PDT With Metvix 160 mg/g Cream Versus PDT With Placebo Cream in Patients With Primary Nodular Basal Call Carcinoma

Photodynamic therapy (PDT) is the selective destruction of abnormal cells through light activation of a photosensitiser in the presence of oxygen. These cells accumulate more photosensitiser than normal cells. The photosensitiser generates reactive oxygen species upon illumination. For skin diseases, there has been an increasing interest in using precursors of the endogenous photosensitiser protoporphyrin IX (PpIX). The most commonly used precursors have been 5-aminolevulinic acid (ALA) and its derivatives. The present test drug, Metvix®, contains the methyl ester of ALA, which penetrates the lesions well and shows high lesion selectivity . In vitro studies of animal and human tissues have shown significant intracellular formation of photoactive porphyrins after addition of Metvix®. The increased levels of photoactive porphyrins induced cytotoxic effects in tumour cells after photoactivation. The primary objective is to compare PDT with Metvix® cream to PDT with placebo cream in terms of patient complete response rates based on histologically verified disappearance of the lesions at 6 months after last treatment cycle. Secondary objectives are to compare the two treatments in terms of histological and clinical mean patient response weighted by the number of lesions within a patient, lesion response rates across patients, clinical complete patient response, cosmetic outcome and adverse events.