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| Other names | KX-826 |
| Routes of administration | Topical |
| Drug class | Nonsteroidal antiandrogen |
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| Chemical and physical data | |
| Formula | C21H15F5N4O2S |
| Molar mass | 482.43 g·mol−1 |
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Pyrilutamide (developmental code nameKX-826) is anonsteroidal antiandrogen (NSAA) – specifically, aselective high-affinitysilentantagonist of theandrogen receptor (AR) – which is under development by Suzhou Kintor Pharmaceuticals, inc., a subsidiary of Kintor Pharmaceutical Limited, for the potential treatment ofandrogenic alopecia (androgen-dependent scalp hair loss)[2][3][4] As of September 2022, it is inphase 3clinical trials for androgenic alopecia andphase 2 trials for acne.[3]
Pyrilutamide has undergone several clinical trials for the treatment of androgenic alopecia (AGA) in both males and females.[5] The primary endpoint for most trials was the change from baseline in non-vellus target area hair count (TAHC) compared to placebo after 24 weeks of treatment.[5]
A phase II trial in China enrolled 120 male patients, randomized into four groups: KX-826 0.25% BID (twice daily), KX-826 0.5% QD (once daily), KX-826 0.5% BID, and placebo. After 24 weeks, the 0.5% BID group showed significant improvement:[5]
A phase II trial for female AGA in China included 160 patients in five groups: KX-826 0.25% QD, 0.25% BID, 0.5% QD, 0.5% BID, and placebo. After 24 weeks:[5]
A phase II trial in the U.S. enrolled 123 male patients, divided into KX-826 0.25% QD, 0.5% QD, 0.5% BID, and placebo groups. Results after 24 weeks showed:[5]
A phase III trial for male AGA in China enrolled 740 patients, randomized into KX-826 0.5% BID and placebo groups. Results announced on November 27, 2023, showed:[5]
In addition to its ongoing clinical development, Pyrilutamide has been introduced to the market as a cosmetic anti-hair loss product under the brand name Koshine. This approach allows it to be made available to consumers without the need for full regulatory approval as a medical treatment. Its classification as a cosmetic reflects a strategic decision to facilitate earlier access while formal medical approval is still pending.[6]
Pyrilutamide is generally well-tolerated. The most common adverse event iscontact dermatitis.[7]
Across all trials, KX-826 demonstrated a favorable safety profile:[5]
Pyrilutamide binds to the androgen receptor with a very high affinity with anIC50 of 0.28 nM.[4] Reference drugbicalutamide had an IC50 of 3.1 nM.[4]