Vistagen hits pause on social anxiety nasal spray trial

Feb. 8, 2023

Vistagen has hit the pause button on its plans to resume its phase 3 trial of its potential first-in-class nasal spray for the treatment of social anxiety disorder (SAD).

Back in Sept., the California-based biotech said it was going to move forward with its PALISADE-2 trial, based on the outcome of an interim analysis and the recommendation of outside scientists. Following disappointing results from a previous trial, PALISADE-1, the company had recruited independent biostatisticians to conduct an interim analysis and map out the best course of action for PALISADE-2 — leading the Vistagen to decide to continue the trial as planned to the full enrollment of 208 subjects, without any adjustment to the size of the study. 

Vistagen was expecting topline results from PALISADE-2 — which was assessing drug candidate PH94B as an acute treatment of anxiety in adults with SAD — in the first half of 2023.

Now it seems that isn't happening. In a corporate update and financial results report, Vistagen revealed that "it is not yet advisable to make a decision about resuming PALISADE-2 before discussing its broader phase 3 development plan for PH94B with the FDA."

PH94B is a  synthetic investigational neurosteroid developed from proprietary compounds called pherines. With its novel mechanism of action, PH94B is a nasal spray administered at microgram-level doses and designed to achieve rapid-onset anti-anxiety, or anxiolytic, effects.

Vistagen said it also wants to further assessing the potential impact of the proposed adjustments to its trial protocol in light of its peers' recent study failures in SAD.

Back in Dec., Australia-based Bionomics revealed that its selective negative allosteric modulator of the α7 nicotinic acetylcholine receptor failed to meet primary endpoint in a phase 2 trial in SAD.

Vistagen said it is currently preparing to meet with the FDA to discuss its broader phase 3 development plan for PH94B.