Eirion Therapeutics Announces First-in-Human Trial Results for ET-02 in Androgenic Alopecia

After a slow and disappointing winter season in 2024, we start the year with some positive news in the androgenic alopecia space.

Eirion Therapeutics, a clinical-stage biopharmaceutical company with oral and topical androgenic alopecia treatments in the pipeline, has announced results from their 4-week androgenic alopecia trial of topical ET-02.

What Is ET-02?

We don’t know the exact mechanism of action of ET-02 other than what Eirion has said: “ET-02 has a novel mechanism of action which restores normal function to hair follicle stem cells that have become inactive in age-related hair loss due to a defect that develops in the stem cell biology.” We hope to hear more about this in the future as clinical studies progress. Eirion is also investigating ET-02 for reversing hair graying and an undisclosed indication. 

Trial Results

In the press release, Eirion gave details of the trial. The trial was a 4-week double-blind, placebo-controlled study of 24 participants with androgenic alopecia. Participants were split into three groups of equal size: placebo control, 1.25% ET-02, and 5% ET-02. The product was applied to the scalp once daily for 4 weeks, with a final assessment conducted one week later.

ET-02 was well-tolerated, and a dose-response effect was observed – the 5% dose led to “significant” improvement, whereas the 1.25% dose showed “minimal effect”. Therefore, the lower dose and the placebo were combined into one group for analysis. 

• The 5% ET-02 group showed a 6-fold increase in non-vellus hair count compared to the placebo group by week 5. 
• The 5% ET-02 group showed a 10% improvement in hair width compared to the placebo.

While Eirion is presenting this as a “potential breakthrough,” we see several issues with how this data has been presented:

• The dose-response results are vague, and the researchers use words like “minimal response” and “significant response,” which are qualitative. The press release lacks the numerical values or statistical data necessary to draw meaningful conclusions. 
• For the hair growth data, the placebo group’s absolute or relative change in non-vellus hair count is not provided, making it difficult to interpret the “6-fold increase” claim.
• In the press release, Eirion compares their results to a separate minoxidil trial, saying that ET-02 produced more non-vellus hair growth in one month than minoxidil did in four months. This is problematic as they don’t mention which minoxidil trial they are comparing to and only give the sample size, which is vastly different from the ET-02 trial. We don’t know what else is different about the trial, so we can’t really infer anything from this statement. The best way to compare to another product is to actually do a comparative study.  
• For the hair width data, the 10% improvement is ambiguous; we don’t know how it was measured, and we don’t have the placebo group data to determine what is being compared.

Reflections

We previously wrote about Eirion here and gave three questions that we would like answered: 

1. Efficacy: Will ET-02 prove to be significantly more effective than current treatments for androgenic alopecia in larger, more diverse populations?
2. Long-term Safety: What are the long-term safety implications of using ET-02, given its novel mechanism of action?
3. Broader Applications: Will ET-02 be effective in preventing or reversing hair greying by targeting melanocyte stem cells?

While they have not yet been answered, their future Phase 2 clinical trial, which will be 6 months long and include 150 people, should provide some information. 

Ultimately, the initiation of new research into hair loss treatments is a positive sign – and we should remember that this is a small first-in-human trial. We are looking forward to seeing what comes of later trials and hope that further data will be released so that we can interpret the results with more clarity.

Let us know what you think in the comments below.