The US Food and Drug Administration has expanded the approved uses of Bayer and Amgen unit Onyx Pharmaceuticals' Nexavar to treat the most common form of thyroid cancer.

Specifically, Nexavar (sorafenib) has got the green light for the treatment of metastatic differentiated thyroid carcinoma that is refractory to radioactive iodine treatment. The approval follows a priority review by the FDA for the oral multi-kinase inhibitor and is based on data from a trial which showed that Nexavar extended progression-free survival by 41% compared to placebo (10.8 months versus 5.8 months).

Richard Pazdur, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, noted that "differentiated thyroid cancer can be challenging to treat, especially when unresponsive to conventional therapies”. Nexavar is now the only FDA-approved treatment option for patients with this type of thyroid cancer.

The FDA approved Nexavar to treat advanced kidney cancer in 2005. In 2007, the agency expanded the drug’s label to treat liver cancer that cannot be surgically removed.