Sibutramine May Increase Cardiovascular-Event Risk

Kate Traynor

BETHESDA, MD 23 November 2009—Preliminary data from a placebo-controlled, 10,000-patient study suggest that the antiobesity drug sibutramine may increase patients' risk of cardiovascular adverse events, FDA announced on Friday.

The agency cautioned that it has not verified the risk but is conducting an expedited safety review of the data because of the potential seriousness of the problem.

According to FDA, the preliminary data are from the Sibutramine Cardiovascular Morbidity/Mortality Outcomes in Overweight or Obese Subjects at Risk of a Cardiovascular Event (SCOUT) trial, a postmarketing study that began in 2002.

The data compared rates of heart attack, stroke, resuscitated cardiac arrest, or death in patients taking sibutramine or a placebo for weight loss, the agency stated.

According to FDA, 11.4% of study participants receiving sibutramine plus standard care and 10% of those receiving a placebo plus standard care had a cardiovascular event. FDA stated that the difference in cardiovascular adverse event rates between the group was "higher than expected, suggesting that sibutramine is associated with an increased cardiovascular risk in the study population."

Study enrollees were at least 55 years of age, overweight or obese, and had a history of heart disease or type 2 diabetes and one additional cardiovascular risk factor.

FDA stated that the preliminary data reinforce the need to follow recommendations in sibutramine's labeling and avoid using the drug in patients with coronary artery disease, congestive heart failure, arrhythmias, or stroke.

The agency stated that it is continuing its review of the SCOUT data and will release its conclusions when the review is complete.