Arena’s Lorcaserin Rejected by FDA on Concern Over Cancer Risk

(Bloomberg) -- Arena Pharmaceuticals Inc. failed to win U.S. approval for its diet pill lorcaserin after an advisory panel said the weight loss achieved with the medicine didn’t justify the risk of cancer.

The Food and Drug Administration asked for more information on the drug for the one-third of Americans who are obese, Arena said today in a statement yesterday. 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.

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.

Diabetes Risk

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.

Arena shares rose 17 cents, or 12 percent, to $1.63 in Nasdaq Stock Market trading yesterday. The shares had dropped 59 percent this year after regulators suggested that lorcaserin wouldn’t be approved. Eisai fell 22 yen to 2786 in trading in Tokyo.