STALLERGENES: Continued Dynamic Growth / Cumulative Sales to the end of September 2009 up 12%

ANTONY, France -

Million EUR 2008 2009 09/08 EURm % Sales EURm % Sales Var.% Southern Europe (1) 23.8 70 26 68 9 Other EU countries (2) 8.6 25 10.3 27 20 Other markets 1.8 5 1.9 5 8 SLIT 26.3 77 30.5 79 16 SCIT 6.5 19 6.3 17 (2) Other products 1.4 4 1.4 4 0 Total Q3 sales 34.2 100 38.2 100 12 Million EUR 2008 2009 09/08 EURm % Sales EURm % Sales Var.% Southern Europe (1) 88.6 74 96.3 71 9 Other EU countries (2) 27.2 22 34.4 25 27 Other markets 5.5 4 5.2 4 (5) SLIT 97.6 81 111.6 82 14 SCIT 18.8 15 19.1 14 2 Other products 4.8 4 5.2 4 7 Cumulated Sales 121.2 100 135.9 100 12 (1) Potugal,Spain,France,Italy,Greece; (2) Switzerland included

Sales performance and financial position

Sales grew at a rate equal to that of the first half year, which was 3 points higher than the growth in the 2nd quarter 2009. This dynamic remained driven, as in the 1st half year, by the markets of Northern Europe (”Other EU countries”) and the sublingual route, which maintained double digit growth rates. This performance must be highlighted against the background of an unfavourable base effect, of strong growth recorded in the 3rd quarter 2008 (+17%).

Organic growth, both in quarterly and cumulative data and restated for the currency effect was 11%.

Net debt at the end of September 2009 was down by 18% compared to the end of September 2008.

Significant transactions and events in the quarter

The mutual recognition procedure for Oralair(R) in adult and paediatric indication (desensitising tablet for grass pollen), continued and should lead to obtaining a registration in most European markets by the end of 2009.

Following the positive results of the phase III clinical study with Actair(R) (desensitising tablet for dust mites) in adults, an application for a phase III clinical study for children in respect of 450 patients was filed in Europe and the registration strategy for Actair(R) for adults is currently being defined.

Stallergenes announced on 16 September positive preliminary results for a phase IIb/III clinical study carried out on allergic rhinitis to birch pollen using a recombinant allergen as active ingredient. The confirmation phase III study should be carried out during the 2011 pollen season.

Outlook for current year

The good level of sales to the end of September now leads to guidance of growth of 10% or slightly greater for 2009. Given this outlook, Stallergenes expects net profit to be close to that of the previous year. Lastly, the last quarter will be marked by the publication in December of three important phase III clinical results on Oralair(R):

- the US study on adult indication, - the 3rd year of a long-term study, - the study for the optimisation of protocols.

The preliminary results of a phase III study on Staloral(R) dust mites in asthma carried out in China will also be published.

About Stallergenes

Stallergenes is a European biopharmaceutical laboratory specialising in the treatment by desensitisation of allergy-related respiratory conditions, such as rhino conjunctivitis or allergic asthma. A pioneer and a leader in desensitisation treatments by sublingual administration, Stallergenes dedicates 21% (gross) of its sales to its Research and Development activities, which are primarily directed at developing a new therapeutic range enabling the provision of desensitisation treatments by sublingual tablets.

Stallergenes realised 2008 sales of EUR 171 million, with over 500,000 patients treated with Stallergenes desensitisation products.

Stallergenes trades on Compartment B of the Euronext Paris Stock Exchange and is a component of the SBF 120 index. ISIN Code: FR0000065674 Reuters Code: GEN.PA Bloomberg Code: GEN.FP

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

Source: Stallergenes

Contacts: Albert Saporta, Chairman, Tel. +33-1-55-59-20-04, Christian Thiry, Chief Financial Officer, Tel. +33-1-55-59-20-95, e-mail: investorrelations 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; Stallergenes Press Relations, Lise Lemonnier, Communication officer, Tel. +33-1-55-59-20-96, e-mail: llemonnier at stallergenes.fr