Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune inflammatory disorder of the central nervous system associated with blindness and debilitating chronic pain. It primarily affects eye nerves and the spinal cord and pain can be felt throughout various parts of the body including the legs and arms. “With NMOSD, 86% of patients can be affected by pain, which can negatively impact their quality of life (QOL),” says Kristina Patterson, MD, PhD. “Given this prevalence, it is important to understand how treatment with [inebilizumab] can affect pain among patients.”
Analyzing Pain Outcomes
For research presented at the 2022 American Academy of Neurology (AAN) Annual Meeting, Dr. Patterson and colleagues presented results of a further examination of the N-MOmentum study, a double-blind, placebo-controlled, randomized phase II/III trial that assessed the efficacy and safety of inebilizumab in adults diagnosed with NMOSD. Dr. Patterson and colleagues analyzed the pain experienced by all study participants in the intention-to-treat (ITT) population with a minimum of three pain assessments during the randomized controlled period (RCP). “This analysis aimed to understand the long-term impact of treatment with [inebilizumab] on the pain and quality of life among participants in the phase III study,” specified Dr. Patterson.
Dr. Patterson and team measured the pain, disability, and QOL of study participants using the 36-item Short-Form Health Survey Body Pain Subscores (SF36-BPS), which has a 0-100 range scale with lower numbers indicating more severe pain; the neuromyelitis optica spectrum disorder 11-point numeric rating scale, which has a 0-10 range scale with higher numbers indicating more severe pain; the Expanded Disability Status Scale (EDSS) to classify disability with 0 indicating no disability and 10 indicating death; and the SF36-Physical Component Summary (PCS), which was used to gauge QOL.
Pain Score & QOL Improvements
Of the participants in the N-MOmentum study, 213 were included in the pain analyses (inebilizumab, N = 161; placebo, N = 52). At the start of the observation, there were no differences in pain scores between the groups. However, among those with a baseline SF36-BPS less than 40 who received inebilizumab, the investigators reported year-on-year improvements from baseline in mean scores of 6.57 points at 1 year, 7.08 at 2 years, and 7.96 at 3 years. After 3 years, Dr. Patterson and colleagues determined that patients treated with inebilizumab had fewer SF36-BPS scores of less than 40 when compared with those treated with placebo (17.6% vs 30.1%), improvements in general health were moderate, and EDSS scores showed improvement. Participants with greater baseline disability showed modest improvement in the PCS domains.
When asked what she hopes the study would convey to physicians, Dr. Patterson said, “It is most important for physicians to understand that fewer participants experienced moderate or severe pain after long-term treatment with [inebilizumab].”