Arena Shares Fall After FDA Rejection of Lorcaserin Diet Drug

Arena Pharmaceuticals Inc. fell in early trading after the company failed to win U.S. approval for diet pill lorcaserin as an advisory panel said the weight loss achieved with the medicine didn’t justify the risk of cancer.

Arena slid 18 cents, or 11 percent, to $1.45 at 7:37 a.m. before the open of the Nasdaq Stock Market. The shares had dropped 59 percent this year after regulators suggested that lorcaserin wouldn’t be approved.

The Food and Drug Administration asked for more information on the drug for the one-third of Americans who are obese, Arena said in a statement released on Oct. 23. Lorcaserin is the San Diego-based company’s first product and is licensed by Tokyo- based Eisai Co.

Arena is competing with Mountain View, California-based Vivus Inc. and San Diego-based Orexigen Therapeutics Inc. to introduce the first prescription weight-loss drug in more than a decade. Safety issues spelled the demise of Wyeth’s fen-phen in 1997, Sanofi-Aventis SA’s rimonabant in 2007 and Abbott Laboratories’ Meridia this month.

“If FDA holds to a higher standard on weight-loss pills, we will get better ones,” said Diana Zuckerman, president of the National Research Center for Women & Families, before the announcement.

Lorcaserin was linked to cancers in studies of rats and helped people lose 3 percent more weight than a placebo, short of the recommended 5 percent, according to an FDA staff review released Sept. 14. A panel of doctors and scientists advising the agency voted 9-5 against recommending approval on Sept. 16.

Diabetes Risk

The FDA in its response letter said further studies may be needed to understand the drug’s risks versus benefits.

Arena will meet and work with the FDA “as quickly as possible” to better understand what the agency wants, Jack Lief, Arena’s chief executive officer, said in the statement.

Before the vote, Jon Lecroy, an analyst at Hapoalim Securities in New York, had said peak sales of lorcaserin may reach $800 million globally in 2015.

Two-thirds of American adults are overweight, raising their risk of diabetes, heart disease, high blood pressure and cancer, according to the 2008 National Health and Nutrition Examination Survey. More than one-third of American adults are obese, measured as a ratio between height and weight.

Vivus is scheduled to hear by Oct. 28 the response to its application to sell a diet pill called Qnexa. An advisory panel voted 10-6 against approval because of concerns the drug may cause birth defects and increased heart rate. The pill works better than lorcaserin and Eric Colman, deputy director of the FDA’s Division of Metabolism and Endocrinology Products, said he was surprised by the advisory panel’s vote.

Orexigen and partner Takeda Pharmaceutical Co., of Osaka, Japan, plan to present their diet pill, Contrave, to an advisory panel Dec. 7. The FDA is scheduled to make a decision on the drug by Jan. 31.

To contact the reporter on this story: Catherine Larkin in Washington at clarkin4@bloomberg.net.

To contact the editor responsible for this story: Reg Gale at rgale5@bloomberg.net.

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