To evaluate the infusion experience with inebilizumab for participants enrolled in a clinical trial for neuromyelitis optica spectrum disorder (NMOSD).

N-MOmentum is a randomized, placebo-controlled, double-blind, phase 2/3 trial assessing the efficacy and safety of inebilizumab, an anti-CD19 B-cell depleting monoclonal antibody, in patients with NMOSD. Infusion-related reactions occur commonly in patients treated with B-cell depleting monoclonal antibodies. This can lead to interruptions in infusions and corresponding lengthening of infusion times. Infusion reactions and associated infusion time during the randomized controlled phase (RCP) and open-label extension (OLE) of N-MOmentum were analyzed.

230 patients were dosed during the N-MOmentum study; the dosing regimen consisted of 300mg on day 1 and day 15 at the initiation of treatment and 300mg every 6 months thereafter. The infusion duration of 90 minutes was protocol determined.  Patients received pre-infusion treatment with intravenous methylprednisolone (100 mg or equivalent corticosteroid), oral diphenhydramine (25-50 mg or equivalent antihistamine), and oral acetaminophen/paracetamol. Infusion duration and infusion-related reactions were assessed throughout the study.

Infusion-related reactions occurred in 6 placebo subjects (10.7%) and 16 inebilizumab subjects (9.2%) during the RCP and 27 subjects (12.0%) during the OLE (all on inebilizumab). The most common infusion-related reactions throughout the OLE were headache (2.7%), nausea (2.2%), and somnolence (1.8%); all were grade 1 or 2. Out of 1,716 inebilizumab doses given throughout the OLE (at the time of analysis), 99.5% were completed (entire dose was given). Of the complete doses given, the mean infusion time was 93.4 minutes.