Protein kinase inhibitors in melanoma

The most commonly mutated oncogene identified to date in melanoma is BRAF (∼ 50%), an upstream mediator of the mitogen-activated protein kinase (MAPK) pathway. Recently, BRAF-kinase inhibitors as well as MEK-kinase inhibitors were introduced into the clinics.

Substantial Phase II and III clinical trials were searched in patients with advanced melanoma treated with BRAF-kinase inhibitors, MEK-kinase inhibitors and cKIT inhibitors.

For patients with a BRAF, NRAS or cKIT mutation the treatment with selective, targeted drugs is considered as feasible and results in a high rate of confirmed tumor responses. In patients with BRAF mutation the progression free survival and overall survival is prolonged in patients who were treated with BRAF kinase inhibitors or MEK kinase inhibitors compared to patients receiving chemotherapy with dacarbazine. A major problem is the development of resistance to the inhibitors through multiple different mechanisms. One approach to overcome resistance is to combine BRAF and MEK inhibitors. Treatments with kinase inhibitors are more efficacious than chemotherapies, however, they compete with the newly developed immune checkpoint blockers, and may in future be preferentially applied in second- or x-line.