Multaq(R) First-line Option in New 2010 ESC Guidelines for the Management of Atrial Fibrillation

PARIS, August 29, 2010 - Sanofi aventis (EURONEXT: SAN and NYSE: SNY) announced today
that the European Society of Cardiology (ESC) 2010 new Guidelines for the
Management of Atrial Fibrillation (AF) have been released and recommend that
Multaq(R) (dronedarone) should be used for maintenance of sinus rhythm as a
first-line treatment option in all patients with paroxysmal and persistent AF
(class of recommendation I, level of evidence A) other than those with CHF
NYHA class III/IV or unstable CHF NYHA class II (class of recommendation III,
level of evidence B).

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Multaq(R) was granted a Class I recommendation, a designation
assigned in the guidelines when "there is evidence and/or general agreement
that a given procedure/therapy is beneficial, useful, and effective." The
Task Force for the Management of Atrial Fibrillation of the ESC recognised
the extensive clinical development of Multaq(R), giving it their highest
ranking A for level of evidence. Moreover, the guidelines recommend that
Multaq(R) may also be used to achieve rate control in non-permanent AF except
for patients with NYHA class III - IV or unstable heart failure (class of
recommendation IIa, level of evidence B).(1)

Importantly the new guidelines include, for the first time, a
statement on the importance of reducing hospitalisation as a key therapeutic
goal in the management of AF. They also state that Multaq(R) should be
considered in order to reduce cardiovascular hospitalisation in patients with
non-permanent AF and cardiovascular risk factors (Class of recommendation
IIa, level of evidence B) as well as in patients with AF and stable heart
failure (NYHA Class I, II) (Class of recommendation IIa, level of evidence
C).(1)

The guidelines do not recommend use of Multaq(R) in patients
with NYHA class III and IV or with recently unstable (decompensation within
the prior month) NYHA class II heart failure.(1)

"Sanofi-aventis is pleased with this first-line recommendation
for Multaq(R) in the AF guidelines which recognises the extensive clinical
development for the product as well as the innovative outcome of reducing
cardiovascular hospitalisation as demonstrated in the ATHENA trial," said
Marc Cluzel, M.D., PhD, Executive Vice President, Research and Development,
sanofi-aventis. "Multaq(R) provides symptom control and for the first time
for an anti-arrhythmic drug, a long term benefit by reducing the risk of
distressing and repeat cardiovascular hospitalisations. AF Hospitalisations
represent a significant human and economic burden for patients, healthcare
practitioners and payers as recently reported."(2)

More about the Guidelines

ESC Clinical Practice Guidelines are scientifically recognised
worldwide as providing practicing physicians with the best possible
recommendations on diagnosis, treatment and management of specific topics in
cardiology medicine. Guidelines are created and edited under the umbrella of
the ESC Board and the Committee for Practice Guidelines (CPG), who form a
Task Force of appropriate experts from the ESC Associations, Working Groups,
Councils, and National Societies, and from other bodies when required. They
are the result of consensus amongst the Task Force appointed to prepare them,
and they are peer-reviewed in a thorough and rigorous process that ensures
accuracy, best-practice and relevance. Guidelines are available in a variety
of printed and electronic media and in multiple formats including full
documents, pocket guides and summaries.(1)

About Atrial Fibrillation

The incidence of atrial fibrillation is growing worldwide in
relation to aging populations. It is emerging as a public health concern,
affects about 4.5 million people in Europe and represents one-third of
hospitalizations for arrhythmia in the European Union.(3) Atrial fibrillation
leads to potential life-threatening complications. AF increases the risk of
stroke up to five-fold (4), worsens the prognosis of patients with
cardiovascular risk factors (5), and doubles the risk of mortality (6) with
significant burden on patients, health care providers and payers. Seventy
percent of AF management costs are driven by hospital care and interventional
procedures in the European Union.(7)

