argenx to Host Conference Call & Webcast to Report Fourth Quarter Business Update and Full Year 2015 Financial Results on 11 March 2016

Breda, the Netherlands / Ghent, Belgium – argenx (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, today announced it will host a conference call and audio webcast on Friday, 11 March 2016 at 3:00 pm CET (9:00 am ET) to discuss the 2015 financial results, as well as provide a fourth quarter business update.

To participate in the conference call, please select your phone number below, and use the confirmation code 61559035. The webcast may be accessed on the homepage of the argenx website at www.argenx.com or by clicking here.

A replay of the webcast will also be available at the argenx website.

About argenx

argenx combines the diversity of the llama immune system with antibody engineering to advance a clinical pipeline to treat patients with cancer and autoimmune diseases. Our platforms allow us to unlock novel and complex targets and develop antibody-based drugs designed for greater efficacy and longer duration of effect. The strength of our team, our deep understanding of the biology, and our committed collaborations with industry leaders contribute to the success of our journey.

argenx is listed on the Euronext Brussels exchange under the symbol ARGX.

www.argenx.com

Participant Free Call Dial-In Numbers:

UK

0800 694 0257

Participant Standard International Dial-In:

UK Standard International

+44 (0) 1452 555 566

Participant UK Local Call Dial-In Numbers:

UK

0844 493 3800

UK National Call

0871 700 0345

Participant Local Call Dial-In Numbers:

Australia

0290 371 687

Austria

0192 865 68

Belgium

0817 000 61

Croatia

0177 766 11

Czech Republic

2288 804 60

Denmark

3272 7625

Finland

0923 195 187

France

0176 742 428

Germany

0692 222 3479

Germany

0692 222 4918

Hungary

0618 088 303

India

0223 098 5304

Ireland

0143 196 48

Ireland

0150 601 53

Italy

0236 008 146

Latvia

6778 2516

Luxembourg

2088 0695

Netherlands

0207 176 886

New Zealand

0992 917 07

Norway

2156 3013

Poland

2230 701 18

Romania

0318 144 957

Russia

4996 771 036

Slovenia

0160 093 64

South Africa

2110 032 02

Spain

9141 436 69

Sweden

0850 336 434

Switzerland

0565 800 007

USA

1631 510 7498

Participant Free Call Dial-In Numbers:

Argentina

0800 666 3294

Australia

1800 020 199

Austria

0800 005 311

Belgium

0800 408 64

Brazil

0800 891 4606

Bulgaria

0080 011 002 42

Canada

1866 966 0399

Chile

1230 020 7879

Columbia

0180 051 806 20

Cyprus

8009 5227

Czech Republic

8001 429 02

Denmark

8088 8464

Egypt

0800 000 0318

Estonia

8000 100 167

Finland

0800 112 363

France

0805 632 056

Germany

0800 101 4960

Greece

0080 012 6060

Hong Kong

8009 687 77

Hungary

0680 016 203

Iceland

8009 794

India

0008 001 006 741

Indonesia

1803 044 113 24

Ireland

1800 932 187

Israel

1809 216 057

Italy

8009 874 96

Japan

0066 331 324 75

Latvia

8000 3337

Luxembourg

8002 7512

Malaysia

1800 814 521

Mexico

0018 665 203 144

Monaco

8009 3519

Netherlands

0800 023 5091

New Zealand

0800 448 423

North China

1080 071 218 19

Norway

8001 9414

Philippines

1800 111 011 58

Poland

0080 012 126 55

Portugal

8008 120 40

Romania

0800 895 055

Russia

8108 002 097 2044

Russia

8800 115 6818

Singapore

8001 203 988

Slovakia

0800 001 418

Slovenia

0800 801 74

South Africa

0800 980 759

South China

1080 012 018 13

South Korea

0079 844 312 22

Spain

8000 995 39

Sweden

0200 890 171

Switzerland

0800 828 006

Taiwan

0080 112 6902

Thailand

0018 004 421 39

Turkey

0080 014 203 8193

UAE

8000 357 030 30

USA

1866 966 9439