new title slide

July 20, 2021

Welcome & Introductions

Beth DelGiaccoVice President, Corporate Communications & Investor Relations

Forward Looking Statements

Safe Harbor: Certain statements contained in this presentation, other than present and historical facts and conditions independently verifiable at the date hereof, may constitute forward-looking statements. Examples of such forward-looking statements include those regarding the therapeutic and commercial potential of our product candidates; our clinical development and regulatory plans, including the timing, design and outcome of ongoing and planned clinical trials and preclinical activities; the timing, progress and benefits of commercialization activities; our plans to start registrational trials this year; our statements regarding new assets yearly from IIP; our statements regarding potential and effect of efgartigimod; our expectation to have IND filing this year; our plan to start Phase 2 trial in MMN this year; and the expected size of the markets for our product candidates. When used in this presentation, the words “anticipate,” “believe,” “can,” “could,” “estimate,” “expect,” “intend,” “is designed to,” “may,” “might,” “will,” “plan,” “potential,” “predict,” “objective,” “should,” or the negative of these and similar expressions identify forward-looking statements.Such statements, based as they are on the current analysis and expectations of management, inherently involve numerous risks and uncertainties, known and unknown, many of which are beyond the Company’s control. Such risks include, but are not limited to: the impact of COVID-19 pandemic on our business, the impact of general economic conditions, general conditions in the biopharmaceutical industries, changes in the global and regional regulatory environments in the jurisdictions in which the Company does or plans to do business, market volatility, fluctuations in costs and

changes to the competitive environment. Consequently, actual future results may differ materially from the anticipated results expressed in the forward-looking statements. In the case of forward-looking statements regarding investigational product candidates and continuing further development efforts, specific risks which could cause actual results to differ materially from the Company’s current analysis and expectations include: failure to demonstrate the safety, tolerability and efficacy of our product candidates; final and quality controlled verification of data and the related analyses; the expense and uncertainty of obtaining regulatory approval, including from the U.S. Food and Drug Administration and European Medicines Agency; the possibility of having to conduct additional clinical trials; our ability to obtain and maintain intellectual property protection for our product candidates; and our reliance on third parties such as our licensors and collaboration partners regarding our suite of technologies and product candidates. Further, even if regulatory approval is obtained, biopharmaceutical products are generally subject to stringent on-going governmental regulation, challenges in gaining market acceptance and competition. These statements are also subject to a number of material risks and uncertainties that are described in the Company’s filings with the U.S. Securities and Exchange Commission (“SEC”), including in argenx’s most recent annual report on Form 20-F filed with the SEC as well as subsequent filings and reports filed by argenx with the SEC. The reader should not place undue reliance on any forward-looking statements included in this presentation. These statements speak only as of the date made and the Company is under no obligation and disavows any obligation to update or revise such statements as a result of any event, circumstances or otherwise, unless required by applicable legislation.

Today’s Agenda

Advancing Towards argenx 2025 | Tim Van Hauwermeiren, Chief Executive Officer and Co-Founder

Efgartigimod: Differentiation of our Anti-FcRn Fc Fragment | Hans de Haard, Chief Scientific Officer and Co-Founder

Fifth Efgartigimod Indication: Myositis | Bas van der Woning, Research Fellow

Sixth Efgartigimod Indication: Bullous Pemphigoid | Peter Verheesen, Research Fellow

KOL Panel: Myositis and Bullous Pemphigoid | Moderated by Albert Kovera, Global Marketing• Rohit Aggarwal, MD, MS, University of Pittsburgh Medical Center• Russell Hall, MD, Duke University Medical Center

ARGX-117 Phase 1 Data | New Biology Insights for Multifocal Motor NeuropathyOlivier Van de Steen, Medical Director | Inge Van de Walle, Principal Scientist