About AF Hospitalisation

AF is associated with high rates of hospitalisation.(3) There
are a variety of reasons for AF hospitalisation, including palpitations,
initiation of antiarrhythmic therapy, procedures, complications of co-morbid
conditions, as well as readmissions related to these causes. There is
evidence that the rate of AF-related hospitalisations and associated cost is
increasing over time, mainly because of the aging population.(3) In the U.S.,
hospitalisations for AF were almost three times higher in 2000 compared to
two decades earlier.(8) In France, one study found that 31.3 percent of AF
patients were hospitalised over a one-year period.(9)

AF is a chronic, progressive disease and cost increases with
each recurrence, mainly driven by hospitalisation. The proportion of
expenditure for AF treatment attributable to hospitalisation ranges from 44 -
73 percent. (7,10,11,12,13) The total cost burden across five EU countries
was approximated at more than 6 billion Euros.(9,12) In the UK, National
Health Service spending for AF hospital admissions increased 2.2-fold between
1995 and 2000.(11)

About Multaq(R)

Multaq(R), discovered and developed by sanofi-aventis, has
been studied in a clinical development program, including seven
international, multicenter, randomized clinical trials involving more than
7000 patients with almost 4000 patients receiving Multaq(R). The landmark
ATHENA trial was the largest anti-arrhythmic drug trial conducted in patients
with AF/AFL, involving 4,628 patients with a follow-up of 30 months. In this
trial, Multaq(R), on top of standard cardiovascular therapy, significantly
reduced cardiovascular hospitalization or death by 24 percent (p<0.001) when
compared to placebo, meeting the study's primary endpoint. This result was
entirely attributable to a reduction in cardiovascular hospitalization.

Multaq(R) has a fixed dose regimen of twice daily 400 mg
tablets to be taken with morning and evening meals. Treatment with Multaq(R)
does not require a loading dose and can be initiated in an outpatient
setting. Most common adverse reactions are diarrhea, nausea, vomiting,
abdominal pain, asthenia (weakness) and skin rash.

The European Commission granted marketing authorization for
Multaq(R) in November 2009. Multaq(R) is indicated in the EU in adult
clinically stable patients with a history of, or current non-permanent atrial
fibrillation (AF) to prevent recurrence of AF or to lower ventricular rate.
The use of Multaq(R) in unstable patients with NYHA class III and IV heart
failure is contraindicated. Because of limited experience in stable patients
with recent (1 to 3 months) NYHA class III heart failure or with Left
Ventricular Ejection Fraction (LVEF) <35%, the use of Multaq(R) is not
recommended in these patients.(14)

In the U.S., Multaq(R) is indicated to reduce the risk of
cardiovascular hospitalization in patients with paroxysmal or persistent
atrial fibrillation (AF) or atrial flutter (AFL), with a recent episode of
AF/AFL and associated cardiovascular risk factors (i.e., age >70,
hypertension, diabetes, prior cerebrovascular accident, left atrial diameter
is greater than or equal to 50 mm or left ventricular ejection fraction
[LVEF] <40%), who are in sinus rhythm or who will be cardioverted.(15)
Multaq(R) is contraindicated in patients with NYHA Class IV heart failure,
or NYHA Class II-III heart failure with a recent decompensation requiring
hospitalization or referral to a specialized heart failure clinic.

Multaq(R) is currently available in 20 countries including the
U.S., Canada, Switzerland, Mexico, Taiwan, South Korea, Germany, Denmark,
Ireland, Norway, Finland, Austria, Cyprus, Malta, Estonia, Sweden, Israel,
Peru, Mexico, Hong Kong the UK and is being launched in most European
countries in 2010.

For more information about AF and Multaq(R):
www.dronedarone-atrial-fibrillation-pressoffice.com

About sanofi-aventis

Sanofi-aventis, a leading global pharmaceutical company,
discovers, develops and distributes therapeutic solutions to improve the
lives of everyone. Sanofi-aventis is listed in Paris (EURONEXT: SAN) and in
New York (NYSE: SNY). For more information, please visit:
www.sanofi-aventis.com.

