Inebilizumab improves pain outcomes and quality of life in neuromyelitis optica spectrum disorder

Objective: To assess the impact of long‐term inebilizumab, an anti‐CD19 B‐cell depleting antibody, on pain and quality of life (QoL) in patients with neuromyelitis optica spectrum disorder (NMOSD). Background: Pain is a common, debilitating symptom of NMOSD that has a detrimental impact on the QoL of patients. Correlations were previously reported between 11‐point Pain Numeric Rating Scale (NRS‐11) scores and 36‐Item Short‐Form Survey Body Pain Sub scores (SF36‐BPS) in the N‐MOmentum study (NCT02200770), in which inebilizumab significantly improved SF36‐BPS after first dose in participants with moderate‐to‐severe pain (SF36‐BPS <40) at baseline (Kim et al., 2021). Methods: N‐MOmentum was a double‐blind trial in 230 participants, randomized 3:1 to inebilizumab 300mg: placebo with an open‐label extension period of ≥2 years. Pain, QoL, and disability were measured using the SF36‐BPS, SF36‐Physical Component Score (PCS), and Expanded Disability Status Scale (EDSS), respectively (Cree et al., 2019). Results: 213 participants were included in the pain analyses (inebilizumab, n = 161; placebo, n = 52). At baseline, there were no differences in pain scores between the two treatment groups (Kim et al., 2021). NRS pain scores increased modestly during NMOSD attacks in the five areas assessed: arm, eye, legs, lower back, and upper back. Among participants with reduced QoL at baseline, 62/92 (75%) reported moderate or severe pain (NRS ≥4) in at least one of five body areas, compared with 32/125 (26%) for those with normal QoL at baseline. A strong correlation was observed between NRS scores and SF‐36 pain inventory scores in participants with average pain (Spearman R = −0.67, p < 0.0001) and/or worst pain (Spearman R = −0.66, p < 0.0001). At baseline, participants with reduced QoL had higher levels of disability. A strong correlation was found between the EDSS score and SF‐36‐PCS (Spearman R = −0.63, p < 0.0001). The proportion of participants reporting moderate or severe pain was reduced over time with inebilizumab treatment. The proportion of participants with severe pain reduced from 61% before treatment to 26% after 3.5–4.5 years (6–7 doses of inebilizumab). After three years of treatment with inebilizumab, proportionally fewer participants had an SF‐36 score of <40 in ‘Role physical,’ ‘Bodily pain,’ ‘General health,’ and PCS domains than before treatment Conclusions: Long‐term inebilizumab treatment over three years was associated with improved pain outcomes in patients with NMOSD. Correlations between measures of pain, QoL, and disability suggest all may be valid metrics of disease status and treatment effects in NMOSD.