Targeted interferon therapy with modakafusp alfa for relapsed or refractory multiple myeloma

• Modakafusp alfa delivers interferon alpha signalling to CD38+ myeloma and immune cells leading to myeloma cell death and immune activation

• Modakafusp alfa has a 43% single-agent response rate in RRMM at our recommended phase 2 doses, with primarily hematologic adverse events

Interferon-alpha has activity against multiple myeloma. Modakafusp alfa is an immunocytokine comprising two attenuated interferon-alpha2b molecules and an anti-CD38 IgG4 antibody, targeting delivery of interferon-alpha to CD38+ immune and myeloma cells. This phase I/II trial (NCT03215030) enrolled patients with relapsed/refractory multiple myeloma with ≥3 prior lines of treatment and refractory to or intolerant of ≥1 proteasome inhibitor and ≥1 immunomodulatory drug. During dose escalation, modakafusp alfa was administered at ten doses in four schedules across 13 cohorts. The primary endpoint was safety for dose escalation, and overall response rate for dose expansion. We enrolled 106 patients who had received a median of 6.5 lines of prior therapy; 84% of patients had myeloma previously refractory to an anti-CD38 antibody. The most feasible dosing schedule was every 4 weeks (Q4W), at which the maximum tolerated dose was 3 mg/kg. Among 30 patients treated at 1.5 mg/kg Q4W, the overall response rate was 43.3%, with a median duration of response of 15.1 months (95% CI, 7.1-26.1); median progression-free survival was 5.7 months (95% CI, 1.2-14.0). Grade ≥3 adverse events occurred in 28 (93.3%) patients, the most common were neutropenia (66.7%) and thrombocytopenia (46.7%); infections were reported in 8 (26.7%) patients (including grade 3 in 4 [16.7%]). Modakafusp alfa therapy induced upregulation of the type I interferon gene signature score, increased CD38 receptor density in CD38+ cells, and innate and adaptive immune cell activation. Modakafusp alfa resulted in anti-tumor activity and immune activation in patients with multiple myeloma. Adverse events were primarily hematologic.