* Says to file for market approval in second half of yr
* Shares up 6 pct premarket
Jan 10 (Reuters) - Exelixis Inc (EXEL.O) said its lead experimental cancer drug was granted orphan drug status, sending its shares up 6 percent in premarket trade.
The company also said it expects to file for marketing application of the drug, XL184, as treatment for a type of thyroid cancer in the second half of this year.
Orphan drug designation is granted by the U.S. Food and Drug Administration to drugs that treat a condition affecting less than 200,000 Americans, and gives the drugmaker marketing exclusivity of seven years in the country, upon approval.
Exelixis’ shares, which have risen 28 percent since the company reported positive data from studies of the drug for prostrate and ovarian cancer in November, were at $8.49 in premarket trade on Monday. They closed at $8.00 on Friday on Nasdaq. (Reporting by Shravya Jain in Bangalore; Editing by Unnikrishnan Nair)