Vistagen announced that it has received a “study may proceed” letter from the FDA in response to the company’s IND for a Phase 2 trial of refisolone nasal spray for the treatment of hot flashes caused by menopause. In 2023, the company announced results from a Phase 2a study of the nasal spray (PH80) for the treatment of hot flashes in menopausal women that was conducted prior to Vistagen’s acquisition of PH80 when it acquired Pherin Pharmaceuticals.
According to Vistagen, “Refisolone is administered intranasally at microgram-level doses to rapidly activate chemosensory neurons in the nasal cavity, which engage olfactory–limbic and olfactory–hypothalamic pathways that modulate anxiety and thermoregulatory neural circuits.” The company also has been granted a number of patents related to the use of PH80 nasal spray for the treatment of migraine.
In December 2025, Vistagen announced that a Phase 3 trial of fasendiol (PH94b) for the treatment of social anxiety, another intranasal pherine acquired along with Pherin Pharmaceuticals, had failed to meet its primary endpoint. The company’s pipeline also includes itruvone (PH10) nasal spray, which the company is developing for the treatment of major depressive disorder.
Vistagen President and CEO Shawn Singh commented, “This regulatory milestone marks another important step forward in our women’s health program for refisolone. Approximately 75% of all women in America experience hot flashes during their menopausal transition, yet there is a critical need for new treatment options. As demonstrated in exploratory Phase 2a clinical data, refisolone has the potential to advance women’s health and bring a fast-acting, non-hormonal treatment option for millions of women seeking relief from menopausal hot flashes.”
Read the Vistagen press release
