GSK is presenting the clinical trial results for dabrafenib and trametinib today at the annual conference of the American Society of Clinical Oncology, or ASCO. The phase 3 data for trametinib were also published online in the New England Journal of Medicine.
The drugs were studied in melanoma patients with expressed mutations on the BRAF gene. Dabrafenib is a BRAF inhibitor. Trametinib is an inhibitor of the MEK protein. Patients studied with both drug candidates showed statistically significant benefit in how long they lived without their disease progressing — progression-free survival — compared to those patients receiving chemotherapy. In the study of trametinib, patients who received that GSK compound showed longer overall survival than those who received chemotherapy with dacarbazine, a cancer drug used to treat melanoma. Overall survival data for dabrafenib are not yet ready.
Dr. Rafael Amado, head of oncology R&D for GSK, said that trametinib is the first MEK inhibitor to demonstrate clinical benefit in a late-phase melanoma trial.
Besides studying dabrafenib and trametinib as separate cancer drugs, GSK is also studying the compounds in combination. The British pharmaceutical company, which has its U.S. headquarters in Research Triangle Park, North Carolina, last week announced the start of a phase 3 trial that will evaluate the combination drug against a placebo as well as head-to-head against Roche’s BRAF inhibitor vemurafenib, marketed as Zelboraf. Amado previously said that tumors become resistant to inhibitors. GSK believes the combination of a MEK inhibitor with a BRAF inhibitor may delay that resistance.
[Photo from wikipedia]