Symptom severity assessment using MG-ADL items and domains in a 24-week, phase 3 study (Vivacity) of nipocalimab in generalized Myasthenia Gravis

Topic:

Clinical Trials

Poster Number: P354

Author(s):

Constantine Farmakidis, MD, University of Kansas Medical Center, Kansas City, KS, USA, Kavita Gandhi, Johnson & Johnson, Raritan, NJ, USA, Maria Ait-Tihyaty, PhD, Johnson & Johnson, Titusville, NJ, USA, Ibrahim Turkoz, Johnson & Johnson, Titusville, NJ, USA, Sheryl Pease, Johnson & Johnson, Raritan, NJ, USA, Zia Choudhry, MD, PhD, Johnson & Johnson, Titusville, NJ, USA, Charlotte Gary, Johnson & Johnson, Issy-les-Moulineaux, France, Antoine C El Khoury, Johnson & Johnson, Raritan, NJ, USA, Sindhu Ramchandren, MD, MS, Johnson & Johnson, Titusville, NJ, USA

BACKGROUND: Nipocalimab, a neonatal fragment crystallizable receptor blocker, as an add-on to standard-of-care (SOC) demonstrated statistically significant improvement in Myasthenia Gravis-Activities of Daily Living (MG-ADL) compared with placebo+SOC in a 24-week double-blind phase 3 study in patients with generalized myasthenia gravis.
OBJECTIVE: Post-hoc analyses were conducted to evaluate improvements in distinct muscle function groups using MG-ADL items and domains for nipocalimab+SOC versus placebo+SOC.
METHODS: Baseline floor effects (score=0) distribution was evaluated with median/mean item and domain scores. Mean change from baseline for four domains (bulbar, respiratory, limb, and ocular) were evaluated at 24-weeks and analysis of variance tested treatment differences with nipocalimab+SOC versus placebo+SOC. Based on items/domains score distributions, responders were defined using within-person change threshold of 1-point for items and 2-points for domains except for the 1-item respiratory domain with 1-point threshold. Generalized-estimating-equations evaluated improvement likelihood in items/domains over 24-weeks.
RESULTS: In 153 patients, median baseline MG-ADL item scores were 1.0-2.0 (range 0-3). Mean (range) domain scores in nipocalimab+SOC and placebo+SOC were bulbar [2.7 (0-7), both arms], limb [2.4 (0-5); 2.5 (0-5)], ocular [3.5 (0-6); 2.8 (0-6)] and respiratory [1.1 (0-2); 1.0 (0-2), item], respectively. Mean change from baseline for MG-ADL domains except ocular were significantly higher in nipocalimab+SOC versus placebo+SOC (p<0.05). Proportion achieving MG-ADL item response ranged from 42.7% (swallowing) to 97.6% (respiratory) over 24-weeks favoring nipocalimab+SOC. The odds-ratio (95% CI) of MG-ADL domain responder over 24-weeks were, bulbar 1.6 (0.9-2.7), respiratory 2.0 (1.0-3.6), limb 1.8 (1.0-3.1) and ocular 2.9 (1.5-5.4), all favoring nipocalimab+SOC. CONCLUSIONS: MG-ADL total score changes were driven by item and domain-level symptom improvements in all muscle function groups favoring nipocalimab+SOC versus placebo+SOC. © 2024 MGFA Scientific Session at AANEM