This post hoc analysis of the randomized, placebo-controlled N-MOmentum study (NCT02200770) of inebilizumab in neuromyelitis optica spectrum disorder (NMOSD) evaluated relationships between circulating B-cell subsets and aquaporin-4 immunoglobulin G (AQP4-lgG) titers and attacks. Among participants receiving placebo, CD20+ and CD27+ B-cell counts were modestly increased from the pre-attack visit to attack; plasmablast/plasma cell gene signature was increased from baseline to the pre-attack visit (p = 0.016) and from baseline to attack (p = 0.009). With inebilizumab treatment, B-cell subset counts decreased and did not increase with attacks. No difference in change of AQP4-IgG titers from baseline to time of attack was observed.

OBJECTIVE: To investigate relationships between serum neurofilament light chain (sNfL), ubiquitin C-terminal hydrolase L1 (sUCHL1), tau (sTau) and glial fibrillary acidic protein (sGFAP) levels and disease activity/disability in neuromyelitis optica spectrum disorder (NMOSD), and the effects of inebilizumab on these biomarkers in N-MOmentum. METHODS: N-MOmentum randomised participants to receive inebilizumab or placebo with a randomised controlled period (RCP) of 28 weeks and an open-label follow-up period of ≥2 years. The sNfL, sUCHL1, sTau and sGFAP were measured using single-molecule arrays in 1260 scheduled and attack-related samples from N-MOmentum participants (immunoglobulin G (IgG) autoantibodies to aquaporin-4-positive, myelin oligodendrocyte glycoprotein-IgG-positive or double autoantibody-negative) and two control groups (healthy donors and patients with relapsing-remitting multiple sclerosis). RESULTS: The concentration of all four biomarkers increased during NMOSD attacks. At attack, sNfL had the strongest correlation with disability worsening during attacks (Spearman R2=0.40; p=0.01) and prediction of disability worsening after attacks (sNfL cut-off 32 pg/mL; area under the curve 0.71 (95% CI 0.51 to 0.89); p=0.02), but only sGFAP predicted upcoming attacks. At RCP end, fewer inebilizumab-treated than placebo-treated participants had sNfL>16 pg/mL (22% vs 45%; OR 0.36 (95% CI 0.17 to 0.76); p=0.004). CONCLUSIONS: Compared with sGFAP, sTau and sUCHL1, sNfL at attack was the strongest predictor of disability worsening at attack and follow-up, suggesting a role for identifying participants with NMOSD at risk of limited post-relapse recovery. Treatment with inebilizumab was associated with lower levels of sGFAP and sNfL than placebo. TRIAL REGISTRATION NUMBER: NCT02200770.

Inebilizumab, a humanized, glycoengineered, IgG1 monoclonal antibody that depletes CD19+ B-cells, is approved to treat aquaporin 4 (AQP4) IgG-seropositive neuromyelitis optica spectrum disorder (NMOSD). Inebilizumab is afucosylated and engineered for enhanced affinity to Fc receptor III-A (FCGR3A) receptors on natural killer cells to maximize antibody-dependent cellular cytotoxicity. Previously, the F allele polymorphism at amino acid 158 of the FCGR3A gene (F158) was shown to decrease IgG-binding affinity and reduce rituximab (anti-CD20) efficacy for NMOSD attack prevention. In contrast, our current findings from inebilizumab-treated NMOSD patients indicate similar clinical outcomes between those with F158 and V158 allele genotypes.

Background

In the N-MOmentum trial, the risk of an adjudicated neuromyelitis optica spectrum disorder (NMOSD) attack was significantly reduced with inebilizumab compared with placebo.

Objective

To demonstrate the robustness of this finding, using pre-specified sensitivity and subgroup analyses.

Methods

N-MOmentum is a prospective, randomized, placebo-controlled, double-masked trial of inebilizumab, an anti-CD19 monoclonal B-cell-depleting antibody, in patients with NMOSD. Pre-planned and post hoc analyses were performed to evaluate the primary endpoint across a range of attack definitions and demographic groups, as well as key secondary endpoints.

Results

In the N-MOmentum trial (ClinicalTrials.gov: NCT02200770), 174 participants received inebilizumab and 56 received placebo. Attack risk for inebilizumab versus placebo was consistently and significantly reduced, regardless of attack definition, type of attack, baseline disability, ethnicity, treatment history, or disease course (all with hazard ratios < 0.4 favoring inebilizumab, p < 0.05). Analyses of secondary endpoints showed similar trends.

Conclusion

N-MOmentum demonstrated that inebilizumab provides a robust reduction in the risk of NMOSD attacks regardless of attack evaluation method, attack type, patient demographics, or previous therapy.The N-MOmentum study is registered at ClinicalTrials.gov: NCT2200770.

Background

Inebilizumab is an anti-CD19 antibody approved for the treatment of neuromyelitis optica spectrum disorder (NMOSD) in adults with aquaporin-4 autoantibodies. The relationship between B-cell, plasma-cell (PC), and immunoglobulin depletion with longitudinal reductions in NMOSD activity after inebilizumab treatment was characterised post hoc in an exploratory analysis from the N-MOmentum study (NCT02200770).

