Sanofi-Aventis has seen its new heart drug Multaq (dronedarone) knocked back by the US Food and Drug Administration, which yesterday gave it a non-approvable letter, sending the firm back to the drawing board and pushing dronedarone’s market debut in atrial fibrillation and atrial flutter back by at least two years.

The French company now has to wait for completion of the ATHENA study before re-filing the compound in the first part of 2008, and has been asked to boost its recruitment into the study from 3,700 to 4,300, which will not complete before the end of the year. ATHENA is designed to compare dronedarone and placebo in preventing cardiovascular hospitalizations or death from any cause in patients with atrial fibrillation or flutter and, secondarily, to determine the tolerability of the compound on a large scale.

Multaq was filed with the FDA in July last year and, the following November, researchers at the American Heart Association meeting were singing its praises as an effective but less toxic compound versus the gold-standard amiodarone. AF affects around 2 million people in the USA alone and can cause palpitations, shortness of breath and fatigue; it is estimated to account for between 15% and 20% of all strokes. Its prevalence is expected to reach 5.6 million in the US by 2050.

Lovenox trial postponed

Meanwhile, Sanofi-Aventis yesterday said that a trial against Teva Pharmaceutical and Amphastar concerning its patent armoury for the blood thinner Lovenox (enoxaparin) has been postponed. The trial was originally supposed to begin next month, but has been pushed back to December 4.