The Food and Drug Administration the powerful US Quango that controls the licensing of drugs, has ordered a pharmaceutical company to carry out more trials on a new weight loss drug it’s developing.

Last October, the FDA rejected the drug Lorcaserin basing its decision on a possibility that the compound is a cancer risk. The regulator also ordered research to be carried out to assess a potential link between Lorcaserin and the development of mammary tumours in rats. The FDA also wanted the company to see whether use of Lorcaserin increased release of protactin, a natural hormone released by the pituitary gland.

Despite carrying out these requests the FDA announced last week that they wanted the pharmaceutical company to carry out further trials; these trials must also include a 12 month study involving female rats.

Unfortunately for the pharmaceutical company, this new directive caused a share drop of some 15%.

On hearing the news one analyst said: “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.”

The company however disputes this analysis saying that they can resubmit Lorcaserin NDA by the end of this year.