Clinical studies in dermatology require a post-treatment observation phase to define the impact of the intervention on the natural history of the complaint

Abstract

The use of a post-treatment period of observation or “regression phase” is common in pharmaceutical and cosmetic clinical dermatology studies. Regression phases can be incorporated into a variety of study designs, ranging from simple post-treatment observation for a defined period, as has been used for moisturizers, antidandruff formulations, and treatments for acne, to more complex randomized intermittent-treatment designs, as used in studies of psoriasis pharmacotherapies. Extensive information can be derived from a regression phase. Notably, it can provide useful data on the persistence of effect and time to relapse after treatment cessation, which are particularly relevant to skin condit..