VistaGen Therapeutics (NASDAQ:VTGN) provided an update on its lead drug candidate fasedienol and its ongoing Phase III PALISADE program, highlighting efforts to address variability seen in a recent study and reiterating expected timing for a key upcoming readout. President and CEO Shawn Singh discussed the company’s analysis of prior PALISADE trials, operational changes being implemented in the current study, and how advanced analytics could influence the statistical approach before the database is locked.
Fasedienol and the PALISADE Phase III program
Singh described fasedienol as a “rapid onset, non-systemic, intranasal” product candidate being developed under Fast Track designation for the acute treatment of social anxiety disorder. He said the condition can begin in adolescence and is characterized by fear of embarrassment, humiliation, or judgment in everyday social and performance situations. Fasedienol is intended to reduce the “wave of anxiety” people feel right before or during an anxiety-provoking social or performance event.
What the company says it learned from PALISADE-3
Singh said PALISADE-3 provided an opportunity to step back and review the broader dataset across PALISADE-1, PALISADE-2, and PALISADE-3. According to Singh, when VistaGen analyzed those trials together, the fasedienol treatment effect appeared “pretty constant,” while the placebo effect was the primary source of variability.
He said that insight has informed the company’s approach to PALISADE-4, including a focus on operational execution and placebo mitigation strategies. Singh pointed to measures such as:
- Additional site training
- Refinement of recruitment channels
- Optimization of certain sites
- Careful monitoring of how sites execute the Public Speaking Challenge to improve consistency
Singh also noted that site experience can matter, including experience with the protocol and the number of subjects randomized at a given site.
AI, machine learning, and vocal biomarkers
Singh emphasized that the PALISADE program now has a “richness of the dataset,” given the amount of data generated by the Public Speaking Challenge. He said VistaGen is leveraging AI and machine learning across historical PALISADE data to look for patterns that may explain variability, including using collaborator tools and “proprietary AI advanced neural network approaches” to evaluate vocal biomarkers.
As an example, Singh said PALISADE-3 speeches were recorded and are being evaluated for behavioral indicators of anxiety and other potential covariates that could help explain or influence SUDS (Subjective Units of Distress Scale) responses. The stated goal is to better understand drivers of both treatment and placebo responses and assess whether any variables could inform the PALISADE-4 statistical analysis plan (SAP) before database lock. Singh said any changes to the SAP would need to occur before the database lock and would relate to whether a covariate could have a fixed effect in the analysis.
Mechanism and evidence of activity discussed
Singh described fasedienol as part of a class the company calls “pherines,” which are delivered in microgram doses to chemosensory neurons in the nasal cavity rather than circulating systemically. He said these neurons project to brain regions involved in emotional regulation, including the amygdala, and that measurable blood levels are typically not detected, requiring different approaches than traditional PK/PD studies.
He said the company has conducted 15 Phase I studies over time to understand dosing and biological activity, along with in vitro work including calcium imaging and studies on nasal mucosal cells. Singh also described studies using “electrogram of nasal receptors” (EGNR) to measure local receptor depolarization, which he said helped inform dose selection. He added that at higher doses, the company saw minimal impact on receptor response. Singh also referenced studies involving electrograms of the olfactory bulbs, describing a signaling cascade in which receptor activation is observed “in milliseconds” after administration, with signals relayed to the olfactory bulbs and then to the amygdala.
Regulatory path, broader pipeline, and cash runway
On the regulatory pathway, Singh said the company is pursuing the conventional expectation of two adequate and well-controlled Phase III studies, supplemented by additional materials to support clinical meaningfulness and duration of effect, along with other standard components such as a human factors study and a rounded safety database. He said the safety database is “approaching near the full 1,500 exposures,” aided by open-label studies.
Singh also said VistaGen believes PALISADE-2 is “registration worthy” and could anchor an NDA together with a successful PALISADE-4, while noting that FDA review ultimately determines acceptability. He discussed the importance of concordance across endpoints, noting that CGI and PGIC are secondary endpoints and that the company values concordance such as what it reported in PALISADE-2.
Separately, Singh said the company hopes to have additional data related to an open-label component by the end of the first half of the year, describing it as helpful for understanding real-world utilization and impacts over time (including under the Liebowitz scale) compared with the minute-by-minute SUDS measures used in the Public Speaking Challenge.
On the rest of the pipeline, Singh said VistaGen has five assets and that all have achieved clinical success in at least a Phase IIa study. He highlighted a hot flashes program that he described as non-hormonal, non-systemic, and rapid onset, and said the company hopes to have its IND cleared by the end of the first half of the year. Singh added that, by the end of the fourth quarter, the company hopes both its depression program and hot flashes program are “staged for further clinical development,” either internally or with collaborators.
Finally, Singh stated that VistaGen’s cash runway extends into 2027.
About VistaGen Therapeutics (NASDAQ:VTGN)
VistaGen Therapeutics, Inc (NASDAQ:VTGN) is a clinical-stage biopharmaceutical company dedicated to the discovery and development of next-generation medicines for central nervous system disorders. Incorporated in Delaware in 1998 and headquartered in South San Francisco, California, VistaGen applies advanced human pluripotent stem cell technologies to accelerate drug candidate validation and optimization. The company’s core focus is on addressing unmet medical needs in major depressive disorder, neuropathic pain and dermatological conditions.
The company’s lead candidate, AV-101, is an oral prodrug designed to modulate glutamatergic neurotransmission via the N-methyl-D-aspartate (NMDA) receptor pathway, with clinical programs targeting major depressive disorder and neuropathic pain.