Methods

Peripheral blood CD20+ B cells, PC gene signature, and immunoglobulin levels were assessed throughout N-MOmentum (follow-up ≥2.5 years); correlations with clinical metrics and magnetic resonance imaging (MRI) lesion activity were assessed.

Findings

Inebilizumab induced durable B-cell and PC depletion within 1 week versus placebo. Although no association was observed between B-cell counts at time of attack and NMOSD activity, depth of B-cell depletion after the first dosing period correlated with clinical outcomes. All participants receiving inebilizumab demonstrated a robust long-term therapeutic response, and participants with ≤4 cells/μL after the first 6-month dosing interval had persistently deeper B-cell depletion, lower annualised attack rates (estimated rate [95% CI]: 0.034 [0.024-0.04] vs 0.086 [0.056-0.12]; p = 0.045), fewer new/enlarging T2 MRI lesions (0.49 [0.43-0.56] vs 1.36 [1.12-1.61]; p < 0.0001), and a trend towards decreased Expanded Disability Status Scale worsening (0.076 [0.06-0.10] vs 0.14 [0.10-0.18]; p = 0.093). Antibodies to inebilizumab, although present in a proportion of treated participants, did not alter outcomes.

Interpretation

This analysis suggests that compared with placebo, inebilizumab can provide specific, rapid, and durable depletion of B cells in participants with NMOSD. Although deep and persistent CD20+ B-cell depletion correlates with long-term clinical stability, early, deep B-cell depletion correlates with improved disease activity metrics in the first 2 years.

Funding

Horizon Therapeutics (formerly from Viela Bio/MedImmune).

Background

The N-MOmentum trial investigated safety and efficacy of inebilizumab in participants with neuromyelitis optica spectrum disorder (NMOSD).

Objective

Evaluate the attack identification process and adjudication committee (AC) performance in N-MOmentum.

Methods

Adults (n = 230) with NMOSD and Expanded Disability Status Scale score ⩽8 were randomized (3:1) to inebilizumab 300 mg or placebo. The randomized controlled period was 28 weeks or until adjudicated attack. Attacks were adjudicated according to 18 predefined criteria. Magnetic resonance imaging (MRI) and biomarker (serum glial fibrillary acidic protein [sGFAP]) analyses were performed.

Results

A total of 64 participant-reported neurological events occurred; 51 (80%) were investigator-determined to be attacks. The AC confirmed 43 of the investigator-determined attacks (84%). There was high inter- and intra-AC-member agreement. In 25/64 events (39%) and 14/43 AC-adjudicated attacks (33%), MRI was reviewed during adjudication. Retrospective analysis revealed new domain-specific T1 and T2 MRI lesions in 90% of adjudicated attacks. Increased mean sGFAP concentrations (>2-fold change) from baseline were observed in 56% of adjudicated attacks versus 14% of investigator-determined attacks rejected by the AC and 31% of participant-reported events determined not to be attacks.

Conclusion

AC adjudication of NMOSD attacks according to predefined criteria appears robust. MRI lesion correlates and sGFAP elevations were found in most adjudicated attacks.

To assess treatment effects on Expanded Disability Status Scale (EDSS) score worsening and modified Rankin Scale (mRS) scores in the N-MOmentum trial of inebilizumab, a humanized anti-CD19 monoclonal antibody, in participants with neuromyelitis optica spectrum disorder (NMOSD). Adults (N = 230) with aquaporin-4 immunoglobulin G-seropositive NMOSD or -seronegative neuromyelitis optica and an EDSS score ≤8 were randomized (3:1) to receive inebilizumab 300 mg or placebo on days 1 and 15. The randomized controlled period (RCP) was 28 weeks or until adjudicated attack, with an option to enter the inebilizumab open-label period. Three-month EDSS-confirmed disability progression (CDP) was assessed using a Cox proportional hazard model. The effect of baseline subgroups on disability was assessed by interaction tests. mRS scores from the RCP were analyzed by the Wilcoxon-Mann-Whitney odds approach. Compared with placebo, inebilizumab reduced the risk of 3-month CDP (hazard ratio [HR]: 0.375; 95% CI: 0.148-0.952; p = 0.0390). Baseline disability, prestudy attack frequency, and disease duration did not affect the treatment effect observed with inebilizumab (HRs: 0.213-0.503; interaction tests: all p > 0.05, indicating no effect of baseline covariates on outcome). Mean EDSS scores improved with longer-term treatment. Inebilizumab-treated participants were more likely to have a favorable mRS outcome at the end of the RCP (OR: 1.663; 95% CI: 1.195-2.385; p = 0.0023). Disability outcomes were more favorable with inebilizumab vs placebo in participants with NMOSD. This study provides Class II evidence that for patients with NMOSD, inebilizumab reduces the risk of worsening disability. N-MOmentum is registered at ClinicalTrials.gov: NCT02200770.