Exelixis has received orphan drug designation from the US Food and Drug Administration (FDA) for XL184 to treat follicular, medullary, and anaplastic thyroid carcinoma, and metastatic or locally advanced papillary thyroid cancer.

A Phase III trial of XL184 in patients medullary thyroid cancer is being conducted.

Exelixis expects to release top-line Phase III results in the first-half of 2011 and file a new drug application for the compound in the second half of the year.

The company is evaluating XL184 in a Phase II trial in patients with solid tumours including metastatic castration-resistant prostate cancer, ovarian cancer, melanoma, breast cancer, non-small cell lung cancer and hepatocellular cancer.

It is also evaluating XL184 in a Phase 1 trial in renal cell carcinoma and differentiated thyroid cancer patients, and in a Phase II trial in in recurrent glioblastoma patients.

The FDA grants orphan drug designation to drugs that treat diseases that affect fewer than 200,000 people in the US.