antibody targeting CD38 with a direct on-tumor and immunomodulatory mechanism of action. DARA is approved as monotherapy or in combination with standard-of-care regimens for the treatment of relapsed or refractory multiple myeloma (RRMM). The phase 1b 3-part PAVO study investigated subcutaneous delivery of DARA (DARA SC) in patients (pts) with RRMM. Part 1 demonstrated that a mix-and-deliver formula of DARA with recombinant human hyaluronidase PH20 (rHuPH20; ENHANZE ® drug delivery technology Halozyme, Inc.) was safe and effective (Usmani SZ, et al. Blood. 2019). In Part 2, a co-formulated DARA SC (DARA 1,800 mg + rHuPH20 30,000 U, in 15 mL) produced similar trough concentrations (C trough) to intravenous DARA (DARA IV) with no new safety concerns (San-Miguel J, et al. Haematologica. 2021). Here, we present the results from Part 3 of the PAVO study, which investigated the safety of pre- and post-dose corticosteroid tapering during DARA SC administration.