PALISADE-4 was a U.S. multi-center, randomized, double-blind, placebo-controlled Phase 3 clinical trial designed to evaluate the efficacy, safety, and tolerability of a single dose of fasedienol in reducing anxiety symptoms in adults with social anxiety disorder during a simulated anxiety-provoking public speaking challenge with the Subjective Units of Distress Scale (SUDS) as the primary endpoint.

In the overall trial population (n=238), fasedienol did not achieve its primary endpoint, as measured by the least squares (LS) mean change from baseline on the SUDS score for fasedienol (-9.5+/-1.7 standard error (SE)) compared with placebo (-11.4+/-1.7 SE), with a difference in the LS means of 1.9 (p=0.427). There was no treatment difference between fasedienol and placebo for the secondary endpoints. Favorable safety and tolerability data of fasedienol were consistent with previous placebo-controlled clinical trials.

In a post-hoc analysis of a subpopulation of patients with very severe social anxiety defined by a baseline score at screening of 95 or greater on the Liebowitz Social Anxiety Scale (LSAS) (n=123)1, fasedienol was nominally statistically significant as measured by the LS mean change from baseline on the SUDS score for fasedienol (-12.8+/-3.4 SE) compared with placebo (-3.7 +/-3.4 SE), with a difference in the LS means of -9.1 (p=0.036).

Based on the totality of data to date from the fasedienol development program in social anxiety disorder, Vistagen plans to transition from the acute treatment of social anxiety disorder symptoms to a potential registrational pathway focused on the overall treatment of social anxiety disorder over time. Informed by U.S. Food and Drug Administration (FDA) Draft Guidance to Industry published in June 2026 (Demonstrating Substantial Evidence of Effectiveness for Human Drug and Biological Products)2, Vistagen plans to meet with the FDA to discuss a registrational pathway for fasedienol potentially supported by a single, future multi-dose Phase 3 trial with the LSAS as the primary endpoint, consistent with regulatory precedent supporting previously-approved drugs based on the LSAS for the treatment of social anxiety disorder, and confirmatory evidence from its positive PALISADE-2 Phase 3 trial and other placebo-control clinical trials in the fasedienol development program, as well as what the Company believes to be sufficient aggregate safety data. The LSAS is a 24-item instrument used by clinical researchers to measure fear, anxiety, and avoidance of social and performance situations to assess the severity of social anxiety disorder.