Vistagen (NASDAQ: VTGN) announced that its clinical program for fasedienol nasal spray has achieved minimum patient exposure recommendations under ICH E1 international regulatory standards for drugs intended for long-term treatment of non-life-threatening conditions.

As of May 31, 2026, the company reports over 1,500 subjects received at least one exposure to fasedienol, with over 300 subjects having at least six months of exposure and over 100 subjects with at least 12 months of exposure. These figures represent estimates of subjects who completed visits in fasedienol open-label safety studies.

The exposure numbers include participants from ongoing open-label extensions of Vistagen's PALISADE-3 and PALISADE-4 Phase 3 studies, as well as a Phase 2 repeat dose study. The company has not yet aligned with the FDA on specific patient exposure requirements for a potential new drug application submission.

"Achieving ICH E1 minimum safety exposure recommendations for fasedienol marks another important milestone in our social anxiety disorder program," said Shawn Singh, President and Chief Executive Officer. "We are encouraged to reach this level of exposure, with fasedienol having been well-tolerated across our completed clinical trials to date."

Topline results from the randomized, double-blind, placebo-controlled portion of PALISADE-4 are expected in the second quarter of 2026. Results from the Phase 2 repeat dose study are expected in the third quarter of 2026.

Fasedienol is an investigational nasal spray for acute treatment of social anxiety disorder. The FDA has granted Fast Track designation for the drug's development. Vistagen is developing the treatment as part of its pherine product candidate class, which targets nose-to-brain neurocircuitry.