Landmark ATHENA Study With Dronedarone (Multaq(R)) Shows 24% Reduction In Cardiovascular Hospitalisation Or Death In Patients With Atrial Fibrillation

Sanofi-aventis (EURONEXT: SAN and NYSE: SNY) announced that findings from the landmark ATHENA study showed dronedarone (Multaq®), a potential therapy for the treatment of patients with atrial fibrillation or atrial flutter, decreased the risk of cardiovascular hospitalisations or death from any cause by a statistically significant 24% (p=0.00000002), meeting the study primary endpoint.

The ATHENA results will be presented at the late breaking clinical trial session of Heart Rhythm 2008, the Heart Rhythm Society's 29th Annual Scientific Sessions in San Francisco, USA.

For the first time in twenty years of clinical drug trials in atrial fibrillation, an investigational medicine, dronedarone, showed a significant decrease in the risk of cardiovascular death by 30% (p=0.03) on top of standard therapy, including rate control and antithrombotic drugs, in patients with atrial fibrillation or atrial flutter. Dronedarone also significantly decreased the risk for arrhythmic death by 45% (p=0.01) and there were numerically less deaths (16%) from any cause in the dronedarone group compared to placebo (p=0.17). First cardiovascular hospitalisation was reduced by 25% (p=0.000000009) in the dronedarone group.

"The ATHENA results have the potential to change the face of atrial fibrillation management. For atrial fibrillation patients, who together with their physicians struggle on a daily basis to manage the dramatic consequences of this complex disease, Multaq®carries hope for patients" said Marc Cluzel, sanofi-aventisSenior Vice President, R&D. "This milestone is indicative of sanofi-aventis' commitment to bringing innovative therapies to market, and of our ongoing commitment to provide patients, physicians and public health stakeholders with breakthrough medicines in those therapeutic areas where there are major healthcare needs and limited solutions".

Atrial fibrillation is a major cause of hospitalisation and mortality and affects about 2.5 million people in the United States, as well as 4.5 million people in the European Union and is emerging as a growing public health concern because of the aging of the population. Patients suffering from atrial fibrillation have twice the risk of death, an increased risk of stroke and cardiovascular complications, including congestive heart failure. Furthermore atrial fibrillation considerably impairs patients' lives, mainly because of their inability to perform normal daily activities due to complaints of palpitations, chest pain, dyspnoea, fatigue or light-headedness, without consideration of the cumbersome and sometime serious constraints imposed by current therapies of atrial fibrillation.

"In atrial fibrillation where treatment morbidity-mortality benefit still needed to be demonstrated, ATHENA is a unique trial using clinically relevant outcomes such as cardiovascular hospitalisation or death as the primary endpoint. In this regard, the trial has clearly achieved these safety and efficacy endpoints," said Dr Stefan H. Hohnloser, J.W. from the Goethe University, Division of Clinical Electrophysiology, Frankfurt, Germany, who served as co-principal investigator of the ATHENA study. "As a consequence, dronedarone is the first treatment for atrial fibrillation which has been demonstrated to reduce cardiovascular hospitalisation or mortality in patients with AF."

The most frequently reported adverse events of dronedarone vs placebo induced gastro-intestinal effect (26% vs 22%), skin disorder (10% vs 8%, mainly rash) and increased blood creatinine (4.7% vs 1%). The mechanism of blood creatinine increase (inhibition of creatinine secretion at the renal tubular level) is well defined. Compared to placebo, dronedarone showed low risk of pro-arrhythmia and no excess of hospitalisations for congestive heart failure. There was a similar rate of study drug discontinuation between the two study groups.

"ATHENA is truly a landmark trial, that marks a paradigm change for the management of atrial fibrillation," said Dr Christopher Cannon, a Senior Investigator in the TIMI Study Group at Brigham and Women's Hospital, who was not involved in the study. "Atrial fibrillation is a very common disease, and our prior treatment options have been focused only on symptom relief and a hope to not do harm, which has been the problem with prior antiarrhythmic drugs. Now, with a highly significant reduction in death or hospitalisation, as well as a 45% reduction in arrhythmic death or 30% cardiovascular death, dronedarone may become a first line treatment of atrial fibrillation".

ATHENA, the largest double blind randomised study in patients with atrial fibrillation, was conducted in more than 550 sites in 37 countries and enrolled a total of 4,628 patients. The ATHENA landmark trial is the first morbidity-mortality study as part of the dronedaronephase III clinical development program, which also included five other multinational clinical studies, an initial study in severe cardiac heart failure and a recent decompensationpatients ANDROMEDA, and a total of 4 international studies in atrial fibrillation: EURIDIS/ADONIS, ERATO, and the ongoing DIONYSOS trial.

Based upon this new clinical data, sanofi-aventis plans to submit a registration dossier to the European Medicines Agency (EMEA), and a new drug application (NDA) to the U.S. Food and Drug Administration (FDA) during the 3rd quarter of 2008.