(Reuters) - Shares of Arena Pharmaceuticals Inc (ARNA.O) fell 15 percent in pre-market trade on Friday, a day after the company said U.S. health regulators demanded additional safety studies to approve its experimental weight-loss drug, potentially delaying its market debut.
In October, the health regulator rejected Arena’s lorcaserin, citing cancer risks. It also sought a three-month study to establish a causal relationship between the drug, mammary tumor development in rats and elevation in prolactin — a hormone released by the pituitary gland.
On Thursday, the company said the U.S. Food and Drug Administration requested several additional studies, including a separate 12-month trial in female rats to correlate a temporary elevation in prolactin levels to mammary tumors.
“We believe the new requests add to the regulatory uncertainty and will most likely push out resubmission of the NDA (new drug application) beyond the company’s guidance of end of 2011,” Leerink Swann analyst Steve Yoo wrote in a note to clients.
Arena, however, said it can resubmit the lorcaserin NDA by the end of 2011.
Shares of the company were down 15 percent at $1.71 in trading before the bell. They closed at $2.00 on Thursday on Nasdaq.
Reporting by Anand Basu in Bangalore; Editing by Anne Pallivathuckal