Zai Lab and argenx announced positive results from a Phase 3 clinical trial evaluating efgartigimod in adult patients with generalized myositis.
The trial met its primary endpoint, demonstrating a statistically significant improvement in disease control compared to placebo, the companies said in a joint statement. Key secondary endpoints were also achieved, including reductions in muscle weakness and improvements in patient-reported outcomes.
Efgartigimod, an FcRn inhibitor, targets the neonatal Fc receptor to reduce pathogenic immunoglobulin G antibodies, a mechanism previously validated in other autoimmune conditions. The drug is being developed as a potential treatment for generalized myositis, a rare and debilitating autoimmune disease characterized by muscle inflammation and weakness.
Zai Lab holds exclusive rights to develop and commercialize efgartigimod in Greater China, while argenx retains global rights outside the region. The companies did not disclose further details on regulatory timelines or commercialization plans in the announcement.
Myositis affects an estimated 10 to 15 per 100,000 people worldwide, with limited treatment options currently available. Positive Phase 3 data could support regulatory submissions for efgartigimod in generalized myositis, pending further review by health authorities.
