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Obesity drug

FDA approves second obesity drug

Vivus' Qsymia is a combination of two previously-approved drugs, phentermine and topiramate.
First FDA-approved once daily combination treatment for obesity
Vivus expects to launch the drug by the fourth quarter of 2012
Postmarketing studies to be conducted including one on long-term cardiovascular outcomes

The American FDA has approved Qsymia (phentermine and topiramate extended-release) as an addition to a reduced-calorie diet and exercise for chronic weight management.

The drug is the second weight loss drug to gain US clearance from the FDA, following the agency’s decision to approve Belviq (Arena Pharmaceuticals) in July 2012. Vivus expects to launch the drug by the fourth quarter of 2012.

“Qsymia is the first FDA-approved once daily combination treatment for patients struggling with obesity,” said Peter Tam, president of Vivus. “The degree and severity of obesity and the lack of effective pharmacological interventions that we face as a society were two primary reasons for the development of Qsymia.”

Qsymia drug is approved for use in adults with a BMI>30 or adults with a BMI>27 who have at least one weight-related condition such as hypertension, type 2 diabetes or dyslipidemia.

Qsymia is a combination of two FDA-approved drugs, phentermine and topiramate, in an extended-release formulation. Phentermine is indicated for short-term weight loss in overweight or obese adults who are exercising and eating a reduced calorie diet. Topiramate is indicated to treat certain types of seizures in people who have epilepsy and to prevent migraine headaches.

“Obesity threatens the overall well being of patients and is a major public health concern,” said Dr Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research. “Qsymia, used responsibly in combination with a healthy lifestyle that includes a reduced-calorie diet and exercise, provides another treatment option for chronic weight management in Americans who are obese or are overweight and have at least one weight-related comorbid condition.”

The safety and efficacy of Qsymia were evaluated in two randomised, placebo-controlled trials that included approximately 3,700 obese and overweight patients with and without significant weight-related conditions treated for one year. All patients received lifestyle modification that consisted of a reduced calorie diet and regular physical activity.

The recommended daily dose of Qsymia contains 7.5mg of phentermine and 46mg of topiramate extended-release. Qsymia is also available at a higher dose (15mg phentermine and 92mg of topiramate extended-release) for select patients.

Results from the two trials show that after one year of treatment with the recommended and highest daily dose of Qsymia, patients had an average weight loss of 6.7% and 8.9%, respectively, over treatment with placebo.

Approximately 62% and 69% of patients lost at least 5% of their body weight with the recommended dose and highest dose of Qsymia, respectively, compared with about 20% of patients treated with placebo.

Patients who did not lose at least 3% of their body weight by week 12 of treatment with Qsymia were unlikely to achieve and sustain weight loss with continued treatment at this dose. Therefore, response to therapy with the recommended daily dose of Qsymia should be evaluated by 12 weeks to determine, based on the amount of weight loss, whether to discontinue Qsymia or increase to the higher dose. 

If after 12 weeks on the higher dose of Qsymia, a patient does not lose at least 5% of body weight, then Qsymia should be discontinued, as these patients are unlikely to achieve clinically meaningful weight loss with continued treatment.

The FDA noted that Qsymia must not:

  • be used in patients with glaucoma or hyperthyroidism
  • be used in patients with recent (within the last six months) or unstable heart disease or stroke
  • be used during pregnancy because it can cause harm to a fetus (exposed to topiramate, in the first trimester of pregnancy has an increased risk of oral clefts)
  • females of reproductive potential must not be pregnant when starting Qsymia therapy or become pregnant while taking Qsymia.

The Agency also recommended:

  • females of reproductive potential should have a negative pregnancy test before starting Qsymia and every month while using the drug and should use effective contraception consistently while taking Qsymia.
  • regular monitoring of heart rate for all patients taking Qsymia, especially when starting Qsymia or increasing the dose.

The most common side effects of Qsymia are paresthesia, dizziness, altered taste sensation, insomnia, constipation and dry mouth.

The FDA approved Qsymia with a Risk Evaluation and Mitigation Strategy  (REMS) which consists of a Medication Guide advising patients about important safety information and elements to assure safe use that include prescriber training and pharmacy certification.

The purpose of the REMS is to educate prescribers and their patients about the increased risk of birth defects associated with first trimester exposure to Qsymia, the need for pregnancy prevention, and the need to discontinue therapy if pregnancy occurs. Qsymia will only be dispensed through specially certified pharmacies.

Vivus will be required to conduct ten 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.

Laurie Traetow, executive director of the American Society of Bariatric Physicians said, “Obesity medicine specialists are excited about the FDA adding another tool to the obesity treatment toolbox, which for so many years had been virtually barren in the pharmacotherapy area.”

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