To illustrate the clinical meaningfulness of change in score in Myasthenia Gravis (MG) Symptoms Patient-Reported Outcome (PRO) scales in patients receiving one cycle of rozanolixizumab in the MycarinG study.

In the Phase 3 MycarinG study (NCT03971422), one 6-week cycle of rozanolixizumab significantly improved Myasthenia Gravis Activities of Daily Living (MG-ADL) scores, with 70.6% of patients receiving rozanolixizumab and 31.3% of patients receiving placebo achieving MG-ADL response at Day 43. In the novel MG Symptoms PRO scales, rozanolixizumab treatment significantly improved muscle weakness fatigability, physical fatigue and bulbar muscle weakness scores at Day 43, based on responder thresholds determined using anchor- and distribution-based methods as defined in a post-hoc analysis of Day 29 data.

Patients received rozanolixizumab 7 mg/kg or 10 mg/kg, or placebo. Change from baseline to Day 43 in the MG Symptoms PRO scales was assessed and thresholds for clinically meaningful response applied: a decrease of ≥16.67 points for muscle weakness fatigability and a decrease of ≥20.00 points for physical fatigue and bulbar muscle weakness.

Muscle weakness fatigability: meaningful improvement at Day 43 was achieved by 46.9% (30/64), 56.5% (35/62) and 28.1% (18/64) of patients receiving rozanolixizumab 7 mg/kg, 10 mg/kg, and placebo, respectively, using the –16.67 threshold. Physical fatigue: meaningful improvement was achieved by 31.3% (20/64), 48.4% (30/62) and 26.6% (17/64) of patients receiving rozanolixizumab 7 mg/kg, 10 mg/kg, and placebo, respectively, using the ?20.00 threshold. Bulbar muscle weakness: meaningful improvement was achieved by 26.6% (17/64), 32.3% (20/62) and 10.9% (7/64) of patients receiving rozanolixizumab 7 mg/kg, 10 mg/kg, and placebo, respectively, using the ?20.00 threshold.

This post-hoc analysis found that a higher percentage of patients treated with rozanolixizumab than placebo had meaningful improvements in physical fatigue and muscle weakness fatigability symptoms, which are identified by patients as significant but not captured by the commonly used MG-ADL assessment.