A phase 1 study of lucatumumab, a fully human anti-CD40 antagonist monoclonal antibody administered intravenously to patients with relapsed or refractory multiple myeloma

In this open-label, multicentre, phase 1 study a fully human anti-CD40 antagonist monoclonal antibody, lucatumumab, was evaluated in patients with relapsed/refractory multiple myeloma (MM). The primary objective was to determine the maximum tolerated dose (MTD) based on dose-limiting toxicities (DLTs). Secondary objectives included safety, pharmacokinetics, pharmacodynamics and antimyeloma activity. Twenty-eight patients, enrolled using a standard 3+3 dose escalation, received one or two (n=3) cycles of lucatumumab 1.0, 3.0, 4.5 or 6.0mg/kg once weekly for 4weeks. Common lucatumumab-related adverse events were reversible, mild-to-moderate infusion reactions. Severe adverse events were anaemia, chills, hypercalcaemia and pyrexia (7% each). DLTs included grade 4 thrombocytopenia, grade 3 increased alanine aminotransferase and grade 4 increased lipase (n=1 each). The MTD was 4.5mg/kg. At doses =3.0mg/kg, sustained receptor occupancy (=87%), observed throughout weekly infusions up to 5weeks after the last infusion, correlated with an estimated half-life of 419d. Twelve patients (43%) had stable disease, and one patient (4%) maintained a partial response for =8months. These findings indicate that single-agent lucatumumab was well tolerated up to 4.5mg/kg with modest clinical activity in relapsed/refractory MM, warranting further study as a combination therapy.