Update: January 8, 2025

Eirion Therapeutics Announces Successful Results from Phase 1 Clinical Trials for ET-02

Eirion Therapeutics just announced the successful results of its first-in-man Phase1 clinical trial for the treatment of androgenic alopecia for its topical pharmaceutical drug ET-02. Per the press release, Phase 2 clinical trials with 150 participants will begin in 2025. They will measure safety and efficacy over a a 6-month treatment period.

• The trial was double-blind and placebo-controlled, and consisted of 24 subjects at 3 sites in the US. It divided these subjects into three groups who were treated once daily for 4 weeks with either: a control treatment consisting of the product vehicle; a 1.25% solution of ET-02; or a 5% solution of ET-02.
• 5% ET-02 resulted in a 6-fold increase in non-vellus hair count compared to the placebo group at the end of the fifth week of the trial.

I am not too excited as yet due to the small size of the study.

They also say the following, although I am not sure if “experimental graft model” equates to actual human scalp conditions:

“The net rate of hair growth produced by ET-02 in the fourth month of treatment was four times greater than the amount produced by minoxidil in a second, separate pre-clinical study using the same experimental graft model.”

September 29, 2024

I first mentioned privately-held Eirion Therapeutics (US) in a 2020 update in my post on reversing grey hair. In recent years, a number of people have discussed this company in the comments in this blog.

I was reluctant to write an entire post on Eirion (incepted in 2016) for various reasons:

• The company’s website is not SSL/https compliant. A rarity these days. Edit: It stopped working in December 2024, but then restarted working as an SSL compliant site.
• Its pipeline page link goes to a strange Wixsite. Edit: Corrected in January 2025.
• Its website has “Copyright 2021” at the bottom. Edit: Corrected in January 2025.
• Its news page had 0 updates in 2023 and 1 update in 2022.
• It had yet to commence Phase 1 Clinical trials.

However, the last point above changed on July 1, 2024 and I have now finally decided to write this post. Also of note, in 2021 Eirion raised $40 million in a Series A investment and licensing deal with Shanghai Haohai Biological Technology.

Historically, I have avoided writing posts on companies that are yet to commence clinical trials. Not that it makes much of a difference when it comes to my wasting of time. In almost all cases, companies that conduct successful initial trials for a hair loss product still never succeed in bringing it to market. Although this is now changing with the shortcut cosmeceutical-first approach (e.g., KX-826).

Eirion is working on oral and topical treatments for both androgenetic alopecia and hair greying. And in each case, for prevention as well as reversal. The topical product is called ET-02, and the oral product is called ET-03.

Eirion Therapeutics Begins Phase 1 Clinical Trial for Topical ET-02

ET-02 has a novel mechanism of action that works by converting defective or inactive hair follicle stem cells (in men suffering from pattern hair loss) to normal activity and function. ET-02 does not target hormonal pathways like finasteride or dutasteride, so no side effects are expected. For grey hair, ET-02 could reinvigorate melanocyte stem cells.

Coming back to the double-blind, placebo-controlled Phase 1 trials that Eirion initiated in the US in July 2024:

• 24 subjects will be recruited to test the safety of ET-02 for the treatment of androgenic alopecia.
• The once daily topical treatment will last for 28 days.
• According to company CEO Jon Edelson, ET-02 has the potential to not only treat androgenic alopecia, but also prevent it.

Besides hair loss and grey hair, Eirion Therapeutics is also developing products to treat wrinkles and primary axillary hyperhidrosis.

Plasminogen Activator Inhibitor-1 (PAI-1)

While Eirion Therapeutics’ products’ exact mechanism of action is not clear, there are some hints online.

Per a 2023 dated notice on Renascience (Japan)’s website, it says that in 2016, Renascience (Japan) executed an agreement with Eirion Therapeutics. It grants the latter an exclusive license to develop, manufacture and commercialize RS5441 (topical and oral) for the treatment of alopecia and other skin diseases. In the agreement it says the following:

“In a collaboration with Northwestern University, the company discovered that overexpression of plasminogen activator inhibitor (PAI)-1 is involved in alopecia, and that inhibition of PAI-1 activates hair matrix cells. In fact, genetically engineered mice that overexpress PAI-1 showed significant hair loss, and when the PAI-1 inhibitor RS5441 was administered to this model, significant hair growth was observed.”

Renascience’s pipeline page shows a few serious medical conditions that the company is attempting to treat with PAI-1 inhibitors. The company is not focusing on dermatological problems.

Also of note, Eirion CEO Jonathon Edelson has a patent to his name related to plasminogen activator inhibitor-1 inhibitors and their potential to treat and/or prevent certain dermatological conditions. The patent specifically points out the treatment and/or prevention of graying hair.

Nanoparticle Compositions to Treat Skin Conditions

Also of significance, Dr. Edelson and Eirion Chief R&D Officer Dr. Klaus Theobald are together names on several patents. A key one that was filed in 2011 and entails the use of nanoparticle compositions to treat skin conditions, including hair loss. More here.

The original patent was filed in 2012 by Anterios (which was taken over by Allergan in 2016), and two of the three inventors are listed as Mr. Edelson and Mr. Theobald.

In the hair loss section of the patent, it says the following:

“In some embodiments, provided compositions are useful for treating and/or preventing hair loss.”

“In some embodiments, provided compositions for treatment and/or prevention of hair loss are formulated into a cream, liniment, lotion, gel, shampoo, conditioner, etc.”

A sizable list of potential ingredients such as parabens, oil and sodium chloride is also mentioned, but nothing stands out.

Other patents that include Dr. Edelson as a co-inventor and potential hair growth application include ones on: nanoparticle based dermal delivery; and nanoparticle compositions that contain one or more peptides.