Evaluation of Photosensitivity in Dabrafenib or Vemurafenib Treated Metastatic Melanoma Patients - a Phase IIa/IIb Study

The BRAF inhibitors dabrafenib and vemurafenib belong both two a new class of potent anti-cancer drugs and are highly efficacious in tumors harboring the BRAF V600E mutation. Both drugs seem to be equally efficacious; however, their toxicity profile seems to differ. Serious phototoxicity has been observed in \~ 30% of patients treated with vemurafenib and in \~2 percent of patients treated with dabrafenib. These phototoxic reactions have developed in spite of informing the patients of this possible adverse event and instructing them to protect themselves. Manifestation of phototoxic reactions depends on the patient's habits of exposure and their efforts to protect themselves. The true frequency of photosensitivity can only be established by systematic photo-testing. In dermatology, standard test procedures with different UV-wavelengths and dosages have been established and the primary goal of this study will be to clarify the true rate of photosensitivity by these two BRAF-inhibitors. Furthermore, systematic experience will be collected how to best protect patients from phototoxic events. Dabrafenib and Vemurafenib are commercially available and considered standard of care for BRAF mutant metastatic melanoma in Germany. As the number of patients will not allow any conclusion with regard to efficacy or safety of vemurafenib, patients randomized to vemurafenib in part 2 will only remain on study until completion of phototesting.