argenx SE

Regulatory Filings • Feb 18, 2016

argenx opens clinical trial sites in South Korea for ARGX-111 program

Breda, the Netherlands/Ghent, Belgium, 18 Febr 2016 - argenx (Euronext Brussels: ARGX), a clinical-stage biopharmaceutical company focused on creating and developing differentiated therapeutic antibodies to treat cancer and severe autoimmune diseases, today announced the opening of three clinical trial sites in South Korea for the recruitment of METamplified cancer patients for the Phase 1 safety expansion cohort of ARGX-111.

"The prevalence of cancer patients with MET-amplification is higher in Asia so we are very excited to have opened these clinics to facilitate the recruitment process into the ARGX-111 program", commented Tim Van Hauwermeiren, CEO at argenx. "Expanding our clinical trials into Asia is the first step towards increasing our presence in this region and becoming a globally active company. We hope this strategy will allow us more diverse enrollment capabilities and the possibility of new collaborations."

The new Phase 1 sites will open in Seoul, South Korea and include the international renowned Samsung Medical Center, Seoul National University Hospital and Asan Medical Center. Five clinical trial sites are already open in Europe, specifically in Belgium and France. Opening of these sites supports the further development of ARGX-111 in MET-amplified malignancies.

About ARGX-111

ARGX-111 is a Met-targeting human monoclonal SIMPLE Antibody(TM) that modulates all known mechanisms of action of the receptor. ARGX-111 benefits from POTELLIGENT® enhanced Antibody Dependent Cellular Cytotoxicity (ADCC), which drives the immune system to destroy

c-MET positive cells of the primary tumor and the circulating tumor cells that are responsible for metastasis; and from NHance®, which drives tissue penetration in the hunt for tumor metastasis. This unique combination results in a potentially best-in-class drug candidate for c-Met therapies. ARGX-111 is tested in a Phase 1 safety expansion cohort in MET-amplified patients.

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.

www.argenx.com

For further information, please contact:

Joke Comijn, Corporate Communications Manager +32 (0)477 77 29 44 +32 (0)9 243 40 70 info@argenx.com

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

Beth DelGiacco (US IR) Stern Investor Relations +1 212 362 1200 beth@sternir.com

Forward-looking Statements

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