Abstract
Abstract only
LBA8512
Background: DARA, a human anti-CD38 IgG1κ mAb, has single agent activity and is well-tolerated in rel/ref MM (Lokhorst HM et al. ASCO 2014). This ongoing phase 2 study (NCT01985126) evaluated DARA monotherapy in the FDA breakthrough therapy designation population: MM patients with ≥ 3 prior lines of therapy including a proteasome inhibitor (PI) and an immunomodulatory agent (IMiD), or double refractory to a PI and IMiD. Preliminary results are reported. Methods: MMY2002 is a 2-part, open-label, international, multicenter study. In part 1 stage 1, 34 patients were randomized to DARA 8 mg/kg (n = 18) q4w or 16 mg/kg (n = 16) qw x 8 wk, q2w x 16 wk, then q4w in a Simon-2-stage design to determine the most effective dose. Subsequently, 90 additional patients were enrolled in the 16 mg/kg DARA group. The primary endpoint was overall response rate (ORR) by independent review (IRC). Results: Data for the 16 mg/kg DARA group are presented (n = 106). Baseline characteristics: median time since diagnosis, 4.8 y; median prior treatment lines, 5; 75% ISS ≥ 2. Refractory to: last line of therapy, 96%; last PI and IMiD, 95%; pomalidomide, 63%: carfilzomib, 48%; alkylating agents, 78%. Adverse events (AE; ≥ 20%) were fatigue (39.6%), anemia (33.0%), nausea (29.2%), thrombocytopenia (25.5%), back pain (22.6%), neutropenia (22.6%), cough (20.8%). Infusion-related reactions (IRR, 42.5%) were mainly grade 1/2 during first infusion (grade 3 4.7%; no grade 4). No patients discontinued study due to IRRs; 5 (4.7%) discontinued treatment due to AEs. None of these AEs were assessed by the investigator to be DARA-related. ORR (IRC assessed) was 29.2%, with 3 sCR, 10 VGPR, and 18 PR with a 7.4 month median duration of response. ORR was consistent across clinically relevant subgroups. Median time to progression was 3.7 months. Median overall survival has not been reached and the estimated 1-year OS rate is 65%. After a median follow up of 9.4 months 14/31 (45.2%) of responders remain on therapy. Conclusions: In a heavily pre-treated MM population (95% refractory to last PI and IMiD), DARA at 16 mg/kg showed meaningful durable single agent activity, with deep responses and a favorable safety profile. Clinical trial information: NCT01985126.