Evaluation of the safety, efficacy, and mechanism of action of obexelimab for the treatment of patients with IgG4-related disease: an open-label, single-arm, single centre, phase 2 pilot trial

Obexelimab, a non-cytolytic monoclonal antibody, was evaluated in a phase 2 pilot trial for patients with active IgG4-related disease. The study, conducted at Massachusetts General Hospital, included 15 patients aged 18-80 with confirmed IgG4-related disease. Patients received 5 mg/kg of obexelimab intravenously every 2 weeks for 24 weeks. The primary endpoint was the proportion of patients with a decrease of 2 or more from baseline in the IgG4-related disease responder index at day 169. 80% of patients achieved this primary endpoint, and 93% were designated as responders overall. Adverse events were reported in 87% of patients, with one case resulting in treatment discontinuation due to an infusion reaction. The findings suggest that obexelimab could be a promising treatment option for IgG4-related disease.