Stallergenes Welcomes Ares Life Sciences as a New Reference Shareholder

ANTONY, France, November 10, 2010 - Following the announcement that Wendel had entered exclusive
negotiations with Ares Life Sciences on October 28, 2010, with a view to
selling its entire stake (around 46%) in Stallergenes, the company's Works
Council met on November 10, 2010.

Stallergenes' Works Council having returned a positive
consultative opinion at this meeting, Wendel and Ares Life Sciences proceeded
to sign a firm transfer agreement.

It is in this context that the Stallergenes Board of Directors
met today. It took note of Ares Life Sciences' intention to pursue the
development of Stallergenes from the company's French industrial footprint
(production units and R&D centre in Antony and Amilly), accelerate the
execution of the company's strategic roadmap, as well as further support its
international development, notably in the US. The Stallergenes Board of
Directors took also note that Ares Life Sciences does not foresee any change
within Stallergenes' jobs, salary or human resources policies.

During the meeting, Stallergenes' Chairman and CEO, Albert
Saporta, has declared: "The Ares Life Sciences team, which has already
enjoyed some major successes on the European and American pharmaceutical
markets, has a thorough understanding of the issues related to our sector and
supports our entrepreneurial vision. This expertise will be of great benefit
to the company in its current expansion phase".

The Board of Directors also took note of the resignation of
four of its directors (Messrs. David Darmon, Arnaud Fayet, Dirk-Jan Van
Ommeren and Compagnie Financiere de la Trinite) and decided to co-opt Mrs
Paola Ricci and Messrs Jacques Theurillat, Patrick Lee, and Christian Chavy
to replace them. These changes of board directors remain subject to the
completion of the sale of Wendel's stakeholding in Stallergenes to Ares Life
Sciences.

Given the absence of any conflict of interest with respect to
the planned sale, the Board members also decided to appoint the accountancy
firm Ledouble SA as an independent expert with a view to issuing a fairness
opinion in the context of the takeover bid that Ares Life Sciences will
submit regarding the totality of Stallergenes' shares in application of the
regulations in force. This appointment will come into force on the date of
transfer of Wendel's stakeholding.

Stallergenes and Ares Life Sciences' management teams will
hold a joint telephone conference on Wednesday November 17 at 6 p.m. to
answer questions related to this change in shareholding.

In application of the provisions of the AMF's General
Regulations, the Board of Directors may publish its opinion on the value of
the said takeover bid or its consequences for Stallergenes, its shareholders
and its employees on the internet once the planned bid has been submitted to
the market authority.

About Stallergenes

Stallergenes is a European biopharmaceutical company dedicated
to immunotherapy treatments for the prevention and treatment of
allergy-related respiratory diseases, such as allergic rhinoconjunctivitis,
rhinitis and asthma.

A pioneer and leader in sublingual immunotherapy treatments,
Stallergenes dedicates more than 20% of its turnover, in gross terms, to
Research and Development and is actively involved in the development of a new
therapeutic class: sublingual immunotherapy tablets. In 2009, Stallergenes
had a turnover of 193 million euros and more than 500,000 patients were
treated with Stallergenes' immunotherapy products.

    Euronext Paris (Compartment B)
    SBF 120.
    ISIN code: FR0000065674
    Reuters code: GEN.PA
    Bloomberg code: GEN.FP

    For further information, please visit our website:
    www.stallergenes.com

Contacts: Albert Saporta - Chairman and CEO., Tel: +33-1-55-59-20-04; Christian Thiry - Financial Director, Tel: +33-1-55-59-20-95, e-mail: investorrelations at stallergenes.fr; Press relations: Lise Lemonnier - Communication Manager, Tel: +33-1-55-59-20-96, e-mail: llemonnier at stallergenes.fr; Investor and analyst relations: Lucile de Fraguier - Pavie Finance, Tel: +33-1-42-15-04-39, e-mail: contact at pavie-finance.com