Q + A

4

Visit the argenx R&D Day Microsite to View Additional Resources

Myositis and Bullous Pemphigoid

Disease Overview

Patient Stories

MG Experience in China

Discussion on FcRn and Albumin

Relevant Publications

5

Advancing Towards argenx 2025Tim Van HauwermeirenCo-Founder and CEO

Where critical patient need meets breakthrough science

That is where we redefine immunology

2021: Reaching Myasthenia Gravis Patients with EfgartigimodNew modality Only Fc fragment targeting FcRn

Designed ADAPT with patient input

Defined disease biology

Engaging MG community

Correlation of total IgG and MG ADL

8

Efgartigimod: A Precision Tool to Revolutionize Autoimmunity

ITP

Lupus Nephritis

MyastheniaGravis

Myositis

GBS

CIDP

NeuromyelitisOptica

PemphigusAMR

Sjogren’s Syndrome

MembranousNephropathy

ThyroidEye Disease

BullousPemphigoid

IgG

IgG IgG

IgG

9

Myositis: IgG-Mediated Biology

Neuromuscular Disease

Myasthenia Gravis

Chronic Inflammatory Demyelinating

Polyneuropathy

Myositis

AChR, MuSK, LRP4 autoantibodies comprise ~90% of MG patients

40% anti-myelinated peripheral nerve IgGs

Autoantibodies characterized in 70% of patients across IMNM, ASyS and DM

IND filing by end of 2021 pending interactions with FDA

ADHEREGO/NO-GO

+ ADAPT Data

NextOpportunity

+

+



IMNM: Immune-Mediated Necrotizing Myopathy ASyS: Anti-Synthetase Syndrome DM: Dermatomyositis

Gilhus et al., Nature Rev/Disease Primers. 2019; Gilhus et al., NEJM, 2016; Querol et al., Nat Rev Neurol. 2017; Schmidt, Journal Neuromusc Diseases. 2018; Aquilar-Vazquez et al., Frontiers in Immunology. 2021; McHugh, Managing Myositis. 2019 10

Bullous Pemphigoid: Expanding the Skin Franchise

Pemphigus Pemphigoid

Autoantibody Driven DSG1 and DSG3

Convincing Rationale IVIg, PLEX, Immunoadsorption demonstrate role of IgG

Unmet Patient Needs Fast-acting, tolerable therapies; ability to taper corticosteroids

Autoimmune Blistering Diseases

Primary Endpoint Complete or partial remission off corticosteroids

BP180 and BP230

Registrational trial to start by end of year in parallel to ongoing pemphigus trial

11

Our Pipeline Starts with our Immunology Innovation Program

ANTIBODY ENGINEERING

CLINICAL DEVELOPMENT

First in Class | Unique Design | Multiple Indications

Efgartigimod ARGX-119ARGX-117

Internal Value Creation

LEADING TRANSLATIONAL BIOLOGY LABS

External Value Creation

CusatuzumabLEO

(ARGX-112)Genor

(ARGX-109)AbbVie

(ARGX-115)

ARGX-118AgoMAb

(ARGX-114)Staten

(ARGX-116)Dualyx

12

Neuromuscular Franchise: A Company within a Company

2021 2022 2023 - 2026

MG MG-SC

Myositis

CIDP

MMN

Leveraging infrastructure across multiple indications and molecules

EfgartigimodFcRn antagonist

ARGX-117C2 inhibitor

ARGX-119SIMPLE Antibody™ aimed to boost

the neuromuscular junction in disease

IIP ProgramsMG

CIDP

ALS

MMN

Myositis

SMA

MuSK MG

Congenital MG

13

Efgartigimod in 15 indications (commercial or development)

Global autoimmune market has surpassed $150B

Vibrant neuromuscular, hematology and skin franchises

New asset each year from IIP

Efgartigimod available globally

ARGX-117 in multiple late-stage trials

Building a Leading Immunology Company

Committed to our Patients and their

Communities

Enviable Immunology

Pipeline

Proof-of-concept demonstrated with ARGX-119

Rooted in Science through our IIP

We believe the future belongs to those who collaborate best14

Efgartigimod in 15 indications (commercial or development)

