Eight out of 10 melanomas with V600E mutation respond to new drug

PLX4032 has been shown in animal studies to stop the growth of melanoma cells, but only when the target oncogene, which encodes the enzyme serine-threonine protein kinase B-RAF, has the V600E mutation (valine substituted for glutamic acid at amino acid 600). A phase I dose escalation trial has found the maximum dose at which side effects such as rash, fatigue, and joint pain occur in fewer than one in six people. Most participants had metastatic melanoma, three had papillary thyroid cancer, and three had other cancers, regardless of the V600E mutation. Tumours without the mutation did not respond to treatment but those with the mutation did, and the dose was set at 960 mg twice daily⇑.

Thirty two more patients were then entered into the extension phase of the trial, all of whom had metastatic melanoma that was positive for the mutation. Melanoma disappeared in two of these participants and shrank in 24 of 32. Squamous cell carcinoma …