Vistagen's randomized Phase 3 trial of fasedienol failed its primary endpoint in June. Three months later, data from patients who kept taking the drug without a control arm to compare against shows their anxiety scores steadily improving.
The extension enrolled 322 patients who chose to continue using the nasal spray after the controlled trial ended, taking it as needed in everyday situations. Over four months, their mean score on a standard social anxiety scale — where the group started at 99.3, in the most severe category on a 0-to-144 range — fell by about 31 points. By month four, 65% of participants had improved by at least 20 points.
The limitation is plain. A controlled trial includes a placebo arm precisely because patients in open-label studies — where everyone knows they are taking the drug — tend to improve for reasons unrelated to the drug itself. The Phase 3 that failed was designed to account for that; the extension was not. Vistagen says the data adds to the case for fasedienol, and the company says it is preparing to meet with the FDA this quarter to propose a new registrational trial.
Safety data from the extension showed a 1.6% rate of discontinuation due to adverse events — five patients among the 322 — with none attributed to fasedienol. More than 95% of side effects were mild or moderate. Headache was the most common complaint.
Shares closed 46.54% higher at $0.3684 after the company released the open-label data, on dollar volume of about $241 million.
Vistagen has no approved products. The FDA meeting has not been scheduled, and the company has not said what design or endpoints it would propose for a new trial.