Long-term efficacy data: inebilizumab for NMOSD

Inebilizumab demonstrated favourable long-term safety and efficacy outcomes for patients with neuromyelitis optica spectrum disorder (NMOSD). Results showed that the risk of attack in NMOSD participants treated with inebilizumab remained low. Moreover, long-term use of inebilizumab did not result in the occurrence of unexpected serious adverse events [1].

Inebilizumab is a humanised anti-CD19 monoclonal antibody depleting B cells, that is approved in the USA for the treatment of NMOSD patients who are seropositive for immunoglobulin G autoantibodies against aquaporin-4 (AQP4-IgG+) [2]. Prof. Bruce Cree (UCSF Multiple Sclerosis Center, CA, USA) presented the final efficacy and safety data of the 5.5-year follow-up, open-label extension (OLE) period of the randomised-controlled, phase 2/3 N-MOmentum trial (NCT02200770).

NMOSD AQP4+ patients (n=230) were randomised 3:1 to inebilizumab (300 mg, intravenous, administered at day 1 and 15) or placebo. After 6 months, patients could enter the OLE period, during which all enrolled participants received inebilizumab every 6 months. In total, 174 patients completed the OLE period. The primary outcome was the time to the first attack.

The results of the randomised-controlled period showed that inebilizumab outperformed placebo: 87.0% of the patients on inebilizumab were attack-free, compared with 59.9% of the placebo receivers (risk reduction 72.8%; P<0.001) [1,3]. After completion of the OLE period, 87.7% of the patients continuing inebilizumab, and 83.4% of patients switching from placebo, were attack-free. The mean treatment duration was 3.2 years, with a reported annualised attack rate of 0.092. Treatment-emergent adverse events (AE) occurred in 39.6% of the patients. Urinary tract infections (26.2%), nasopharyngitis (20.9%), and arthralgia (17.3%) were the most frequently reported AEs. The rate of infections did not increase with continued treatment (116.3 per 100 person-years in year 1 vs 55.1 in year 4). Transient low IgG levels (<700 mg/dL) were reported in 105 subjects. However, no association between IgG levels and the occurrence of infections was observed. One patient died from complications of an NMOSD attack after 9 days of inebilizumab treatment. Two other patients died after 224 and 1,225 days of inebilizumab therapy, due to a CNS event of unclear aetiology and following a SARS-CoV-2 infection, respectively.

1. Cree BAC, et al. Safety and efficacy of inebilizumab in NMOSD over a mean duration of 3.2 years: end of study data from the N-Momentum trial. P037, ECTRIMS 2021 Virtual Congress, 13–15 October.
2. Frampton JE. Drugs. 2020;80(12):1259–1264.
3. Cree B, et al. Lancet 2019;394(10206):1352–1363.

 

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Posted on 9 December, 20219 December, 2021