arGEN-X Raises Additional €1.8 million via Exercise of Over-allotment Option and Announces the End of the Stabilization Period in relation to its Initial Public Offering

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Regulated Information 

Total Gross Proceeds from Initial Public Offering Increase to €41.8 million

11 August 2014

Breda, the Netherlands / Ghent, Belgium - arGEN-X N.V. ("arGEN-X", Euronext Brussels: ARGX), a clinical-stage biopharmaceutical company focused on creating and developing differentiated therapeutic antibodies for the treatment of cancer and severe autoimmune diseases, announces today the partial exercise of the over-allotment option by KBC Securities (the "Stabilization Manager") acting on behalf of KBC Securities and Kempen & Co (the "Joint Global Coordinators") and Petercam (the "Co-Lead-Manager"); and the end of the stabilization period, in relation to its Initial Public Offering that ended on 8 July 2014 (the "IPO").

arGEN-X had granted the Stabilization Manager an option to purchase up to 470,589 additional shares at the Offer Price of €8.50 to cover potential over-allotments or short positions in connection with the IPO, which was exercisable for a period of 30 calendar days as from the first day of trading of the shares on Euronext Brussels (i.e. 10 July 2014).

On 8 August 2014 KBC Securities exercised the over-allotment option for 208,725 shares, raising additional gross proceeds of €1.8 million for arGEN-X. 

As a result, the total number of shares sold by arGEN-X in the IPO amounts to 4,914,607 shares, representing total gross proceeds of € 41.8 million for arGEN-X.

The stabilization period commenced on 10 July 2014 and ended on 9 August 2014. Details of the stabilization activity carried out by the Stabilization Manager are available in appendix A.

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About arGEN-X

arGEN-X is a clinical-stage biopharmaceutical company focused on creating and developing differentiated therapeutic antibodies for the treatment of cancer and severe autoimmune diseases. arGEN-X has generated a pipeline of differentiated clinical and preclinical antibody candidates using its SIMPLE Antibody(TM) discovery platform. SIMPLE Antibody(TM) has a particular strength in addressing novel, complex disease targets that are difficult to access using established antibody technology platforms. Proprietary Fc engineering technologies (NHance® and ABDEG(TM)) and POTELLIGENT® technology (licensed from BioWa, inc.) further enhance the therapeutic properties of SIMPLE Antibody(TM) leads in terms of tissue penetration/residence time in the body, ability to clear disease targets or pathogenic antibodies and cell-killing potency through Antibody-Dependent Cell-mediated Cytotoxicity (ADCC), respectively. arGEN-X has leveraged its suite of antibody technologies in forging strategic collaborations with pharmaceutical and biotechnology companies to provide new approaches to diseases with unmet medical needs.

arGEN-X is listed on the Euronext Brussels exchange under the symbol ARGX.

www.arGEN-X.com

SIMPLE Antibody(TM), NHance® and ABDEG(TM) are trademarks of arGEN-X NV
POTELLIGENT® is a trademark of BioWa Inc.

For further information, please contact:

Tim Van Hauwermeiren, Chief Executive Officer
Eric Castaldi, Chief Financial Officer
+32 (0)9 243 40 70
info@arGEN-X.com

Mark Swallow/David Dible
Citigate Dewe Rogerson
+44 207 282 2948
arGEN-X@citigatedr.co.uk

KBC Securities, Kempen & Co, Petercam and Wedbush PacGrow Life Sciences have been acting for arGEN-X and no one else in relation to the Initial Public Offering, and will not be responsible to anyone other than arGEN-X for providing the protections offered to their respective clients nor for providing advice in relation to the Initial Public Offering.

arGEN-X assumes responsibility for the information contained in this announcement. None of KBC Securities, Kempen & Co, Petercam or Wedbush PacGrow Life Sciences or any of their respective directors, officers, employees, advisers or agents accepts any responsibility or liability whatsoever for or makes any representation or warranty, express or implied, as to the truth, accuracy or completeness of the information in this announcement (or whether any information has been omitted from the announcement) or any other information relating to arGEN-X its respective subsidiaries or associated companies, whether written, oral or in a visual or electronic form, and howsoever transmitted or made available or for any loss howsoever arising from any use of announcement or its contents or otherwise arising in connection therewith.

The information contained in this announcement is for background purposes only and does not purport to be full or complete.

No representation or warranty, express or implied, is given by or on behalf of arGEN-X or any of its affiliates as to the accuracy or completeness of the information or opinions contained in this announcement, and no liability is accepted for any such information or opinions.

This announcement does not constitute, or form part of, an offer or invitation to sell or issue, or any solicitation of an offer to purchase securities and any purchase of, or application for, shares in arGEN-X.

In connection with its Initial Public Offering, arGEN-X has published a prospectus, which is available on www.argen-x.com and contains certain detailed information about arGEN-X and its business, management, risks associated with investing in arGEN-X, as well as financial statements and other financial data.

This announcement does not constitute or form part of an offer or solicitation to purchase or subscribe for new shares in the capital of arGEN-X in the United States, Australia, Canada, South-Africa, Japan or any jurisdiction in which such an offer or solicitation is unlawful. In particular, the new shares referred to in this Announcement have not been, and will not be, registered under the U.S. Securities Act of 1933 (the "Securities Act") or under the securities legislation of any state of the United States, and may not be offered, sold, resold or delivered, directly or indirectly, in or into the United States absent registration except pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the Securities Act. No public offering of securities of arGEN-X will be made in connection with the Initial Public Offering in the United States, Australia, Canada, South Africa, Japan or elsewhere.

This communication is directed only at (i) persons who are outside the United Kingdom or (ii) persons who have professional experience in matters relating to investments falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005 (the "Order") and (iii) high net worth entities, and other persons to whom it may lawfully be communicated, falling within Article 49(2) (A) to (D) of the Order (all such persons together being referred to as "relevant persons"). Any investment activity to which this communication relates will only be available to and will only be engaged in with, relevant persons. Any person who is not a relevant person should not act or rely on this document or any of its contents.

This communication may be distributed in a member state of the European Economic Area, with the exception of Belgium, which applies Directive 2003/71/EC and amendments thereto, including Directive 2010/73/EU (this Directive together with any implementing measures in any member state, the "Prospectus Directive") only to those persons who are investment professionals for the purposes of the Prospectus Directive in such member state, and such other persons as this document may be addressed on legal grounds, and no person that is not a relevant person may act or rely on this document or any of its contents.

Appendix A