Remission is a key goal in gMG and achieving minimal symptom expression (MSE) with claseprubart is a key treatment objective.

The classical complement pathway plays a significant role in generalized myasthenia gravis (gMG) pathology. Claseprubart is a potent monoclonal antibody that selectively targets the classical pathway by inhibiting active C1s (aC1s).

MaGic (NCT06282159), is a global Phase 2, randomized, double-blind, placebo-controlled trial. Patients treated with claseprubart (300mg, Q2W) were evaluated for MSE (MG-ADL ≤1 or QMG ≤3) compared with placebo. p-values were one-sided and nominal significance was assessed at an alpha= 0.1. Outcomes include proportion of patients achieving MSE at Week 13 and anytime during the study, earliest timepoint of MSE achievement, and durability defined as sustained MSE for at least 6 weeks.

At Week 13, 37% of claseprubart treated patients achieved MG-ADL-MSE versus 14% with placebo (OR 3.81; p=0.0550). 43% achieved MG-ADL-MSE at least once during the study versus 14% of placebo (OR: 4.72; p=0.0231). This effect was observed as early as Week 1 (median time to response was Week 3). Sustained remission-like states (for at least 6 weeks) were seen in all patients who achieved MSE. Similar results were observed using QMG minimum symptom expression threshold.

Claseprubart patients were more than four times more likely to achieve MSE than placebo patients and MSE was observed as early as week 1. Patients who achieved MSE maintained responses for at least 6 weeks. These results highlight the therapeutic potential of aC1s inhibition in AChR+ gMG.