Vemircopan for generalized myasthenia gravis misses mark in phase 2 study

The oral, selective factor D inhibitor vemircopan has shown no evidence of benefit in the treatment of adult patients with acetylcholine receptor antibody-positive (AChR-Ab+) generalized myasthenia gravis in a phase 2 trial.

The trial consisted of a screening period; an 8-week, double-blind, primary evaluation period; a 26-week blinded extended treatment period; and an open-label extension (OLE) period of up to approximately 1.5 years.

A total of 70 patients (mean age at diagnosis 45.4 years, 54 percent female) with Myasthenia Gravis–Activities of Daily Living (MG-ADL) score of ≥5 and Myasthenia Gravis Foundation of America classes II through IV participated in the trial. They were randomly assigned to receive treatment with vemircopan at 180 mg (n=28) or 120 mg (n=14) or placebo (n=28). Treatment was administered orally twice daily.

The primary endpoint was the proportion of patients achieving a ≥2-point reduction in MG-ADL total score from baseline for 4 consecutive weeks, without rescue therapy, during the 8-week, double-blind primary evaluation period. Secondary endpoints included MG-ADL total score, Quantitative Myasthenia Gravis total score, and Neurological Disorders Fatigue questionnaire score.

The trial was terminated due to futility. The proportion of participants achieving the primary endpoint did not differ significantly between the vemircopan 180- and 120-mg groups and the placebo group (57 percent and 57 percent vs 64 percent, respectively).

Results for the secondary endpoints were also similar across the treatment groups.

None of the patients contracted meningococcal infection during the trial. One patient died due to hepatic failure, and another discontinued study treatment due to herpes simplex meningitis.