Abbott will voluntarily withdraw Meridia (sibutramine) from the US market at the request of the US Food and Drug Administration (FDA).

The FDA's request is based primarily on the results of the SCOUT (Sibutramine Cardiovascular OUTcome Trial) study, an approximately 10,000 patient, 6-year study requested by European regulatory authorities as a post-marketing commitment to evaluate cardiovascular safety in high-risk patients. The majority of these patients had underlying cardiovascular disease and were not eligible to receive sibutramine under the current labelling.

The SCOUT results are in contrast to the vast body of sibutramine data for the on-label patient population, including 46 controlled clinical trials and more than 6 million patient years of use accumulated over 13 years during which the product has been available. These data fail to confirm the excess cardiovascular risk found in the SCOUT study.

The voluntary withdrawal of sibutramine in the US follows an 11-month process, beginning in November 2009, when Abbott promptly notified FDA of the SCOUT preliminary results immediately after receiving those results. The European Medicines Agency (EMA) suspended marketing authorization for all anti-obesity medicines containing sibutramine in January 2010.

Abbott submitted label changes to FDA in January 2010 to further ensure appropriate use of the product based on the preliminary SCOUT findings. Over the course of the next nine months, Abbott conducted and provided numerous analyses to FDA and other global regulatory authorities for the purpose of determining the applicability of the SCOUT data to the approved patient population. These analyses confirmed the appropriateness of the current label: that people with pre-existing cardiovascular disease should not take the medication. These analyses also confirmed there was no excess risk in the approved patient population.

Abbott provided a comprehensive review of these analyses at the September 15, 2010, public advisory panel with 16 experts selected by FDA. That panel reviewed and debated the available data on sibutramine. The results of the panel's deliberations – an 8-8 split decision with eight advisors voting in favour of enhanced labelling and risk management activities compared to eight advisors in favour of withdrawal – highlights the complexity of the scientific debate and the different interpretations of the data, even by independent experts.

Abbott believes sibutramine has a positive risk/benefit profile in the approved patient population, but will comply with the FDA's request.