For the first time, the FDA approved a combination therapy for melanoma. The treatment, which is marketed by GlaxoSmithKline, consists of Dabrafenib (Tanfinlar) and Trametinib (Mekinist). As stand-alone treatments, each drug received their single treatment approval from the FDA in 2013 for use in the treatment of metastatic or unresectable melanoma. The drugs are prescribed with the confirmation of a companion diagnostic test and can only be used on patients with the BRAF V600E or the V600K melanoma mutation.
The combination therapy will stand to serve many patients as at least 50% of modern melanoma diagnoses represent one of the two mutations. Dabrafenib is used to treat the BRAF V600E strain as an inhibitor, while Trametinib is referred to as a MEK inhibitor that primarily targets both strains.
The deciding factor in the approval of the combination therapy was discovered when an open-label, phase II trial was performed with the intention off comparing both drugs as a unit against Dabrafenib by itself. The results were conclusive of a significant advantage if treatment was performed as a combination therapy. The response rate was 74% in comparison to a stand-alone Dabrafenib treatment with a response rate of just 54%.
The new combination therapy, however, is not void of risk. Both methods of treatment involved an excess of secondary skin cancers, with the combination therapy leading the risk of basal cell carcinoma by 9%. The stand-alone Dabrafenib treatment presented a risk rate of 2% for basal cell carcinoma, but it caused more cutaneous cell carcinoma and keratoacanthoma.
The FDA approval of the combination therapy remains dependant on the results of a phase III clinical trial that is currently in the works, and is testing the combination therapy as a first-line therapy for melanoma. The clinical trial is also comparing the combination therapy against a Dabrafenib placebo.