MM-235: Outcomes of Daratumumab, Pomalidomide, and Dexamethasone (DPd) Followed by High-Dose Chemotherapy and Autologous Stem Cell Transplantation (HDCT/ASCT) in Patients with Relapsed/Refractory Multiple Myeloma (RRMM)

Abstract

<h3>Context:</h3> At this time, there is no rationale to favor a specific therapeutic class (e.g., immunomodulatory agents (IMiD), proteasome inhibitors (PI), or monoclonal antibody) over another for the treatment of relapsed/refractory myeloma (RRMM). Our institute treated a series of patients with induction therapy consisting of daratumumab, pomalidomide, and dexamethasone (DPd) followed by high-dose chemotherapy and autologous stem cell transplantation (HDCT/ASCT) in patients with RRMM. <h3>Objective:</h3> To present longer-term efficacy and safety outcomes with DPd followed by HDCT/ASCT in patients with RRMM. <h3>Methods:</h3> We treated 18 patients with RRMM at the University of Kansas Health System between May 2016 and April 2020 with DPd as induction therapy followed by HDCT/ASCT. DPd was administered as daratumumab 16 mg/kg weekly for cycles 1 and 2, every 2 weeks for cycles 3–6, and then every 4 weeks; pomalidomide was dosed at 4 mg orally on days 1–21 of a 28-day cycle; and dexamethasone 20 or 40 mg weekly. Responses were evaluated using the 2016 International Myeloma Working Group (IMWG) criteria. <h3>Results:</h3> Patients received a median of two lines (1–4). Out of the 18 patients, 72% received ASCT in the past prior to this treatment. In addition, 78%, 78%, and 72% were refractory to PI and IMiDs and double refractory to IMiDs and PI, respectively. The median time from diagnosis to treatment was 12 months. The median number of DPd cycles received was 4 (2–7) cycles. A median follow-up of 27 months (range: 12–39), the overall response rate (ORR) after induction treatment with DPd was 100%. ORR on day 100-post ASCT was 100%, 67% achieved ≥CR, and 78% achieved ≥VGPR. There was no treatment-related mortality on day 100. Median progression-free survival was 34 months (95%, CI=NA); median overall survival was not reached. The most common grade ≥3 adverse events were thrombocytopenia (53%), anemia (40%), neutropenia (53%). <h3>Conclusions:</h3> DPd as induction therapy followed by HDCT/ASCT demonstrated deep, durable, and clinically meaningful responses with a manageable safety profile in patients with RRMM.