VistaGen Therapeutics, Inc. (NASDAQ: VTGN) is a biopharmaceutical company committed to developing and commercializing a new generation of medicines with the potential to go beyond the current standard of care for anxiety, depression and other central nervous system (CNS) disorders. Our CNS pipeline includes three product candidates, PH94B, PH10 and AV-101, each with a differentiated profile, favorable safety results observed in all clinical studies to date, and therapeutic potential in multiple CNS indications.
PH94B Nasal Spray
PH94B is a synthetic investigational neurosteroid developed from proprietary compounds called pherines. With its novel mechanism of action, PH94B is an odorless nasal spray administered at microgram-level doses to achieve rapid-onset anti-anxiety, or anxiolytic, effects. The pharmacological activity of PH94B is fundamentally differentiated from that of all FDA-approved anti-anxiety drugs, including all antidepressants approved by the U.S. Food and Drug Administration (FDA) for treatment of social anxiety disorder (SAD), as well as all benzodiazepines and beta blockers prescribed on an off-label basis. PH94B engages peripheral chemosensory receptors in nasal passages that trigger a subset of neurons in the main olfactory bulbs (OB) at the base of the brain. The OB neurons then stimulate inhibitory GABAergic neurons in the limbic amygdala, decreasing the activity of the sympathetic nervous system, and facilitating fear extinction activity of the limbic-hypothalamic system, the main fear and anxiety center in the brain, as well as in other parts of the brain. Importantly, PH94B does not require systemic uptake and distribution to produce its rapid-onset anti-anxiety effects. Our ongoing PALISADE Phase 3 program for PH94B is designed to further demonstrate its potential as a fast-acting, non-sedating, non-addictive acute treatment of anxiety in adults with SAD. We believe PH94B also has potential to be developed as a novel treatment for adjustment disorder with anxiety, postpartum anxiety, post-traumatic stress disorder, procedural anxiety, panic and other anxiety disorders. PH94B has been granted Fast Track designation status by the FDA for development for the acute treatment of SAD.
PH10 Nasal Spray
PH10 is a synthetic investigational neurosteroid, which also was developed from proprietary compounds called pherines. Its novel, rapid-onset mechanism of action (MOA) is fundamentally differentiated from the MOA of all current treatments for MDD and other depression disorders. PH10 is self-administered at microgram-level doses as an odorless nasal spray. PH10 activates nasal chemosensory cells in the nasal passages, connected to neural circuits in the brain that produce antidepressant effects. Specifically, PH10 engages peripheral chemosensory receptors in the nasal passages that trigger a subset of neurons in the main OB that stimulate neurons in the limbic amygdala. This is turn increases activity of the limbic-hypothalamic sympathetic nervous system and increases the release of catecholamines. Importantly, unlike all currently approved oral antidepressants, PH10 does not require systemic uptake and distribution to produce rapid-onset of antidepressant effects. In all clinical studies to date, PH10 has not caused psychological side effects (such as dissociation and hallucinations) or safety concerns that may be associated with rapid-onset ketamine-based therapy, including intravenous ketamine or intranasal ketamine (esketamine). We believe PH10 has potential to be a new stand-alone treatment for MDD and several other depression disorders.
AV-101, an Oral NMDAR Glycine Site Antagonist
AV-101 (4-Cl-KYN) is an investigational prodrug designed to be orally administered and to target the NMDAR (N-methyl-D-aspartate receptor), an ionotropic glutamate receptor in the brain. Abnormal NMDAR function is associated with numerous CNS diseases and disorders. AV-101 is an oral prodrug of, 7-chloro-kynurenic acid (7-Cl-KYNA), which is a potent and selective full antagonist of the glycine co-agonist site of the NMDAR that inhibits the function of the NMDAR. However, unlike ketamine and many other NMDAR antagonists, 7-Cl-KYNA is not an ion channel blocker. At doses administered in all studies to date, AV-101 has been observed to be orally bioavailable, well-tolerated and has not exhibited dissociative or hallucinogenic psychological side effects or safety concerns. We are currently preparing to evaluate AV-101’s therapeutic potential in combination with probenecid in a Phase 1B clinical study. The FDA has granted Fast Track designation for development of AV-101 as both a potential adjunctive treatment for major depressive disorder and as a non-opioid treatment for neuropathic pain.