Vemircopan holds little benefit in generalized myasthenia gravis

The oral, selective factor D inhibitor vemircopan falls short of meeting the prespecified threshold for efficacy in the treatment of generalized myasthenia gravis, as shown in a phase 2 trial.

The trial consisted of a ≤4-week 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 adult patients (mean age at diagnosis 45.4 years, 54 percent female) with acetylcholine receptor antibody-positive (AChR-Ab+) generalized myasthenia gravis, Myasthenia Gravis–Activities of Daily Living (MG-ADL) score of ≥5, and Myasthenia Gravis Foundation of America classes II–IV participated in the trial. These patients were randomly assigned to receive vemircopan at 180 mg (n=28) or 120 mg (n=14) or placebo (n=28). Treatment was administered orally, twice daily.

The trial was terminated early. The primary endpoint of the proportion of patients achieving a ≥2-point reduction in MG-ADL total score for 4 consecutive weeks, without rescue therapy, during the 8-week primary evaluation period did not significantly differ between vemircopan and placebo: 57 percent with 180 mg, 57 percent with 120 mg, and 64 percent with placebo.

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

One patient died due to hepatic failure, and another patient discontinued treatment due to herpes simplex meningitis. There were no cases of meningococcal infection documented.