A phase 2 randomized study of modakafusp alfa as a single agent for patients with relapsed/refractory multiple myeloma

ABSTRACT: Modakafusp alfa is a first-in-class immunocytokine-directing interferon alfa to CD38+ cells. Our previous phase 1/2 trial identified 2 potential phase 2 doses of modakafusp alfa for patients with relapsed/refractory multiple myeloma (RRMM): 1.5 or 3 mg/kg every 4 weeks. The overall response rate (ORR) among 30 patients treated at 1.5 mg/kg was 43%. This phase 2 dose optimization study randomized 147 patients with triple-class refractory disease and ≥3 previous lines of therapy 1:1 to modakafusp alfa 120 mg (n = 71) or 240 mg (n = 75) every 4 weeks (fixed-dose equivalents of 1.5 and 3 mg/kg every 4 weeks). Patients had received a median of 6 previous lines of therapy; 66% were penta-exposed and 45% had previously been exposed to anti-B-cell maturation antigen (BCMA) therapy. Modakafusp alfa development was discontinued for strategic reasons by the sponsor and the study was terminated early. At median follow-up of 7.3 and 7.6 months in the 120- and 240-mg arms, ORRs were 32% and 41%, and median progression-free survival was 4.1 and 5.3 months, respectively. ORRs were higher in patients who had not received previous BCMA therapy (46% vs 29%). The most common treatment-related adverse events (TEAEs) in the 120- and 240-mg arms were thrombocytopenia (75% and 84%; grade ≥3, 55% and 61%; respectively) and neutropenia (68% and 73%; grade ≥3, 56% and 68%; respectively); 90% and 96% of patients, respectively, experienced grade ≥3 TEAEs; 39% and 44%, respectively, experienced serious TEAEs. Our results confirm the efficacy of single-agent modakafusp alfa for patients with RRMM. This trial was registered at www.clinicaltrials.gov as #NCT03215030.