Experts seem divided over the safety of the diet pill Meridia manufactured by the Abbott Laboratories. The drug received a split recommendation on whether it should stay on in the market when it has been linked to heart attacks, strokes and deaths.
Outside advisers to the Food and Drug Administration, meeting in Adelphi, Maryland, on Wednesday voted 8-8 when asked whether the medicine should be withdrawn or remain available with new warnings or restrictions in its prescribing information. As in cases when there is a recommendation that isn't divided, the agency isn't bound by the panel's advice.
Meridia was approved in 1997 even as evidence showed it can raise blood pressure and heart rate. The drug was pulled in Europe in January after a study found 16 percent more major cardiovascular side effects among almost 10,000 high-risk patients who were followed as long as six years. Abbott estimates U.S. sales this year will be about $30 million.
Six panel members voted for a new boxed warning and restricted distribution of Meridia, and two panel members said a boxed warning would be sufficient. No one voted for a fourth option that called for no changes.
Opposing members of the panel cited the drug's limited use as support for leaving it on the market. Most insurers don't cover obesity treatments, so many patients pay out of pocket.
"The usage is falling off a cliff and patients aren't staying on the drug for very long," said John Flack, chairman of the department of internal medicine at Wayne State University School of Medicine in Detroit.
Abbott proposed limiting dispensing of the drug at a specialty pharmacy and urging closer monitoring of vital signs and weight during the first three months of treatment.
Abbott's Meridia (chemical name - sibutramine) is an appetite suppressant that has been available in the European Union since 1999 and in the USA since 1997. The weight loss drug is indicated for the weight management in conjunction with a reduced calorie diet in obese patients and in overweight patients who also have other obesity related diseases, such as type-2 diabetes or dyslipidaemia.
In January last the FDA had cited the Scout study to say "The preliminary data shows that cardiovascular events were reported in 11.4% of patients using sibutramine compared to 10% of patients using a placebo. This difference is higher than expected, suggesting that sibutramine is associated with an increased cardiovascular risk in the study population."
Although this difference may seem small, considering around 5000 patients would have been assigned to receive either placebo or sibutramine, this represents around 70 extra patients who experienced a cardiovascular event when treated with sibutramine compared to placebo. This increased heart risk clearly represents a health concern for regulators, who have recently reviewed the status of sibutramine as an approved obesity treatment.
The Sibutramine Cardiovascular OUTcomes (SCOUT) trial was a clinical study undertaken by the Abbott themselves.
But the company now argues that the Scout study is misleading because 90 percent of the participants would no longer get Meridia under the current prescribing information.
"Sibutramine is an important option for patients and physicians to treat a serious condition for which there are few treatment options currently available," said Eugene Sun, Abbott's vice president of global pharmaceutical development, in a statement released after the meeting. "Today's vote highlights the complexity of this scientific debate."
The FDA hasn't approved a new prescription drug for long-term weight loss since Swiss drugmaker Roche Holding AG's Xenical in 1999. New diet pills from Mountain View, California-based Vivus Inc., and Arena Pharmaceuticals Inc. and Orexigen Therapeutics Inc., both based in San Diego, are now under review at the FDA.
Safety concerns have prompted the FDA to withdraw 21 drugs from the market in the past 15 years, mostly over heart risks, according to agency data obtained by Bloomberg News.