Vistagen’s Phase 3 PALISADE-4 trial of intranasal fasedienol in social anxiety disorder did not meet primary endpoints, though safety remained favorable. The company plans a revised FDA strategy focused on long-term treatment using LSAS as the primary endpoint.
Written By: Farha Farheen, PharmD
Reviewed By: Pharmacally Editorial Team
Vistagen has reported topline results from the Phase 3 PALISADE-4 trial (NCT06615557) evaluating intranasal fasedienol for the acute treatment of social anxiety disorder (SAD). The study did not meet its primary or secondary efficacy endpoints in the overall study population, although the investigational therapy maintained a favorable safety and tolerability profile consistent with previous clinical studies.
The company now plans to meet with the U.S. Food and Drug Administration (FDA) to discuss a revised registration strategy focused on long-term treatment of social anxiety disorder using the Liebowitz Social Anxiety Scale (LSAS) as the primary efficacy endpoint in a future Phase 3 study.
Novel intranasal therapy targets anxiety through nose-to-brain neurocircuitry
Fasedienol is Vistagen’s lead investigational intranasal pherine product candidate. Unlike conventional anti-anxiety medications, it is intended to modulate nasal-limbic amygdala neurocircuits involved in fear and anxiety without requiring systemic absorption or direct brain penetration.
The therapy also differs pharmacologically from benzodiazepines, with no observed interaction with GABA-A receptors or brain receptors commonly associated with abuse liability. This approach aims to provide rapid anxiolytic effects while potentially reducing risks such as sedation, dependence, misuse, and drug-drug interactions.
Social anxiety disorder affects more than 30 million adults in the United States and can substantially impair social functioning, employment, and quality of life while increasing the risk of depression, substance use disorders, and suicidal ideation.
PALISADE-4 failed to demonstrate efficacy in the overall study population
PALISADE-4 was a multicenter, randomized, double-blind, placebo-controlled Phase 3 trial that enrolled 238 adults with social anxiety disorder. Participants received a single dose of fasedienol or placebo before a simulated public speaking challenge.
The primary endpoint measured changes in anxiety using the Subjective Units of Distress Scale (SUDS). Fasedienol did not significantly improve SUDS scores compared with placebo (least squares mean difference 1.9; p=0.427). The study also failed to show treatment benefits across secondary efficacy endpoints.
Safety findings remained favorable. Investigators reported good tolerability, and the overall safety profile was consistent with previous placebo-controlled clinical trials.
Post-hoc analysis identified benefit in patients with very severe disease
A post-hoc analysis evaluated 123 participants with very severe social anxiety, defined by a baseline LSAS score of 95 or higher.
Within this subgroup, fasedienol produced a nominally significant reduction in anxiety symptoms compared with placebo. The least squares mean difference on the SUDS endpoint reached -9.1 (p=0.036), suggesting the therapy may provide greater benefit in patients with more severe disease.
Vistagen’s Chief Medical Officer, Dr. Angel Angelov, said that although the primary trial outcome was disappointing, the company was encouraged by the consistent safety profile and the positive efficacy signal observed in patients with very severe social anxiety disorder.
Company shifts development strategy toward long-term treatment
Based on findings across the broader fasedienol development program, Vistagen intends to shift from evaluating acute symptom relief to pursuing long-term treatment of social anxiety disorder.
The company plans to discuss with the FDA a potential registrational pathway involving a single future multi-dose Phase 3 trial using the LSAS as the primary endpoint, supported by positive findings from the earlier PALISADE-2 Phase 3 study and other placebo-controlled clinical data.
Chief Executive Officer Shawn Singh said the company remains focused on disciplined capital management while advancing the most promising opportunities across its neuroscience pipeline. Vistagen expects its current cash resources to fund operations into 2027.
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About the Writer
Farha Farheen, PharmD (LinkedIn) is a pharmacy professional with a strong interest in pharmacovigilance and clinical research. She has completed her Doctor of Pharmacy (Pharm.D) along with her internship as a Clinical Pharmacist. She has hands-on experience in adverse drug reaction (ADR) reporting, safety data documentation, and pharmacovigilance workflows, and is proficient in using VigiFlow. She is also a patent holder for an antibacterial formulation enriched with bioactive substances, granted by the German Patent and Trademark Office.