Momenta Pharmaceuticals, Inc. announced positive topline data from an interim analysis of its Phase 2 Vivacity-MG study of nipocalimab (M281) in generalized myasthenia gravis (gMG). All four treatment arms showed efficacy in the myasthenia gravis activities of daily living (MG-ADL) score, the primary endpoint. Additionally, all dosing arms showed strong safety and tolerability profiles. The Vivacity-MG study, initiated April 2019, is a Phase 2, multicenter, randomized double-blind, placebo-controlled study evaluating the safety, efficacy, pharmacokinetics and pharmacodynamics of nipocalimab in 68 patients with moderate-to-severe generalized MG (gMG). The 8-week treatment period included four active arms (5 mg/kg every 4 weeks, 30 mg/kg every 4 weeks, 60 mg/kg every two weeks, and a 60 mg/kg single dose) and one placebo arm. The primary endpoint of the study was to reach statistically significant change from the baseline score of the myasthenia gravis Activities of Daily Living (MG-ADL) score. 52% of patients who received nipocalimab had rapid, significant and durable reductions in MG-ADL scores (at least a 2-point reduction from baseline for at least 4 consecutive weeks) across all four dosing arms, versus 15% of placebo treated patients (p=0.017); A statistically significant relationship was observed between IgG reduction and clinical benefit for patients taking nipocalimab (p<0.0001); Patients across all four nipocalimab dosing arms showed rapid reductions in MG-ADL scores, with clinically meaningful changes from baseline within two weeks; Nipocalimab (M281) was well tolerated, safe and efficacious in gMG patients. There were no severe or serious nipocalimab-related adverse events and most adverse events were characterized as mild; and the study findings support continued clinical development in gMG and subcutaneous formulation dose selection.