Firdapse amifampridine: Phase III data
Top-line data from a double-blind, international Phase III trial in 38 patients with LEMS showed that Firdapse met the co-primary endpoints of improving QMG and SGI scores from baseline to day 14 vs. placebo. Patients received Firdapse given 3-4 times daily at a total daily dose of 30-80 mg, except in patients with moderate renal impairment, who received a starting dose of 10 mg. The trial was designed as a withdrawal trial in which all patients received open-label Firdapse during a run-in period of >=91 days. Patients were then randomized to continue on Firdapse or be discontinued to placebo over 2 weeks. Following the double-blind portion of the trial, patients were eligible to receive Firdapse in a 2-year, open-label extension. Clinically significant findings were defined as worsening of symptoms in the placebo arm.
On the co-primary endpoints, QMG score worsened by 2.2 points in the placebo arm (p=0.0452) and SGI score worsened by 2.6 points in the placebo arm (p=0.0028) compared to Firdapse. Firdapse also met the secondary endpoint of improving CGI-I vs. placebo (p=0.0267), but missed the secondary endpoint of improving the timed 25-foot walk test at day 14 (worsening of 9.67 feet/min in the placebo arm compared to Firdapse). Firdapse was generally well tolerated. Data will be presented at the American Neurological Association meeting in Baltimore this month. ...