ANTONY, France, July 15 --

Million EUR 2008 08/07 2009 09/08 MEUR %Sales Var.% MEUR %Sales Var.% Southern
Europe (1) 26.7 71 15 28.5 68 7 Other EU countries (2) 9.3 24 20 11.4 28 23
Other markets 2.0 5 47 1.5 4 (23) SLIT 30.3 80 21 33.8 82 12 SCIT 6.1 16 7 5.9
14 (3) Other products 1.6 4 4 1.7 4 9 Q2 sales 38.0 100 18 41.4 100 9 Southern
Europe (1) 64.7 75 15 70.3 72 9 Other EU countries (2) 18.6 21 18 24.1 25 30
Other markets 3.7 4 46 3.2 3 (12) SLIT 71.3 82 19 81.0 83 14 SCIT 12.3 14 4 12.8
13 4 Other products 3.4 4 6 3.8 4 10 H1 sales 87.0 100 16 97.6 100 12 (1)
Portugal, Spain, France, Italy, Greece; (2) Switzerland included

HY1 sales

2nd quarter growth remained high at 9% (organic* 8%), but slowed down compared
with the very strong start of the year. Sales growth over the first half-year
remained strong at 12% (organic 11%), reflecting the continuing breakthrough of
the sublingual route (+14%), which represented 83% of total sales.

The analysis by geographic region highlights the sharp increase of Other EU
countries to 30% of sales, primarily due to the successful launch of Oralair(R)
and the price increases introduced in Germany, as well as the transfer of the
operations to a subsidiary in Switzerland.

Growth was more moderate in Southern Europe (up 9%). In addition to the
consequences of weak pollen seasons in 2008, these markets appeared more
affected by the economic crisis in a context of partial reimbursement (Italy and
Spain).

The decline in Other markets, a very diverse group whose performance is
volatile, was mostly due to exceptional 2008 sales and foreign exchange effects.

HY1 highlights

5 years of research were rewarded in the 1st half-year 2009 with the positive
results of the phase III clinical study carried out on the house dust mite
desensitization tablet.

Moreover, the mutual recognition procedure for Oralair(R) (grass pollen
desensitization tablet) started at an operational level and should lead to
registration in most European countries by the end of 2009.

Outlook

The 1st half-year 2009 financial results, to be published on 26 August next
after close of trading, should report a slight improvement over the 1st
half-year 2008.

We confirm our previously issued full-year guidance of sales growth of about
10% and an operating profit maintained at the same high level as 2008, against a
background of strong accompanying RD investments.

Lastly, the second half-year will be marked by a particularly busy news flow: 3
Oralair(R) phase III studies (US, 3rd year of long-term study, protocol
optimization), 1 phase IIb/III study on the birch pollen desensitization tablet,
which for the first time includes a recombinant allergen, and 1 phase III
Staloral(R) study on asthma, carried out in China.

Shareholders’ agenda

The 2009 first half-year results will be presented on 27 August 2009 at 11.30am
CET at Le Bristol hotel, 112, rue du Faubourg Saint-Honore, 75008 Paris, France.

A webcast of the meeting will be available both in French and English from 3pm.

ABOUT STALLERGENES

Stallergenes is a European biopharmaceutical company dedicated to
desensitization therapies for the prevention and treatment of allergy-related
respiratory diseases, e.g. rhinoconjunctivitis and allergic asthma. A pioneer
and leader in sublingual desensitization treatments, Stallergenes devotes 21%
(gross) of its sales to Research and Development and is actively involved in the
development of a new therapeutic class: sublingual desensitization tablets.

In 2008, Stallergenes had sales of EUR 171 million and provided desensitization
treatments to more than 500,000 patients.

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

Additional financial information is available at: http://www.stallergenes.com

* Excluding foreign exchange effects

SOURCE: Stallergenes

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