With the Centers for Disease Control and Prevention estimating that one-third of the U.S. population is obese, obesity drugs vying for a spot in the marketplace have been in the spotlight lately.
On July 17, the FDA approved Qsymia (phentermine and topiramate), formerly known as Qnexa. The drug was approved as an adjunct to diet and exercise in obese patients with a body mass index (BMI) of 30 or more or overweight patients with a BMI of 27 who have at least one weight-related comorbidity, such as type 2 diabetes or hypertension. According to the FDA, patients enrolled in a study that delivered the recommended daily dose of Qsymia had an average weight loss of 6.7 percent and 62 percent of the patients lost at least five percent of their body weight. In another study, patients who received the highest daily dose saw an average weight loss of 8.9 percent and 69 percent lost at least five percent of their body weight.
However, the drug’s manufacturer is required by the Agency to "conduct 10 postmarketing requirements, including a long-term cardiovascular outcomes trial to assess the effect of Qsymia on the risk for major adverse cardiac events such as heart attack and stroke."
The FDA noted, "Qsymia can increase heart rate; this drug’s effect on heart rate in patients at high risk for heart attack or stroke is not known. Therefore, the use of Qsymia in patients with recent (within the last six months) or unstable heart disease or stroke is not recommended. Regular monitoring of heart rate is recommended for all patients taking Qsymia, especially when starting Qsymia or increasing the dose."
Following the announcement, ACC President William Zoghbi, MD, FACC, commented, "We welcome a new tool, in addition to healthy diet and exercise, to help patients combat obesity. However, it is important to continuously evaluate the overall risks and benefits of any weight-loss aid. Weight-loss drugs have the potential to help manage a major health problem, but it is most important to understand the impact the medications may have on long-term cardiovascular health and patient outcome."
In February, an FDA advisory panel recommended approving Qnexa. In March 2012, the Endocrinologic and Metabolic Drugs Advisory Committee, an advisory panel for the FDA, voted 17-6 to require obesity drugs to undergo more stringent clinical trials to assess cardiovascular risks. The panel made its recommendation after a two-day meeting discussing the development of obesity drugs and recommendations for phase two and three clinical trials. The discussions focused on results of the Look AHEAD (Action for Health in Diabetes), SCOUT and CRESCENDO trials. Following the panel’s extension recommendation, the FDA announced in April that they would take an additional three months to review Qnexa.
"We have to assess overall outcome and therefore risk and benefit of any drug intervention in the long run," said ACC President William Zoghbi, MD, FACC, following news of the extension."Since obesity drugs work by a wide variety of mechanisms, evaluating their effect on traditional cardiovascular risk in addition to possible effects on cardiac valves and pulmonary pressures is essential."
On June 27, the FDA gave a nod to another obesity drug, lorcaserin hydrochloride (Belviq), making it the first prescription weight-loss pill to be approved in more than a decade. In May, the Agency’s Endocrinologic and Metabolic Drugs Advisory Committee voted in favor of approval. Similar to Qsymia, the serotonin 2c receptor agonist, was cleared as an aid to diet and exercise in obese and overweight patients. However, according to the prescribing information, "the effect of Belviq on cardiovascular morbidity and mortality has not been established."
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