WASHINGTON, D.C. ( TheStreet) -- Vivus ( VVUS): Take two. A panel of outside experts impaneled by the U.S. Food and Drug Administration gathers today to review and pass judgment on Vivus' experimental obesity pill Qnexa. Once again, Qnexa's safety will be the most hotly debated topic. At Vivus' first advisory panel last year, experts voted 10-6 to not recommend Qnexa's approval. While Qnexa helped patients lose about 10% of their body weight, the drug fell short due to safety concerns focused mostly on potential cardiovascular problems and a higher risk of cleft lips in children born to women who might get pregnant while prescribed Qnexa. FDA followed the advice of its advisory panel and rejected Qnexa in October 2010. Vivus resubmitted Qnexa with longer-term data and analyses designed to ameliorate the agency's safety concerns. In a second review of Qnexa posted Friday, FDA officials once again raised concerns about the drug's potential risk for birth defects and heart problems. But the agency also recognized Qnexa's ability to help patients lose weight and largely deferred overall judgment on the drug, choosing instead to allow the outside experts on the panel to weigh in with their recommendations. Obesity has become an epidemic in the U.S., leading many public health officials to call for the FDA to approve a medicinal therapy to help people lose weight when exercise and diet are not enough. FDA, however, has taken a conservative stance when it comes to reviewing and regulating diet drugs. Some approved pills, like Abbott's ( ABT) Meridia, have been pulled from the market at the FDA's request due to safety concerns. Last year, FDA also rejected three experimental obesity pills from Arena Pharmaceuticals ( ARNA), Orexigen Therapeutics ( OREX) and Vivus. Vivus' Qnexa is comprised of two currently approved drugs -- phentermine, a generic weight loss drug, and topiramate, used to treat epilepsy and migraines. Vivus shares closed Tuesday at $10.55. The stock will be halted Wednesday for the Qnexa advisory panel. --Written by Adam Feuerstein in Boston. >To contact the writer of this article, click here: Adam Feuerstein. >To follow the writer on Twitter, go to http://twitter.com/adamfeuerstein.