Finasteride in the treatment of men with androgenetic alopecia,☆☆

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Abstract

Background: Androgenetic alopecia (male pattern hair loss) is caused by androgen-dependent miniaturization of scalp hair follicles, with scalp dihydrotestosterone (DHT) implicated as a contributing cause. Finasteride, an inhibitor of type II 5α-reductase, decreases serum and scalp DHT by inhibiting conversion of testosterone to DHT. Objective: Our purpose was to determine whether finasteride treatment leads to clinical improvement in men with male pattern hair loss. Methods: In two 1-year trials, 1553 men (18 to 41 years of age) with male pattern hair loss received oral finasteride 1 mg/d or placebo, and 1215 men continued in blinded extension studies for a second year. Efficacy was evaluated by scalp hair counts, patient and investigator assessments, and review of photographs by an expert panel. Results: Finasteride treatment improved scalp hair by all evaluation techniques at 1 and 2 years (P < .001 vs placebo, all comparisons). Clinically significant increases in hair count (baseline = 876 hairs), measured in a 1-inch diameter circular area (5.1 cm2 ) of balding vertex scalp, were observed with finasteride treatment (107 and 138 hairs vs placebo at 1 and 2 years, respectively; P < .001). Treatment with placebo resulted in progressive hair loss. Patients’ self-assessment demonstrated that finasteride treatment slowed hair loss, increased hair growth, and improved appearance of hair. These improvements were corroborated by investigator assessments and assessments of photographs. Adverse effects were minimal. Conclusion: In men with male pattern hair loss, finasteride 1 mg/d slowed the progression of hair loss and increased hair growth in clinical trials over 2 years. (J Am Acad Dermatol 1998;39:578-89.)

Section snippets

Study population (Tables IA and IB)

Table IA. Baseline characteristics of men randomized in initial studies

Empty CellUS phase III initial studyInternational phase III initial study
Finasteride 1 mg (n = 471)Placebo (n = 462)Finasteride 1 mg (n = 308)Placebo (n = 312)
Age (y, mean ± SE)33 ± 0.234 ± 0.231 ± 0.331 ± 0.3
Age at which hair loss began (y, mean ± SE)24 ± 0.225 ± 0.224 ± 0.324 ± 0.3
No. (%) of patients with family history*373 (80)363 (80)227 (74)239 (77)
Baseline hair count (mean ± SE)864 ± 11856 ± 12916 ± 15924 ± 14
No. (%) of

EVALUATION PROCEDURES

Four predefined efficacy end points provided a comprehensive assessment of changes in scalp hair from baseline.

LABORATORY EVALUATION

Hematology, urinalysis, chemistry, and hormone measurements were performed at baseline and every 6 months. Serum chemistry, including prostate-specific antigen (PSA), and serum hormones, including testosterone, DHT, luteinizing hormone, and follicle-stimulating hormone, were assayed in central laboratories (Medical Research Laboratories, Highland Heights, Ky, and Endocrine Sciences, Calabasas Hills, Calif, respectively).

STATISTICAL ANALYSIS

A data analysis plan prespecified all primary and secondary hypotheses, including combining data from both initial studies, to improve precision of the estimates of treatment effect, and from both extension studies, because of the small size of the placebo groups in the extension phase.

The primary hypothesis for hair counts was assessed by the difference between the count at each time point and the accompanying baseline count, and mean values for each treatment group were determined by means of

RESULTS

Patient accounting is summarized in Fig 1.

ADVERSE EVENTS

Clinical adverse events considered by the investigator to be possibly, probably, or definitely drug-related that occurred in 1% of men or more are shown in Table IV. In the first year, a slightly higher proportion of finasteride-treated than placebo-treated patients reported adverse events related to sexual function (4.2% vs 2.2%, P < .05; see Table IV for details). Only 11 men (1.4%) in the finasteride group and 8 (1.0%) in the placebo group discontinued the study because of sexual adverse

DISCUSSION

In these studies, finasteride treatment produced significant improvements in scalp hair in men with male pattern hair loss. The efficacy of finasteride was evident within 3 months of therapy. Hair count, first measured at 6 months, progressively increased over 1 year in the finasteride group, and the improvement was maintained through the second year. In contrast, the placebo group progressively lost hair, consistent with the miniaturization process and the natural history of male pattern hair

Acknowledgements

We acknowledge the technical assistance of Mr. Douglas Canfield, of Canfield Scientific, Inc, in the development of photographic procedures used in these clinical studies. We also thank Dr O’Tar Norwood for permission to use drawings in the clinical study protocols that first appeared in his article “Male Pattern Baldness: Classification and Incidence” (South Med J 1975;68:1359-65).

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    *

    The Finasteride Male Pattern Hair Loss Study Group includes (in alphabetical order) R. Asarch, N. Birchall, I. H. Boersma, S. Brenner, K. Bruno, D. Buntin, G. Burg, J. Cilliers, P. Cotterill, W. J. Cunliffe, D. Ferguson, V. Fiedler, D. Fivenson, T. Funicella, C. Gencheff, D. Gratton, W. He, S. Horwitz, J. Imperato-McGinley, F. Jurado Santa-Cruz, I. Katz, A. P. Kelly, D. Kopera, P. Kotey, J.-M. Lachapelle, M. Ling, E. Lopez-Bran, N. Lowe, A. Lucky, S. MacDonald Hull, A. McDonagh, C. Mork, G. Peck, E. Prens, P. Reygagne, R. Rietschel, R. Rittmaster, E. Round, T. Rufli, N. Sadick, P. Saiag, P. Sanchez-Pedreno, J. B. Schmidt, M. Sher, J. Shupack, D. Steiner, D. Stewart, M. Stiller, D. Stough, J. Swinehart, L. Swinyer, G. Todd, W. Unger, J. Waldstreicher, G. Weinstein, D. Weiss, J. Weiss, S. E. Whitmore, and H. Wolff.

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