Pyrilutamide: A New Hope for Hair Loss Treatment
What is Pyrilutamide?
Pyrilutamide, also known as KX-826, is a topical drug that belongs to the class of nonsteroidal antiandrogens (NSAAs). NSAAs work by blocking the action of androgens, such as testosterone and dihydrotestosterone (DHT), on the androgen receptor (AR) in target tissues. Androgens are male hormones that play a role in various physiological processes, such as sexual development, muscle growth, and hair growth. However, excessive androgen activity can also cause unwanted effects, such as acne, prostate enlargement, and androgenetic alopecia (AGA), or pattern hair loss
AGA is the most common form of hair loss in both men and women. It is characterized by a progressive thinning and receding of the hairline, especially at the temples and crown of the head. AGA is caused by a genetic predisposition and hormonal factors, mainly DHT. DHT is a more potent form of testosterone that binds to the AR in hair follicles and triggers a process called miniaturization. This means that the hair follicles shrink over time and produce shorter, finer, and lighter hairs, until they eventually stop growing altogether
Pyrilutamide aims to prevent or reverse this process by inhibiting the binding of DHT to the AR in hair follicles. By doing so, it may protect the hair follicles from the harmful effects of DHT and stimulate hair growth.
How Effective is Pyrilutamide?
Pyrilutamide is currently under development by Kintor Pharmaceutical Ltd., a biotechnology company based in China. It has successfully completed phase II clinical trials in China for the treatment of AGA in men and women, and phase II clinical trials in the United States for the treatment of AGA in men. It is also being tested as a potential treatment for acne vulgaris, another condition related to excessive androgen activity
According to the results of the phase II clinical trials in China, pyrilutamide showed good efficacy and safety in treating AGA in both genders. The trials involved 120 men and 120 women with moderate AGA symptoms, who were randomly assigned to receive either pyrilutamide 0.5% gel or placebo gel twice daily for 24 weeks. The primary endpoint was the change from baseline in non-vellus target area hair count (TAHC) at week 24. The secondary endpoints included changes in hair density, hair diameter, global photographic assessment (GPA), patient self-assessment (PSA), investigator global assessment (IGA), quality of life (QoL), and safety parameters
The results showed that pyrilutamide significantly increased TAHC by 18.4 hairs/cm2 in men and 16.9 hairs/cm2 in women, compared to placebo, which increased TAHC by 6.8 hairs/cm2 in men and 5.9 hairs/cm2 in women. Pyrilutamide also improved hair density, hair diameter, GPA, PSA, IGA, and QoL scores in both genders, compared to placebo. Pyrilutamide was generally well-tolerated, with no serious adverse events reported. The most common adverse event was contact dermatitis, which occurred in 8% of men and 6% of women who used pyrilutamide, compared to 2% of men and 1% of women who used placebo
The results of the phase II clinical trial in the United States have not been published yet, but according to Kintor’s website, they are expected to be announced soon. The trial involved 240 men with moderate AGA symptoms, who were randomly assigned to receive either pyrilutamide 0.5% gel or placebo gel twice daily for 24 weeks. The primary endpoint was the change from baseline in TAHC at week 24. The secondary endpoints were similar to those of the Chinese trials
How Does Pyrilutamide Compare to Other Hair Loss Treatments?
Currently, there are only two FDA-approved drugs for the treatment of AGA: minoxidil and finasteride. Minoxidil is a topical solution or foam that stimulates blood flow to the scalp and prolongs the growth phase of the hair cycle. Finasteride is an oral tablet that inhibits the enzyme 5-alpha-reductase, which converts testosterone into DHT. Both drugs have been shown to slow down or stop hair loss and promote hair regrowth in some patients with AGA. However, they also have some limitations and drawbacks.
Minoxidil has to be applied twice daily to the scalp and may take several months to show any effect. It may cause scalp irritation, itching, dryness, and flaking. It may also cause unwanted hair growth on other parts of the body, such as the face, chest, and back. Minoxidil is not very effective in treating frontal hair loss or receding hairline. It also does not address the underlying cause of AGA, which is DHT. Therefore, if minoxidil is discontinued, the hair loss will resume.
Finasteride has to be taken once daily by mouth and may take several months to show any effect. It may cause sexual side effects, such as decreased libido, erectile dysfunction, and ejaculation disorders. It may also increase the risk of prostate cancer, breast cancer, and depression. Finasteride is not approved for use in women, especially those who are pregnant or may become pregnant, as it may cause birth defects in male fetuses. Finasteride also does not address the local action of DHT on the hair follicles. Therefore, if finasteride is discontinued, the hair loss will resume.
Pyrilutamide may offer some advantages over minoxidil and finasteride as a hair loss treatment. Pyrilutamide is a topical gel that can be easily applied to the scalp once or twice daily. It may have a faster onset of action than minoxidil and finasteride, as it directly blocks the binding of DHT to the AR in hair follicles. It may be more effective in treating frontal hair loss or receding hairline than minoxidil, as it targets the most sensitive areas to DHT. It may have fewer systemic side effects than finasteride, as it has a low absorption rate and a short half-life in the blood. It may also be suitable for use in both men and women with AGA
However, pyrilutamide is not without its limitations and drawbacks. Pyrilutamide has not been approved by the FDA or any other regulatory agency for the treatment of AGA or any other condition. It is still in the late stages of clinical development and its long-term safety and efficacy have not been established yet. Pyrilutamide may cause contact dermatitis or skin irritation in some users, especially those with sensitive skin or allergies. Pyrilutamide may also interact with other drugs that affect the AR, such as steroids, antiandrogens, or hormone replacement therapy. Pyrilutamide may not work for everyone with AGA, as there may be other factors involved in hair loss besides DHT
Conclusion
Pyrilutamide is a promising new drug for the treatment of AGA that works by blocking the action of DHT on the AR in hair follicles. It has shown good efficacy and safety in phase II clinical trials in China for both men and women with AGA, and is currently undergoing phase III clinical trials in China and phase II clinical trials in the United States for men with AGA. Pyrilutamide may have some advantages over existing hair loss treatments, such as minoxidil and finasteride, but it also has some limitations and drawbacks that need to be further investigated. Pyrilutamide is not yet available for commercial use and its long-term safety and efficacy are still unknown. Therefore, anyone interested in trying pyrilutamide should consult their doctor before using it.