Global autoimmune market has surpassed $150B

Vibrant neuromuscular, hematology and skin franchises

New asset each year from IIP

Efgartigimod available globally

ARGX-117 in multiple late-stage trials

Building a Leading Immunology Company

Committed to our Patients and their

Communities

Enviable Immunology

Pipeline

Proof-of-concept demonstrated with ARGX-119

Rooted in Science through our IIP

We believe the future belongs to those who collaborate best

argenx2025

15

Efgartigimod: Differentiation of our Anti-FcRn FragmentHans de HaardChief Scientific Officer and Co-Founder

FcRn Plays a Key Role in IgG and Albumin Homeostasis

Lysosome

Endothelial Cell

Circulating antibodies are taken up in the cell via pinocytosis. In the endosome, IgG antibodies bind to FcRn1,2

Unbound IgGs enter the lysosomal degradation pathway, while FcRn-bound IgGs are rescued from degradation1,2

The IgG antibodies bound by FcRn are then released back into circulation, thereby extending their half-life1,2

IgG Antibody

IgG Autoantibody

FcRn

Endosome

Studies have shown:

AlbuminAlbumin is recycled by FcRn, independently of IgG

FcRn, neonatal fragment crystallizable receptor; IgG, immunoglobulin G.(1) Sesarman et al., Cell Mol Life Sci. 2010; (2) Habib et al., Supp Neuro Review. 2020.

1

2

3

1

1

2

3

17

Efgartigimod Fc Fragment Binds to FcRn in Same Way as Endogenous IgGs

Efgartigimod binds to FcRn in the same formation as endogenous IgG

Our hypothesis is that different binding properties of FcRn antagonists lead to different subcellular trafficking pathways

Ulrichts et al, Clin Invest. 2018

1 2 3

EndogenousFcRn:IgG

Interaction

Anti-FcRn mAb

18

Efgartigimod Keeps FcRn in its Recycling Path

No treatment Efgartigimod Control anti-FcRn mAb

FcRn over time Normalized Sum Volume (FcRn)

No

rmal

ize

d V

olu

me

(%

)

Time (Min)

19

Albumin Serves a Crucial Role in Lipid Housekeeping

Serum albumin is proposed to enhance cholesterol transport, facilitating steady state levels as cholesterol is metabolized

Inflammatory process Underlying conditions

Low serum albumin levels

Vasodilatory ability ↓ Vascular permeability ↑ Anticoagulation ↓

Cholesterol transport and LDL catabolism

Adverse cardiovascular events

Small molecule binding(toxins & medicines)

Proposed Interactions Between Serum Albumin and CV Outcomes4

(1) Law S, et al. Int J Mol Sci. 2019; (2) Packard CJ, et al. J Lipid Res. 2000; Noto D. et al., Kidney International. 1999; (4) Chien SC, et al. Biomark Res. 2017; (5) Sankaranarayanan S, et al. J Lipid Res. 2013

↓

20

Efgartigimod Blocks IgG Binding to FcRn Without Reducing Albumin

• Potent reduction in IgG levels without decrease in albumin or increase in LDL levels• No albumin decreases observed with chronic dosing out to 34 weeks in Phase 2 pemphigus trial (25mg/kg dose)• Selective blockade of IgG recycling without affecting serum albumin levels is emerging as a key differentiator in the FcRn space• Maintaining levels of human serum albumin is important for lipid housekeeping as well as other key physiological functions

Phase 3 ADAPT Trial of Efgartigimod in Myasthenia Gravis Patients

IgG levels – 1st cycle Albumin and LDL Cholesterol levels – 1st & 2nd cycles

Alb

um

in (

g/L)

Howard et al., The Lancet Neurology. 2021

LDL

(mm

ol/

L)Week Week

21

Efgartigimod: Data Support Favorable Benefit to Risk Ratio

No evidence of dose-limiting toxicities in healthy volunteers or

patients across trials

Opportunity to dose efgartigimod to maximum PD effect

600+ subjects dosed

125+ patients on efgartigimod for

over 12 months

100patients on efgartigimod

for over 18 months

Clinical proof-of-concept in

four indications (MG, ITP, PV, CIDP)

