The chances of Abbott Laboratories' Meridia remaining on the market in the USA have improved slightly after a regulatory advisory panel could not decide whether the controversial obesity drug should be pulled.

The US Food and Drug Administration's Endocrinologic and Metabolic Drugs Advisory Committee voted 8-8 as to whether Meridia (sibutramine) should be withdrawn. Their review had been prompted by data from the SCOUT study which investigated long-term cardiovascular effects of sibutramine in 10,000 patients, enrolled for up to six years, with high cardiovascular risk.

Those findings demonstrated an increased risk of stroke or heart attack, and the drug was pulled in Europe earlier this year, where it was sold as Reductil, Reduxade and Zelium.

Eight panellists said the potential for heart attacks and stroke outweighed any benefits of minor weight loss and wanted the drug to be pulled, while six recommended restricted sales and a black box warning. Two others said a warning and strict patient monitoring should be sufficient, while no panellists said no changes were necessary.

The vote "highlights the complexity of this scientific debate," said Eugene Sun, head of global pharmaceutical development at Abbott. He added that "we continue to believe that there are appropriate and identifiable patients that derive benefit from sibutramine" which is an important option "to treat a serious condition for which there are few treatment options".

He noted that Abbott has proposed "comprehensive risk management tools" to ensure doctors have the most relevant information for the continued appropriate use of the drug. Dr Sun added that sibutramine has been studied in more than 100 trials involving over 20,000 patients, in addition to those involved in SCOUT and the latter "did not directly assess the risk/benefit profile of the medication in patients for whom it is specifically intended".

As such, he argues, "its results cannot be readily extrapolated to the approved patient population, that is, patients who do not have a history of cardiovascular disease."

It is now up to the FDA to decide as to whether to keep Meridia on the market. It is not a big seller for Abbott which no longer promotes the drug in the USA and sales there this year are expected to be in the region of just $30 million.