A post hoc analysis of results from N-MOmentum, a double-blind, phase II/III trial, demonstrates that inebilizumab is safe and effective in Black patients with neuromyelitis optica spectrum disorder (NMOSD), according to findings presented at the ACTRIMS 2022 Forum.
“[NMOSD] has a higher prevalence, earlier age of onset, and higher levels of disability over time in [Black patients] than in White,” wrote Evanthia Bernitsas, MD, and colleagues. “Inebilizumab is an anti-CD19, B-cell depleting monoclonal antibody, FDA-approved for the treatment of NMOSD in adults who are seropositive for aquaporin-4 immunoglobulin (Ig) G autoantibodies.”
The study team aimed to examine the safety, efficacy, and pharmacokinetics of inebilizumab among individuals with NMOSD who self-reported as Black and to describe disease management in this group of at-risk patients. N-MOmentum involved a 28-week randomized controlled period, in which IV inebilizumab 300 mg or placebo was administered on days 1 and 15, and an open-label period of 2 or more years. The researchers performed post hoc analyses for Black participants. Time to first NMOSD attack served as the primary endpoint; other endpoints included Expanded Disability Status Scale (EDSS) worsening, B-cell and serum Ig levels, the incidence of adverse events, and pharmacokinetics profile analyses.
No EDSS Worsening & Low Infection Rates With Inebilizumab
Among 231 participants randomly assigned in N-MOmentum, 20 self-reported as Black, among whom 15 were randomly assigned to inebilizumab and five to placebo. In the randomized controlled period, Black patients being treated with inebilizumab were less likely to experience an attack compared with Black patients in the placebo group (HR, 0.331; 95% CI, 0.02-5.31) and the total placebo group (HR, 0.133; 95% CI, 0.02-0.99).
In total, 19 Black patients had any exposure to inebilizumab in either the randomized controlled period or the open-label period (total, 61.7 person-years). The annualized attack rate in this group was 0.06 (95% CI, 0.02-0.22), compared with 0.09 (95% CI, 0.07-0.13) in the total group treated with inebilizumab (total, 730.4 person-years). There was no worsening of EDSS among Black patients treated with inebilizumab in the randomized controlled period, compared with 1/5 Black patients receiving placebo (20%). Inebilizumab induced rapid, sustained B-cell depletion comparable to that seen in the overall population, but it yielded serum IgG concentrations of less than 300 mg/dL in only 1 of 19 Black patients with any inebilizumab exposure (5.3%). Pharmacokinetics among Black patients were comparable to those of non-Black individuals.
Among patients treated during the randomized controlled period, more than one-half of Black patients (10/15; 66.7%) experienced at least one treatment-emergent adverse event compared with four out of five Black patients receiving placebo (80.0%). Infections were the most frequent adverse event of special interest with treatment, but rates were low; proportionally fewer participants treated with inebilizumab (4/15; 26.7%) had infections in the randomized controlled period compared with those being treated with placebo (3/5; 60.0%). No deaths were reported in either group.
“These data support the efficacy and safety of inebilizumab in [Black patients] with NMOSD and indicate a [pharmacokinetic] profile comparable to [non-Black] participants,” Dr. Bernitsas and colleagues wrote. “Evaluation of larger populations is needed to confirm these results.”