argenx announces launch of proposed initial public offering in the United States

Regulated information

8 May 2017

Breda, the Netherlands / Ghent, Belgium - argenx (Euronext Brussels: ARGX), a clinical-stage biotechnology company developing a deep pipeline of differentiated antibody-based therapies for the treatment of severe autoimmune diseases and cancer, announced today that it intends to offer and sell, subject to market and other conditions, 3.6 million American Depositary Shares ("ADSs") representing 3.6 million ordinary shares in an initial public offering in the United States (the "Offering").

The final issuance price per ADS (in USD) sold in the Offering will be determined following the bookbuilding process. Each of the ADSs offered in the Offering represents the right to receive one ordinary share.

argenx`s ordinary shares are currently listed on the regulated market of Euronext Brussels. argenx has made an application to have its ADSs listed on the NASDAQ Stock Market under the symbol "ARGX". Application will also be made to admit the ordinary shares issued pursuant to the Offering to trading on the regulated market of Euronext Brussels.

A registration statement relating to and describing the terms of the Offering has been filed with the U.S. Securities and Exchange Commission but has not yet become effective. The ADSs may not be sold, nor may offers to buy be accepted, prior to the time the registration statement becomes effective.

Cowen and Company and Piper Jaffray & Co. are acting as joint bookrunning managers for the Offering, and JMP Securities and Wedbush PacGrow are acting as co-managers. Kempen & Co is acting as argenx`s advisor in connection with the Offering.

argenx intends to grant the underwriters of the Offering a 30-day option to purchase additional ordinary shares in the form of ADSs, provided that the number of such additional ADSs shall not exceed 15% of the ADSs sold in the Offering.

The ADSs referred to in this release are to be offered only by means of a prospectus. When available, copies of the preliminary prospectus can be obtained from Cowen and Company, LLC, c/o Broadridge Financial Services, 1155 Long Island Avenue, Edgewood, NY 11717, Attn: Prospectus Department, by telephone at (631) 274-2806 or by fax at (631) 254-7140 or from Piper Jaffray & Co., Attn: Prospectus Department, 800 Nicollet Mall, J12S03, Minneapolis, MN 55403, or by telephone at (800)747-3924, or by email at prospectus@pjc.com.

This press release is for information purposes only and does not constitute, and should not be construed as, an offer to sell or the solicitation of an offer to buy or subscribe to any securities, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale is not permitted or to any person or entity to whom it is unlawful to make such offer, solicitation or sale. Reference is also made to the restrictions set out in "Important information" below. This press release is not for publication or distribution, directly or indirectly, in or into any state or jurisdiction into which doing so would be unlawful or where a prior registration or approval is required for such purpose.