Hair growth has three stages: growth, catagen where hair grows, and telogen where hair falls out. Androgenic alopecia (AGA) is a condition in which the hair growth phase shortens and the hair follicles (the tissue that surrounds the hair root and allows it to grow) remain in the telogen phase more frequently during the hair cycle. Hair on the forehead and top of the head becomes soft, thin, and short, eventually leading to baldness. In Japanese men, the condition gradually progresses from the late 20s, and by the age of 50 or older, the proportion of men with male pattern baldness is over 40 %. Genetics and male hormones are involved in the development of male pattern baldness.

Our pharmaceutical products (RS5441)

PAI-1 expression is increased in the scalp of human AGA, and mice that overexpress PAI-1 do not grow hair. RS5441 showed a clear hair growth effect in these mice. Based on these research results, we signed a license agreement with Eirion, Inc. of the United States on October 31, 2016 to commercialize this drug.

Progress to date

Eirion, the licensee, has obtained the following results to date.

Pre-clinical study

In a pre-clinical trial, in which 60 scalp tissue grafts from patients with AGA were exposed to a 5 % solution of ET-02 (active Ingredient RS5441), the hair growth rate four months after treatment with ET-02 was four times higher than the hair growth rate of the standard treatment minoxidil (n=103) using the same experimental graft model.

Phase I clinical trial

On July 1, 2024, a Phase I clinical trial was initiated to evaluate the safety and efficacy of topical ET-02 for the treatment of male pattern baldness (age-related alopecia). The double-blind, placebo-controlled study consisted of either placebo, 1.25 % or 5 % solution of ET-02 (once daily for 28 days) in 24 subjects at three US medical centers.

• Safety: ET-02 was safe and well tolerated.
• Dose-response: Significant responses were observed in the high-dose 5% ET-02 group, whereas minimal responses were observed in the 1.25% ET-02 group. Therefore, the placebo group was combined with the 1.25% ET-02 dose group in the analysis.
• Hair growth: The 5 % ET-02 group had a six-fold increase in non-vellus (or normal) hair count compared to the placebo group at the end of the fifth week. After one month of treatment, 5 % ET-02 showed more non-vellus hair growth than topical minoxidil after four months of treatment as measured in a separate clinical trial of minoxidil, a treatment for male pattern baldness.
• Hair thickness: Improved non-vellus hair thickness by approximately 10 points compared to the placebo group, which had essentially no change, whereas the placebo group had essentially no change.

Phase I clinical trial results substantiate the efficacy of 5 % ET-02 as confirmed in pre-clinical trials. Erion is preparing for a phase II clinical trial (n=150) aimed at confirming the safety and efficacy of ET-02.