Results are encouraging in an ongoing clinical trial of a BRAF inhibitor combined with a MEK inhibitor, according to a presentation at the 2013 European Cancer Congress in Amsterdam, Netherlands. The BRAF inhibitor is vemurafenib, which is approved by the U.S. Food and Drug Administration (FDA), and the MEK inhibitor is cobimetinib (GDC-0973/XL518), which is experimental. The phase I trial has 128 people with melanomas that have BRAFV600 mutations; about half had been treated with BRAF inhibitors previously, while the other half had not. Tumors shrank in 15% of participants and didn't grow in 43% of those who had been previously treated with BRAF inhibitors. Even better, tumors disappeared in 10%, shrank in 75%, and didn't grow in 13% of those who had not been previously treated with BRAF inhibitors.