FDA responds to outraged Arena investors

The FDA could announce its decision on Arena Pharmaceutical's obesity drug lorcaserin as early as today. The drug will have an uphill battle though, because an expert panel previously voted 9-to-5 against approval of the diet drug.

It's that vote that got a group of activist Arena investors steaming mad. The investors have launched a campaign blasting the advisory panel ruling, saying that the experts didn't give the drug a fair hearing. The group also contends that the drug is safer and more effective than the panel felt it was. "What has mobilized so many people, within our group and beyond, are the comments and behavior of some FDA officials and what we believe to be incorrect scientific conclusions," Arena shareholder Douglas Park tells the Wall Street Journal. Investors are particularly incensed by the panel's reaction to preclinical signs of tumors in rats injected with the therapy, noting that the agency's own rules allow panelists to disregard data from animal results based on doses 25 times stronger than what's given to humans.

The group's massive campaign has drawn a response from the FDA. Forbes' Matthew Herper published an FDA response letter received by one of the activist investors. "Although FDA strives to have broad representation of appropriate medical and scientific specialties on its advisory committees, optimal representation is often difficult to achieve given the strict conflict-of-interest regulations that apply, as well as calendar conflicts," the agency said in the letter. "In hindsight, FDA regrets that no toxicologist participated in the meeting. However, a team of FDA toxicology experts reviewed the lorcaserin NDA and interpreted the data related to the lorcaserin carcinogenicity studies."

The FDA does not have to follow the expert panel's recommendation, though it usually does. Even without the panel's vote it could be difficult for Arena to grab and approval on it's first go-around given the history of safety issues surrounding the obesity drug field.

- read the Forbes write-up, including the full FDA letter
- here's more from the Wall Street Journal