Development of Cutaneous Toxicities During Selective Anti-BRAF Therapies: Preventive Role of Combination with MEK Inhibitors

Abstract

Activated BRAF mutations affecting the mitogen-activated protein kinases (MAPK) pathway are present in 50% of metastatic melanomas. Targeted therapies have been developed to block such mutations (1, 2). There is a risk of other components of the MAPK signalling pathway, such as MEK, being reactivated after the use of BRAF inhibitors (3-5). Given the evidence of drug resistance and side-effects of BRAF inhibitors, combined treatments with BRAF and MEK inhibitors are being tested in clinical trials for metastatic melanoma. Trametinib is one of these MEK inhibitors. Skin toxicities from BRAF inhibitors, such as photosensitivity, palmoplantar keratoderma (PPK) and keratosis pilaris (KP), have been reported (4, 6-11). Also, non-melanoma skin cancers (NMSC) are considered one of the most significant sideeffects (3, 11). We report here the profile of skin toxicities from vemurafenib, dabrafenib alone, or dabrafenib and trametinib combined treatment.