22

Fifth Efgartigimod Indication: MyositisBas van der WoningResearch Fellow

Idiopathic Inflammatory Myopathy (IIM) or Myositis

Rare, severe autoimmune disorders characterized by chronic muscle inflammation, pain and impaired quality of life; no FDA-approved therapies for myositis

MYOSITIS IS MEDIATED BY AUTOANTIBODIES

14 per 100,000

Mid-adult onset

More commonin females

High impact on quality of life: muscle atrophy, pain, functional impairment, dysphagia, dyspnea

High mortality rate: malignancy, interstitial lung disease and infections

No consensus guidelines for management

Treated primarily by rheumatologists and neurologists

Proximal muscle weakness is unifying feature of myositis subsets

PREVALENCE BURDENTREATMENTHALLMARK

Significant market opportunity with ~33K eligible patients in the U.S.

Myositis subsets mediated by autoantibodies: immune-mediated necrotizing myopathy (IMNM), anti-synthetase syndrome (ASyS), and dermatomyositis (DM)

(1) Meyer et al., Rheumatology. 2015; (2) Pinal-Fernandez et al., Curr Rheumatol Rep. 2018; (3) Schmidt, Journal of Neuromuscular Diseases. 201824

Many Myositis-Specific Autoantibodies Have Been Identified

EULAR/ACR* classification criteria for adult myositis

Classification IMNM, ASyS and DMbased on clinical symptoms

*American College of Rheumatology European Alliance of Associations for Rheumatology

Aggarwal; Lundberg, Ann Rheum Dis. 2017

DMOverlapMyositis

SRP

U1RNP

PM-Scl

Ku

Mi-2

MJ

PL-12

Jo-1

PL-7

Polymyositis

EJ

TIF-1γ

HMGCR

MDA-5

KS

OJ

SAE

IMNM

ASyS Myositis classification is based on myositis-specific autoantibodies (IgG) and clinical symptoms

25

IMNM Autoantibodies Trigger Muscle Damage and Impair Muscle Regeneration

Anti-SRP/-HMGCR autoantibodies bind

muscle fiber

Classical complement activation →

Myolysis (muscle enzymes e.g., CK)

Macrophage recruitment and activationIL-1, IL-6, TNF → atrophy

5 Blocking myotube formation

Allenbach, Nature Reviews Rheumathology. 2020

Necrosis

Complement independent Autoantibodies

1

2

3 4

Complement dependent Complement independent

26

DM and ASyS Autoantibodies Activate Complement and Type 1 Interferon

Autoantibodies

Complement Activation

Interferon Production

Myolysis

Disruption of capillaries Hypoperfusion

Type 1 Interferon• Impaired myotube formation• Impaired angiogenesis: destruction of capillaries and hypoperfusion

Atrophy

21

21

Increased autoantibody production

Dendritic cells produce Type 1 interferon from immune complexes

Necrosis

complement

Complement Activation

1 2

27

Autoantibodies are Central Mediators of Myositis Pathophysiologies

Complement activation of muscle lysis

Complement activation of endothelial cell lysis

Interferon production alpha/beta induce atrophy

Inhibition of myotube formation

Summary of Mode of Action of Autoantibodies

complement

type 1 interferon

myotubeautoantibody

28

Efgartigimod Designed to Clear IgG Autoantibodies Regardless of Target Antigen

Myositis patients can have myositis-specific autoantibodies (MSA+), myositis-associated autoantibodies (MAA+) or autoantibodies against yet unknown targets

IMNM (70% MSA+) ASyS (100% MSA+) DM (75% MSA+)

Defining new myositis biology

anti-SRP

Anti-HMGCR

MAA or Abs against unidentified targets

anti-Jo-1

anti-PL-12

anti-PL-7

other anti-synthetases

anti-Mi-2

anti-NXP-2

anti-MDA5

anti-TIF-1y

anti-SAE

MAA or Abs againstunidentified targets

29

Biology Rationale is at the Core of our Indication Selection

Preclinical EvidencePassive transfer model of IMNM autoantibodies from patient serum induce muscle weakness and loss of grip strength in mice

