The Food and Drug Administration is looking at recent data suggesting that the cardiovascular event rate among patients on the weight-loss drug sibutramine was higher than among those on placebo.
“The analysis of these data is ongoing and FDA is making no conclusions about the preliminary findings at this time,” according to a statement posted on the agency's MedWatch site. These findings, the statement adds, “highlight the importance of avoiding the use of sibutramine” in patients with a history of coronary artery disease, congestive heart failure, arrhythmias, or stroke, which is recommended in the current sibutramine label.
Sibutramine is an orally administered drug marketed as Meridia by Abbott Laboratories. Its therapeutic effects result from norepinephrine, serotonin, and dopamine reuptake inhibition, according to the label. It was approved in 1997 for the management of obesity in conjunction with a reduced-calorie diet, and is recommended only for obese patients with an initial body mass index at or above 30 kg/m
The FDA reported results from a study of about 10,000 overweight or obese patients aged 55 years or older who had a history of heart disease or type 2 diabetes and one additional cardiovascular risk factor. The preliminary results of the study's primary end point—MI, stroke, resuscitated cardiac arrest, or death—were reported in 11.4% of those on sibutramine, compared with 10% of those on placebo. The difference was “higher than expected, suggesting that sibutramine is associated with an increased cardiovascular risk in the study population,” the FDA noted.
Abbott started the study, Sibutramine Cardiovascular Morbidity/Mortality Outcomes in Overweight or Obese Subjects at Risk of a Cardiovascular Event (SCOUT), in 2002 at the request of the FDA's European counterpart, the European Medicines Agency (EMEA), as one of the conditions for keeping the drug on the market in Europe after serious cardiovascular events were reported in the early 2000s. The study's aim was to evaluate the safety and efficacy of sibutramine in overweight and obese people.
The FDA was apprised of the results in mid-November. On Dec. 3, Public Citizen's Health Research Group, a health advocacy organization, filed a citizen's petition calling on the FDA to withdraw the drug from the market immediately, because of the new data indicating that it increases the risk of MI, stroke, resuscitated cardiac arrest, or death.
In 2005, the FDA denied a previous petition by the group requesting that sibutramine be taken off the market because of concerns over its safety arising from preapproval clinical studies.
In an interview, Dr. Sidney Wolfe, director of the Washington-based Health Research Group, said that the preliminary results of the SCOUT trial are a concern. The group continues to support the withdrawal of sibutramine from the market and is analyzing sibutramine-related reports in the FDA's adverse event reporting system database, he said.
Despite the label's recommendation that patients with risk factors such as cardiovascular disease not be treated with sibutramine, the drug is still prescribed to patients who are obese and have some of these risk factors, he noted.
Report adverse events to the FDA's MedWatch program at 800-332-1088 or www.accessdata.fda.gov/scripts/medwatch/medwatch-online.htmwww.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm191655.htm