High efficacy of red light photodynamic therapy with 10% aminolevulinic acid gel irrespective of the extent of keratinocyte atypia in actinic keratosis – exploratory post-hoc analysis of three pivotal phase III trials

Primary endpoints of clinical studies investigating treatments for actinic keratosis (AK) are mainly based on clinical evaluation, but a recent study showed that in AK, clinical classification according to Olsen and the extent of keratinocyte atypia do not necessarily correlate. The influence of the epidermal extent of atypia on treatment efficacy is usually not investigated and therefore remains largely unknown.