First Quarter 2023 Financial Results and Business Update May 4, 2023

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Continued Progress Across Business Reaching More gMG Patients Broaden Immunology Pipeline Geographic Expansion $218M in global product revenues in first quarter 2023 5 Global VYVGART Approvals US, Japan, EU, UK and Israel Planned SC Approval June 20th PDUFA Date Five Data Readouts CIDP, ITP, PV, POTS, MMN Pioneer FcRn Class of Medicines 3 ARGX-117 and ARGX-119 Advancing to clinical proof-of-concept

Redefining What ‘Well-Controlled’ Means for the Patient Achieve minimal symptom expression Reduce reliance on broad immunosuppressants Regain control of their lives, including professionally and socially Minimize treatment burden We want to transform gMG treatment for patients 4

CIDP 16K BP* 52K PC-POTS >500K Steady Cadence of Upcoming Data Readouts 2023 DATA READOUTS Mid-2023 Fourth Quarter 2023 Myositis* 63K Pemphigus 19K ITP 57K ARGX-117 Patient numbers are U.S. prevalence from argenx market research *GO/NO GO Decisions. 2024 DATA READOUTS 2024 MMN 6K Efgartigimod clinical July 2023 5

ARGX-117: First Clinical Efficacy Data Expected Mid-2023 MMN: Interim Phase 2 Data Expected Mid-2023 2024 DATA READOUTS ARGX-117: Sweeping Antibody Broaden immunology pipeline clinical Confirm safety profile in MMN patients Measure extent of complement blockade with initial dose scheme Build PK/PD model to guide selection for Phase 3 dose Confirm efficacy signal in MMN patients Delayed graft function in kidney transplant POC trial to start 2H23 Dermatomyositis POC trial to start by end of 2023 6 Optimal recycling pH and Ca2+ switch No effector function

ARGX-119: MuSK Agonist with Broad Potential in Neuromuscular Disease 10 dose cohorts 3 dose cohorts/4 weekly doses Congenital Myasthenic Syndrome (CMS) First-in-Patient Single Ascending Dose Multiple Ascending Dose First-in-patient trial in CMS to serve as proof of biology Translational work ongoing in amyotrophic lateral sclerosis (ALS) First-in-Human Phase 1 Healthy Volunteer Study Broaden immunology pipeline clinical 7

75 131 173 218 (in millions of $) Q1 2023 Q4 2022 QoQ % Growth* US 196 159 23% Japan 10 8 16% Europe 10 5 82% Other** 2 1 168% Total 218 173 25% $218M Total Q1 2023 Product Net Sales 2023 DATA READOUTS Breakdown by Region * QoQ growth % reflects operational growth, excluding any impact from changes in fx. ** The product net sales relate to sales made outside of US, Japan and Europe and relates to named patient sales made with the US label. First Quarter 2023 Revenue Update 21 Q1 2022 Q2 2022 Q3 2022 Q4 2022 Q1 2023 8

First Quarter 2023 Financial Results Three months ended March 31 (in millions of $) 2023 2022 Product net sales 218 21 Collaboration revenue and other 12 10 Total operating income 230 31 Cost of sales (18) (1) R&D expenses (166) (152) SG&A expenses (149) (101) Total operating expenses (334) (254) Operating loss for the period (104) (223) Financial income / (expenses) 28 (7) Loss for the period before tax (76) (230) Tax 47 3 Loss for the period (29) (227) Three Months Ended Ended first quarter 2023 with cash of $2B Financial income / (expenses) includes financial income / (expenses) and exchange gains / (losses) Cash reflects cash, cash equivalents and current financial assets. 9

Humility Innovation Excellence We are on a Co-Creation Empowerment bold mission Transforming the lives of patients with severe autoimmune disease through immunology innovation 10

Payors Optimizing Core Launch Strategies Driving physicians to prescribe in earlier line therapies VYVGART launched in US, Japan and Germany Broadest offering to gMG community, providing more choice to patients 11 Early engagement with payors to enable access for patients SUBMISSIONS IN 10+ COUNTRIES 90% US VYVGART POLICIES FAVORABLE SC or IV Fixed or flexible dosing Next-generation PFS 50% of patients have IVIg experience Patients Physicians Payors

Global gMG Launch Progressing 12 United States Global VYVGART Approved December 2021 SC Efgartigimod PDUFA June 20, 2023 Japan Approved January 2022 Europe Approved September 2022 China (Zai Lab) Expected approval in 2023 Canada Expected approval in 2023 United Kingdom Approved March 2023 Israel (Medison) Approved April 2023 SC efgartigimod approval decisions expected in Europe and Japan by 1Q24

Lead with Compassion for our Patients Drive Impact Through Innovation Pioneer with Our Science Build the Company We Want to Work For argenx 2025: A Leading, Sustainable Immunology Company …and gMG is just the beginning 13