Research & Development
Vistagen Receives FDA "Study May Proceed" Letter Under its Investigational New Drug Application for PH10 to Treat Major Depressive Disorder
5 December 2022 - - US-based biopharmaceutical company Vistagen, (NASDAQ: VTGN) has received a "Study May Proceed" letter from the US Food and Drug Administration, the company said.

The letter greenlights a US Phase 1 clinical trial under Vistagen's newly filed Investigational New Drug application for clinical development of PH10 in the US as a standalone treatment for major depressive disorder.

The small Phase 1 trial will involve the company's newly optimized formulation of PH10 and is intended to both confirm the favorable safety profile of PH10 established in three previous clinical studies conducted in Mexico, including a published Phase 2A study for the treatment of MDD, and facilitate Vistagen's plans for Phase 2B development of PH10 as a stand-alone treatment for MDD.

At a 6.4 μg dose administered intranasally twice daily for 8 weeks, PH10 significantly reduced depressive symptoms as early as one week based on the 17-item Hamilton Depression Scale (HAM-D-17) scores compared to placebo (p = 0.022) in a small exploratory randomized, double-blind, placebo-controlled parallel design Phase 2A study in MDD.

PH10 was well-tolerated and did not cause psychological side effects (such as dissociation or hallucinations) or other safety concerns that may be associated with other approved pharmacological therapies for MDD.

More information about the PH10 Phase 2A study in MDD can be found in the peer-reviewed article, A Placebo Controlled Trial of PH10: Test of a New Rapidly Acting Intranasally Administered Antidepressant, published in the November-December 2019 edition of the British Journal of Pharmaceutical and Medical Research.

PH10 is an investigational pherine nasal spray designed with a potential rapid-onset mechanism of action that is fundamentally differentiated from the MOA of all currently approved treatments for depression disorders.

PH10, which is administered at microgram-level doses, engages and activates chemosensory neurons in the nasal passages, connected to neural circuits in the brain that produce antidepressant effects.

Specifically, PH10's proposed MOA involves binding to receptors for chemosensory neurons in the nasal passages to regulate the olfactory amygdala "fear on" neural circuits believed to increase activity of the limbic-hypothalamic sympathetic nervous system and increase the release of catecholamines.

Importantly, unlike all currently approved oral antidepressants and rapid-onset ketamine-based therapy, including both intravenous ketamine and intranasal ketamine (esketamine), we believe PH10 does not require systemic uptake to produce rapid-onset of antidepressant effects and does not cause the side effects and safety concerns potentially associated with rapid-onset KBT.

Vistagen (NASDAQ: VTGN) is a late clinical-stage biopharmaceutical company aiming to transform the treatment landscape for individuals living with anxiety, depression and other CNS disorders.

The company is advancing therapeutics with the potential to be faster-acting, and with fewer side effects and safety concerns, than those that are currently available. Vistagen's clinical-stage candidates are targeting multiple forms of anxiety and depression.

PH94B and PH10 belong to a new class of drugs known as pherines, which are odorless and tasteless investigational neuroactive steroids designed with a novel rapid-onset mechanism of action that activates chemosensory neurons in the nasal passages and can impact the olfactory-amygdala neural circuits without systemic uptake or direct activity on CNS neurons in the brain.

Vistagen is passionate about transforming mental health care and redefining what is possible in the treatment of anxiety and depression.