STALLERGENES 2009 : Further Profit Margin Growth and Significant Cash Generation Further Profit Margin Growth and Significant Cash Generation:

ANTONY, France, March 16, 2010 -

    - Sales up 13%, Operating Profit up 15%, Net Profit up 17%
    - Record Free Cash Flow of EUR 17.5 Million (x 3.7)
    - Net Cash Position Turned Positive
    - Proposed Dividend of 0.55 EUR (up 22%)

The Board of Directors' meeting of 15 March 2010, chaired by
Albert SAPORTA, approved the 2009 consolidated financial statements:

    In millions d'Euros        2008      08-Jul     2009          09-Aug
                                     %    Var.%             %      Var.%
    Sales                170,9    100,0      16    192,8   100,0      13
    Cost of goods sold   (39,8)   (23,3)     21    (43,1)  (22,3)      8
    SG&A                 (72,9)   (42,7)     12    (78,9)  (40,9)      8
    R&D costs            (36,6)   (21,4)     25    (46,2)  (24,0)     26
    R&D revenues           6,6      3,9      20      7,6     3,9      14

    EBIT                  28,1     16,5      11     32,2    16,7      15
    Net result, group
    share                 19,0     11,1      17     22,2    11,5      17

    EBITDA                34,3     20,1      14     39,7    20,6      16

    Capital
    expenditure           18,3     10,7      12     16,0     8,3     -12
    Working capital       14,9      8,7      37     12,9     6,7     -13
    Free cash flow         4,7      2,8     -28     17,5     9,1     272
    Net financial          9,6               -8     (4,9)           -151
    debts(Net cash)
    Equity                82,6               24    102,7              24
    Headcount, end of      782               13      873              12
    year
    EPS, diluted      EUR 1,43               17 EUR 1,69              18
    Dividend per
    share             EUR 0,45               13 EUR 0,55              22

2009: significant increase in profitability and financial
position indicators

- Profitable growth to finance the Group's long-term expansion

The 2009 sales growth dynamics (up 13%, 12% organic) as well
as strict control on operating expenses (63.2% of sales vs 66.0% in 2008,
before R&D) enabled the Group to both absorb research efforts (up 26%,
representing 24% - gross - of sales) and further improve profit margins:
operating profit totalled EUR 32.2 million, that underlined an operating
profit margin of 16.7% (16.5% in 2008). Net profit grew for the ninth
consecutive year by 17% to EUR 22.2 million, generating an 11.5% net profit
margin (11.1% in 2008).

- A particularly sound financial position

Well-controlled capital expenditure and working capital requirements
generated a record free cash flow of EUR 17.5 million (x 3.7 compared to
2008). Net debt declined by EUR 14.5 million. The Group reports a positive
year-end net cash position for the first time in 10 years, amounting to EUR
4.9 million.

The audit procedures have been performed. As soon as the
management report will have been reviewed, the audit report will be issued.
The Group's 2009 consolidated financial statements are available from the
Group's website: www.stallergenes.com.

2010 outlook

The laboratory is focusing its efforts on bringing Oralair(R)
to market, after it was granted a marketing authorisation in 22 European
countries in November 2009, on the registration of Actair(R) in Europe and on
the partnerships it put into place to roll out Stalair(R) products
internationally over the medium term.

Due to the effects of the economic crisis and the cost cutting
steps taken by health authorities, our 2010 sales guidance was revised
downwards. Nonetheless, Stallergenes expects further growth of sales in
excess of 8%. Against this background, the laboratory set itself the
objective of increasing its margins, bearing in mind that the greater part of
the cost of the Oralair(R) grasses study in the US had been incurred by end
2009. The results of this study will be known and released within the next
few weeks.

Significant recent transactions and events

The new research and control laboratories have been completed:
Stallergenes invested EUR 28 million in equipment over the past 5 years to
put in place the Stalair(R) programme pharmaceutical platform, which is now
fully operational.

Dividend

In order to demonstrate its confidence in the Group's
development outlook, the Board of Directors will propose to the General
Meeting to be held on 28 May 2010, the distribution of a dividend of EUR 0.55
per share, reflecting a 22% increase over the previous year .

OSRD eligibility

As of 26 March 2010, Stallergenes will be eligible for the
OSRD compartment (Euronext Paris deferred settlement service). This system,
which enables both institutional and individual investors to use leverage to
buy or sell shares, while being regulated by strict prudent rules, should
increase share liquidity.

ABOUT STALLERGENES

Stallergenes is a European biopharmaceutical laboratory
specialising in treatments by immunotherapy for the prevention and treatment
of allergy-related respiratory conditions, such as rhino conjunctivitis,
rhinitis and allergic asthma. Stallergenes is ranked seventh among French
pharmaceutical laboratories[1]. A pioneer and a leader in immunotherapy
treatments by sublingual administration, Stallergenes dedicates more than 20%
(gross) of its sales to its Research and Development activities, which are
primarily directed at developing a new therapeutic range enabling the
provision of immunotherapy treatments by sublingual tablets.

Stallergenes reported 2009 sales of EUR 193 million, with over
500,000 patients treated with Stallergenes desensitisation products.

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

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

[1] Laboratories marketing products licensed as pharmaceutical
specialties

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 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