Qnexa Approval in the Works
Written by Faith Anderson on February 25, 2012
Qnexa Combines Two Potentially Dangerous Drugs into One
The diet pill Qnexa uses a combination of two drugs: phentermine, an appetite suppressant, and topiramate, an anticonvulsant sold by Johnson & Johnson as Topamax, a treatment for epilepsy and migraine headaches. Topiramate is believed to make patients feel more satiated, although it is unclear how the drug achieves this benefit. Johnson & Johnson initially studied Topamax alone as a weight loss treatment, but ultimately concluded that the associated side effects were too significant. Recent studies and FDA warnings have warned consumers that taking topiramate (Topamax) during pregnancy can cause major birth defects in babies, including cleft lip and cleft palate.
“Having a drug for obesity would be like telling me you had a drug for the fever,” said Dr. Mitchell Roslin, chief of bariatric surgery at Northern Westchester Hospital in New York. “There can be millions of different reasons why someone is obese; it’s really a symptoms of various underlying mechanisms.” Regardless, many believe that a safe and effective diet pill would be an easy sell in the United States, where the obesity rate is nearing 35%. Unfortunately, there doesn’t seem to be any way to create an effective diet pill without also creating major side effect risks.
Weight Loss Pills and Life-Threatening Side Effects
Early attempts at treating obesity focused on speeding up metabolism, which is the body’s method for breaking down food into energy. The speed of metabolism controls how quickly or slowly we burn calories and ultimately determines how much weight we put on. In the 1930s, doctors prescribed an industrial chemical called dinitrophenol for weight loss, which effectively accelerated metabolism, but also caused swelling, fever and deadly toxicity in some patients. The result? The establishment of the Food and Drug Administration, charged with evaluating and approving medications for consumer use.
Perhaps the worst diet pill debacle to date involved fen-phen, the weight loss drug that combined phentermine and another drug marketed in the 1990s by Wyeth Pharmaceuticals called fenfluramine. The combination drug was never approved by the FDA, but, because the agency doesn’t regulate doctors’ decisions to prescribe combinations of drugs, more than 18 million fen-phen prescriptions were written by 1996. One year later, research suggested that up to one-third of patients taking fen-phen suffered from heart valve damage, and in 1997, Wyeth was forced to recall two versions of fenfluramine and pay more than $13 billion to settle fen-phen personal injury lawsuits.
Qnexa Approval Could Mean Weight Loss But With Birth Defect Risk
In light of disastrous diet pill attempts in the past, drug makers are now focusing on medications that block brain signals associated with appetite and food cravings. Vivus’ Qnexa is one of three drugs currently seeking FDA approval for weight loss, and, despite the diet drug’s earlier rejection for serious side effects, a panel of FDA doctors voted 20-2 in favor of approving the weight loss medication during its second review. The panel cited the drug’s benefits, which include weight loss of nearly 10% for most patients taking the drug for over a year, the highest reduction reported with any recent diet pill. However, panelists stressed that Vivus must be required to conduct a large, follow-up study of potential adverse effects on the heart. “The potential benefits of this medication seem to trump the side effects,” reported FDA panel member Dr. Kenneth Burman of the Washington Hospital Center in Washington DC. “But in truth, only time will tell.” The FDA is expected to issue its decision regarding Qnexa by mid-April.