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Argenx says efgartigimod met main goal in myositis trial

By Thomson Reuters Aug 17, 2026 | 12:27 AM

Aug 17 (Reuters) – Belgian-Dutch immunology company argenxARGX.BR said its drug efgartigimod met the primary endpoint in ​a late-stage study treating adults ‌with autoimmune myositis, showing significant improvement in disease activity.

The Phase 3 trial demonstrated rapid and sustained benefits over a placebo ‌for ​two subtypes of the ⁠muscle-weakening disease, including ⁠one that currently has no approved therapies.

TRIAL RESULTS

• Patients treated with the drug had a 15.4-point greater ​improvement in mean total improvement score at 52 weeks compared to ⁠a placebo.

• The study ⁠is the first Phase ​3 trial to show significant improvements in ​immune-mediated necrotizing myopathy, a disease subtype ‌lacking approved options.

• While patients with the dermatomyositis subtype saw similar clinical improvements, the smaller cohort did ⁠not reach statistical significance, the company said.

• The drug was well-tolerated by patients, showing ⁠a ‌safety profile consistent with prior ⁠trials, argenx said.

• “These are ​the ‌first Phase 3 results to ​show that ⁠precision targeting of FcRn with efgartigimod can deliver meaningful benefit in this disease,” Chief Medical Officer Luc Truyen said.

(Reporting by Lucie Barbier; Editing by ​Matt Scuffham)