What were the key findings of the MycarinG trial?

Q: What were the key findings of the MycarinG trial?

MycarinG is a Phase 2 randomized trial of efgartigimod (FcRn antagonist) in anti-MuSK myasthenia gravis. Efgartigimod significantly reduced MuSK antibody levels and improved MG symptoms. Small sample — proof-of-concept for FcRn-targeting therapy in MuSK-MG.

MycarinG

(2023)

Objective

To assess the safety and efficacy of rozanolixizumab, a neonatal Fc receptor (FcRn) blocker, in patients with acetylcholine receptor (AChR) or muscle-specific kinase (MuSK) autoantibody-positive generalized myasthenia gravis

Study Summary

• Rozanolixizumab 7 mg/kg and 10 mg/kg both significantly improved MG-ADL scores vs placebo at day 43 (LSM difference −2.59 and −2.62; p<0.0001)
• Response rates (≥2-point MG-ADL improvement) were 72% and 69% for 7 mg/kg and 10 mg/kg vs 31% for placebo
• Both doses were generally well tolerated with headache as the most common adverse event (45% and 38% vs 19%)

Intervention

Subcutaneous rozanolixizumab 7 mg/kg or 10 mg/kg once weekly for 6 weeks vs placebo

Inclusion Criteria

Adults ≥18 years with AChR or MuSK autoantibody-positive generalized myasthenia gravis (MGFA class II–IVa), MG-ADL score ≥3 (non-ocular), QMG score ≥11, bodyweight ≥35 kg

Study Design

Arms: Rozanolixizumab 7 mg/kg, Rozanolixizumab 10 mg/kg, Placebo

Patients per Arm: 66 (7 mg/kg), 67 (10 mg/kg), 67 (placebo)

Outcome

• Primary: MG-ADL change from baseline to day 43: −3.37 (7 mg/kg), −3.40 (10 mg/kg) vs −0.78 (placebo); p<0.0001 for both
• Secondary: QMG improvement −5.40 and −6.67 vs −1.92; MGC improvement −5.93 and −7.55 vs −2.03
• 100% of MuSK-positive patients on rozanolixizumab achieved MG-ADL response vs 14% placebo

Bottom Line

MycarinG is a Phase 2 randomized trial of efgartigimod (FcRn antagonist) in anti-MuSK myasthenia gravis. Efgartigimod significantly reduced MuSK antibody levels and improved MG symptoms. Small sample — proof-of-concept for FcRn-targeting therapy in MuSK-MG.

Major Points

Phase 2 proof-of-concept for efgartigimod (FcRn antagonist) in anti-MuSK MG.
Efgartigimod reduces IgG4 (the pathogenic antibody class in MuSK-MG) by blocking FcRn recycling.
MuSK antibody levels significantly reduced with efgartigimod treatment.
Clinical improvement measured by MG-ADL and QMG scores.
Small sample — not powered for definitive efficacy. Open-label.
FcRn inhibition is particularly relevant for MuSK-MG (IgG4-mediated, unlike AChR-MG which is IgG1/3).
Supports efgartigimod (Vyvgart) expansion from AChR-MG to MuSK-MG population.
Argenx sponsored.

Study Design

Primary Outcome

Control	Intervention	HR/OR	P-value
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MycarinG

Bottom Line

Major Points

Design

Inclusion Criteria

Outcomes

Ask about MycarinG

MycarinG

Objective

Study Summary

Intervention

Inclusion Criteria

Study Design

Outcome

Bottom Line

Major Points

Study Design

Primary Outcome