B2.4 Pattern alopecia: What clinical features determine the response to topical minoxidil treatment?

Jan Rundegren

Pfizer Consumer Healthcare, Helsingborg, Sweden

Objectives: It is generally known that the individual response to treatment with drugs can vary substantially. It is wishful to be able to predict individual treatment effects not only from a treatment success point of view but also from economical and compliance aspects of the treatment. In the present review clinical features of men and women treated with topical minoxidil (mnx) solutions were analyzed with the aim to identify clinical predictors of treatment response.

Methods: Post-hoc analyses of clinical trial data in 636 males (2% mnx) and 630 females (2 and 5% mnx) were made. For males a therapeutic benefit was compared to age, duration of balding, and diameter of balding vertex area. For females therapeutic benefit was compared to age and duration of hair loss. Post-marketing data obtained from more than 660 male patient questionnaires were analyzed for treatment effects (5% mnx) in relation to duration of alopecia.

Results: Age was found to be the best denominator for predicting treatment success for both males and females. Thus the younger subjects experienced better efficacy than the older subjects although clear treatment effects were noted also in the older age group. Males showed an inverse relationship between effect and duration of balding. Thus males with duration of balding <5 years showed a significantly better effect than those with duration of balding >21 years (p=0.0043). Females, on the contrary, showed no correlation between effect and duration of balding. It is speculated that because females have a more diffuse type of pattern alopecia or hair thinning it might be difficult for them to identify the starting time for alopecia, whereas for males the vertex balding would be more easily recognized by the subject himself or by family members. The diameter of the vertex balding in men showed an inverse relationship with efficacy of minoxidil. Thus males with less than a 5 cm diameter vertex balding area showed a better effect of treatment than subjects with larger diameters (>15 cm) of vertex balding (p=0.0180). The post-marketing data showed that duration of hair loss less than one year compared to more than 10 years at onset of treatment resulted in a significantly more effective treatment with regard to stabilization of alopecia and new hair growth (p=0.0050 and p=0.0005 respectively).

Conclusion: It is possible to use clinical features to predict minoxidil treatment response both in males and females. It may be difficult for females to self-diagnose the subtle changes that occur in the early stages of their pattern alopecia.