Objective:

This study aimed to evaluate the safety and treatment adherence of inebilizumab in patients with neuromyelitis optica spectrum disorder (NMOSD).

Background:

Inebilizumab is an anti-CD19 monoclonal antibody that selectively and efficiently depletes B cells. However, real-world data in Chinese populations remain limited.

Design/Methods:

We conducted a single-center retrospective cohort study at West China Hospital, Sichuan University, consecutively enrolling NMOSD patients treated with inebilizumab. Primary outcomes were treatment adherence and annualized relapse rate (ARR). Safety outcomes included infusion-related reactions (IRRs), infections graded per CTCAE v5.0, and adverse events; laboratory outcomes included neutrophil count decrease and hypoalbuminemia.

Results:

A total of 125 patients (87.2% female; median age 45.68, IQR 34.84–56.83) received inebilizumab, with a median treatment duration of 1.33 years (IQR 0.77–1.88). 116 (92.8%) maintained treatment, while 9 (7.2%) discontinued: 5 due to relapse, 1 due to poor adherence, 2 for financial reasons, and 1 because infusions in the provincial capital were inconvenient. Median ARR decreased significantly from 0.97 (IQR 0.53–2.99) before treatment to 0 (IQR 0.00–0.00) on treatment (p<0.001). Sixteen (12.8%) patients experienced 21 relapses; 11 (68.8%) occurred within the first year, and 9 (56.3%) were mild. IRRs were reported in 3/125 (2.4%). During treatment, 12/125 (9.6%) patients developed infections; 83.3% (10/12) were grade 1–2 (CTCAE v5.0). Only two (2%) patients required hospitalization for pneumonia and urinary tract infection; one recovered after antibiotics (grade 3), and one died due to severe pneumonia and viral encephalitis (grade 5). Additionally, 7.4% (6/81) had decreased neutrophil counts and 7.4% (6/81) had hypoalbuminemia.

Conclusions:

In this Chinese single-center real-world cohort, intravenous inebilizumab substantially reduced relapse burden with an overall acceptable safety profile. Ongoing monitoring of infection risk and neutrophil levels and longer follow-up are warranted to further validate benefits and safety.