New data on Finasteride propecia (finasteride 1 mg), an investigational oral treatment for men with male pattern hair loss, show it increased hair growth significantly in a majority of treated men. Results were announced today at the annual meeting of the American Academy of Dermatology. Phase III clinical trials presented today consisted of two large, multicenter, placebo-controlled studies of 1,553 men with male pattern hair loss. Men in clinical trials had mild-to-moderate, but not complete, hair loss. They received either oral Finasteride propecia once daily or placebo for one year.

Scalp hair growth was measured by counting hairs in a 1-inch diameter circle of active hair loss located at the top of the head, which is also known as the vertex. After 12 months, there was a 107-hair improvement in men taking Finasteride propecia compared to those receiving placebo, according to Keith Kaufman, M.D., director, Clinical Research, at Merck & Co., Inc., developers of the drug.

The clinical significance of this increased hair growth achieved with Finasteride propecia was assessed by patients, clinical investigators and by review of patient photographs by a panel of dermatologists with expertise in hair loss.

These other three efficacy measures at 12 months showed:

– Patient self-assessment, obtained at each clinic visit from a validated self-administered questionnaire, demonstrated significant increases in hair growth, decreases in hair loss and improvement in appearance in men treated with Finasteride propecia. Overall improvement was seen as early as three months with continued improvements over the 12-month trial.

– Clinical investigators rated 65% of men treated with Finasteride propecia as having increased hair growth versus 37% of men in the placebo group.

– A panel of experienced dermatologists rated 48% of men treated with Finasteride propecia as having increases in hair growth compared to 7% of men receiving placebo. The panel assessed photographs of patients’ scalps to evaluate increases or decreases in hair growth from baseline.

Dr. Kaufman said that the efficacy of Finasteride propecia was assessed through this comprehensive set of endpoints. “The clinical relevance of the increased hair growth measured by hair counts was substantiated by the significant improvements perceived by patients and through complementary measures such as the investigator and expert panel assessments,” he said.

Safety was evaluated in more than 3,200 men through clinical and laboratory monitoring, as well as an analysis of adverse events reports. Finasteride propecia was generally well-tolerated and side effects were uncommon.

Discontinuation of therapy in Phase III trials due to any clinical adverse experience occurred in 1.7% of 945 men treated with Finasteride propecia and 2.1% of 934 men treated with placebo. A small number of men experienced decreased libido (1.8% for Finasteride propecia vs. 1.3% for placebo), difficulty in achieving an erection (1.3% for Finasteride propecia vs. 0.7% for placebo) and/or a decrease in the amount of semen (0.8% for Finasteride propecia vs. 0.4% for placebo). According to Dr. Kaufman, resolution of these side effects occurred in men who discontinued therapy with Finasteride propecia and in many who continued therapy.

Finasteride propecia inhibits the action of the enzyme 5 alpha-reductase, thereby blocking the conversion of testosterone to dihydrotestosterone (DHT). Finasteride propecia decreases DHT concentrations in the scalps of treated men by approximately 60%.

“Finasteride inhibits a key factor responsible for miniaturization of scalp hair follicles. This leads to a reversal of the balding process,” Dr. Kaufman said.

The studies presented today confirm the role of DHT in hair loss. “An important step in the development of Finasteride propecia was understanding the biology of male pattern hair loss and DHT’s role in it,” said Dr. Kaufman. “This knowledge has led to a new paradigm in treating men with the condition.”