Mitogen-activated protein kinase (MEK) inhibitors to treat melanoma alone or in combination with other kinase inhibitors

Introduction: Malignant melanoma (MM) is an aggressive disease with a rapidly rising incidence due to neoplasm of melanocytes. Molecular targeted therapies have demonstrated lower toxicity and improved overall survival versus conventional therapies of MM. The revealing of mutations in the BRAF/MEK/ERK pathway has led to the development of BRAF inhibitors such as vemurafenib and dabrafenib for the treatment of cutaneous MM. Though, progression of resistance to these agents has prompted attempts to target downstream proteins in this pathway. Trametinib, a MEK1/2 inhibitor, was approved in 2013 for the treatment of BRAF V600E/K mutation-positive unresectable or metastatic cutaneous melanoma patients. Areas covered: The aim of the current review is to present an update on the role of MEK in progressive melanomas and summarize latest results of clinical studies with innovative MEK inhibitors and/or combined approaches with other kinase inhibitors such as BRAF inhibitors in the treatment of MM. Expert opinion: Two combined treatments (i.e. trametinib plus dabrafenib and vemurafenib plus cobimetinib) target two different kinases in the BRAF/MEK/ERK pathway. The simultaneous prohibition of both MEK and BRAF is associated with more durable response rate than BRAF monotherapy and can overcome acquired resistance.