Forward-Looking Statements

This press release contains forward-looking statements as
defined in the Private Securities Litigation Reform Act of 1995, as amended.
Forward-looking statements are statements that are not historical facts.
These statements include projections and estimates and their underlying
assumptions, statements regarding plans, objectives, intentions and
expectations with respect to future financial results, events, operations,
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performance. Forward-looking statements are generally identified by the words
"expects," "anticipates," "believes," "intends," "estimates," "plans" and
similar expressions. Although sanofi-aventis' management believes that the
expectations reflected in such forward-looking statements are reasonable,
investors are cautioned that forward-looking information and statements are
subject to various risks and uncertainties, many of which are difficult to
predict and generally beyond the control of sanofi-aventis, that could cause
actual results and developments to differ materially from those expressed in,
or implied or projected by, the forward-looking information and statements.
These risks and uncertainties include among other things, the uncertainties
inherent in research and development, future clinical data and analysis,
including post marketing, decisions by regulatory authorities, such as the
FDA or the EMA, regarding whether and when to approve any drug, device or
biological application that may be filed for any such product candidates as
well as their decisions regarding labelling and other matters that could
affect the availability or commercial potential of such products candidates,
the absence of guarantee that the products candidates if approved will be
commercially successful, the future approval and commercial success of
therapeutic alternatives, the Group's ability to benefit from external growth
opportunities as well as those discussed or identified in the public filings
with the SEC and the AMF made by sanofi-aventis, including those listed under
"Risk Factors" and "Cautionary Statement Regarding Forward-Looking
Statements" in sanofi-aventis' annual report on Form 20-F for the year ended
December 31, 2009. Other than as required by applicable law, sanofi-aventis
does not undertake any obligation to update or revise any forward-looking
information or statements.

____________________________

1. The Task Force for the Management of Atrial Fibrillation of the
European Society of Cardiology. European Heart Journal 2010. doi:
10.1093/eurheartj/ehq278. Guidelines for the management of atrial
fibrillation. eurheartj.oxfordjournals.org/

2. National Services Framework for Coronary Heart Disease. Chapter Eight:
Arrhythmia and Sudden Cardiac Death. March 2005

3. Go AS, Hylek EM, Phillips KA, et al. Prevalence of diagnosed atrial
fibrillation in adults: national implications for rhythm management and
stroke prevention: the Anticoagulation and Risk Factors in Atrial
Fibrillation (ATRIA) Study. JAMA 2001; 285:2370-5.

4. Lloyd-Jones et al. Lifetime Risk for Development of Atrial
Fibrillation: The Framingham Heart Study. Circulation. 2004; 110:1042-1046.

5. Fuster V et al. ACC/AHA/ESC 2006 guidelines for the management of
patients with atrial fibrillation. European Heart Journal (2006) 27,
1979-2030.

6. Benjamin EJ, Wolf PA, D'Agostino RB, Silbershatz H, Kannel WB, Levy D.
Impact of atrial fibrillation on the risk of death: the Framingham Heart
Study. Circulation 1998 Sep 8; 98(10):946-52.

7. Ringborg et all, Europace 2008 10; 400-411

8. Wattigney WA et al. Circulation 2003;108:711-6

9. Le Heuzey JY et al. Am Heart J 2004;147:121-6

10. Coyne KS et al. Value Health 2006;9:348-56

11. Stewart S et al. Heart 2004;90:286-92

12. Reynolds MR et al. J Cardiovasc Electrophysiol 2007;18:628-33

13. McBride D et al. Value Health 2008;12:293-301

14. European Medicines Agency. European Public Assessment Report. Doc.
Ref.: EMA/625172/2009; EMEA/H/C/1043
www.ema.europa.eu/ema/index.jsp?curl=pages/medicines/human/medicines/001043/human_med_001207.jsp&murl=menus/medicines/medicines.jsp&mid=WC0b01ac058001d124&jsenabled=true.
Last accessed 28 July.

15. MULTAQ U.S. Prescribing information
products.sanofi-aventis.us/Multaq/Multaq.pdf. Last accessed 28 July.

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Media Contact: Ingrid Görg-Armbrecht, +33-1-53-77-46-25 or +33-6-38-10-50-87, ingrid.goerg-armbrecht at sanofi-aventis.com