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An Extra Spray Still Fails to Widen the Gap: Phase 2 Fasedienol Social Anxiety Trial Misses Statistical Significance
In an exploratory trial of 61 adults, both single and repeated nasal dosing improved anxiety scores, but neither outperformed placebo in the primary analyses; the signal in the severe subgroup awaits confirmation in a larger study.
Acute anxiety triggered by social situations often comes on quickly, making it difficult for patients to respond in the moment. Vistagen hopes to address this treatment gap with the as-needed nasal spray fasedienol, but the latest exploratory Phase 2 trial showed that adding a second dose did not produce a clear, statistically supported advantage.
This U.S. multicenter study, registered as NCT06809179 and designated by the company as trial PH94B-CL036, enrolled 61 adults with social anxiety disorder. In a stressful simulated public-speaking setting, participants were randomly assigned to receive two doses of fasedienol, fasedienol followed by placebo, or two doses of placebo. The doses were administered 10 minutes apart, with each fasedienol dose containing 3.2 micrograms.
Topline results released by Vistagen showed that both single and repeated dosing produced numerical improvements in anxiety scores compared with placebo, but neither primary analysis reached statistical significance. In other words, the available data are not sufficient to rule out the possibility that these differences were due to random variation, nor do they demonstrate that a second nasal spray can reliably strengthen or prolong the effect.
The company also said the efficacy signal was stronger in a prespecified subgroup of participants whose symptoms were classified as “very severe,” with some comparisons reaching nominal significance without adjustment for multiple testing. However, the subgroup necessarily included fewer than the overall 61 participants. Given that the primary endpoint in the overall population was not met, these results are more appropriately used to generate hypotheses for subsequent trials and cannot be regarded as independent proof of efficacy.
The study was small and was primarily intended to explore dose response, repeat-dosing intervals, and duration of action. The company has released only topline data, without complete scores for each group, effect sizes, confidence intervals, or detailed safety results. It is therefore not yet possible to determine whether the numerical differences are clinically meaningful or which patients might truly benefit.
The trial registration also includes an optional open-label extension allowing participants to use 3.2 micrograms of fasedienol as needed, up to six times daily for as long as 12 months, to supplement longer-term safety and tolerability data. However, open-label observation lacks a placebo comparison and cannot make up for the randomized trial’s failure to provide statistically significant efficacy evidence. For Vistagen, these results offer direction for further research, but they also underscore once again that advancing a registration application will require a credible effect to be reproduced in a larger controlled trial using a prespecified population and endpoints.