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Jan. 21, 2011, 4:34 p.m. EST

FDA Seeks Data on Vivus Obesity Drug

By Thomas Gryta

NEW YORK—Vivus Inc. was dealt a setback in getting weight-loss drug Qnexa to the market after the Food and Drug Administration asked whether prior data may shed light on the risk of birth defects from the drug.

The FDA has asked Vivus to assess the feasibility of analyzing prior databases to determine whether topiramate, an ingredient in the drug, causes birth defects. Vivus said it will determine the timeline for resubmitting its application for Qnexa to the FDA after it finishes the feasibility assessment.

Based on talks with the FDA, Vivus believes the new request stems from published reports derived from pregnancy registries that show defects from topiramate use in two children born in the U.K. and four in North America. Vivus said there were no reports of any fetal malformations in the 15 births from women exposed to Qnexa or topiramate in the initial Qnexa clinical studies.

Vivus is one of three companies trying to get a new obesity treatment approved in the U.S. Vivus and Arena Pharmaceuticals (NAS:ARNA) Inc. both had their diet drugs rejected by FDA panels and ultimately by the agency itself. Orexigen Therapeutics Inc.'s weight-loss drug Contrave got a positive recommendation from a panel in December and is expecting an FDA decision later this month.

Shares of Vivus dropped 16% to $8.74 Friday afternoon in 4 p.m. trading on the Nasdaq Stock Market, while Orexigen fell 4.4% to $8.64 and Arena shares lost 3.4% to $1.90.

Qnexa is a combination of stimulant phentermine and antiseizure drug topiramate, sold as Topamax by Johnson & Johnson (NYS:JNJ) . The two drugs work together to reduce appetite and make the user feel more satisfied.

The requested investigation of health-care records would determine the incidence of oral clefts in children born to women using topiramate for preventing migraines. The dosage used in Qnexa is closer to that used for migraines than the higher amounts used in treating epilepsy.

The FDA initially rejected Qnexa in October, asking for an assessment of Qnexa's potential to cause birth defects and evidence that the product doesn't increase the risk for major adverse cardiovascular events.

Vivus didn't mention the cardiovascular concerns in its statement Friday, and a spokesman said the company isn't commenting beyond what is included in the press release.

Vivus also has a marketing application pending with the European Medicines Agency for Qnexa.

Orexigen is developing Contrave with Japan's Takeda Pharmaceutical (TKS:JP:4502) Co., while Arena is working with that country's Eisai (TKS:JP:4523) Co. on lorcaserin.

Drew FitzGerald contributed to this article.

Write to Thomas Gryta at thomas.gryta@dowjones.com

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