Clinical EvidenceNo approved targeted therapies for myositis but common immune therapies* show correlation of autoantibodies to disease progression

• Correlation of identity of autoantibodies to muscle damage across myositis subtypes

• Direct link between titer of autoantibody and disease activity

• Rituximab and IVIg evidence demonstrate autoantibodies are foundational drivers of disease

*Plasmapheresis and immunoadsorption (commonly used as correlates for efgartigimod) are not used in the treatment of myositis

30

Autoantibody Levels Correlate to Indicators of Myositis: CK Levels and Muscle Strength

Benveniste et al., Arthritis Rheumatol. 2011; Stone et al., Arthritis and Rheumatism 2007; Allenbach et al, Medicine (Baltimore). 2014; Muro et al., Rheumatology 2012

Patients were treated with standard of care immunosuppressants

• Similarly, anti-HMGCR, -Jo-1 and -Mi-2 titers correlate with CK levels and muscle strength• Anti-MDA5, -Jo-1 and -Mi-2 titers correlate with extramuscular disease activities (e.g. interstitial lung disease, skin disease)

31

ASyS and DM: Anti-Jo-1 and Anti-Mi-2 Patients Respond to Rituximab

Shorter time to improvement in patients positive for anti-Jo-1 and anti-Mi-2 autoantibodies

Anti-Jo-1 and anti-Mi-2 levels decreased after B-cell depletion

Correlation of anti-Jo-1 and anti-Mi-2 titers with disease activity measures

Endpoint based on 6 measures: PhGA, PTGA, HAQ, MMT-8, muscle enzymes, extramuscular disease activity score

Anti-Jo-1 and anti-Mi-2 autoantibodies are predictive biomarkers for response

Aggarwal et al, Arthritis Rheumatol. 2015

32

DM Patients Respond to IVIg

ProDERM study:% of patients with increase of ≥20 points on Total Improvement Score (TIS) at week 16

IVIg Placebo

TIS≥20 78.7% 43.8%

TIS≥40 68.1% 22.9%

Aggarwal et al., Arthritis Rheumatol. 2020

2g/kg IVIg/Placebo

33

IMNM Autoantibodies from Patient Serum Induce Muscle Weakness and Loss of Grip Strength

IgG purified from plasma from anti-SRP and anti-HMGCR IMNM patients causes loss of grip strength and muscle weakness in recipient mice

Necrosis and complement deposition are observed similarly inrecipient mice as in IMNM patients

NECROSIS

COMPLEMENT DEPOSITION

Bergua et al., Ann Rheum Dis. 2018

34

1

2

3

Significant Market Opportunity Across Myositis Subsets

REA

CH

ING

PATIENTS

DEFINING NEW BIOLOGY

IMNM:

4K pts U.S.

ASyS:

8K pts U.S.

DM:

21K pts U.S.

33KEstimated eligible myositis patients in U.S.

Role of autoantibody is best-characterized in IMNM

IMNM anchors market opportunity

Building a Basket Trial Concept

Basket trial approach to include ASyS and DM as well

Reaching more patients with high unmet need

Efgartigimod may allow us to redefine all three myositis subsets as being truly IgG-mediated

35

Adaptive Phase 2/3 Enrichment Design

1000mg efgartigimod SC (+ SOC)

Placebo SC (+ SOC)

Total Duration: 26 weeks

Independent adjudication committee

Stratified for• IMNM• ASyS• DM• Severity of muscle

weakness (MMT)

Eligibility criteria• Minimal muscle

weakness• No malignancies Adaptive enrichment

Interim analysis

Independent DSMB

Subpopulation adjustment Sample size re-estimation

IMNM

ASyS

DM

PrimaryResponse based onTotal Improvement Score (TIS)ACR/EULAR endorsed

Key Secondary• Mean change and duration in TIS• Quality of Life• Individual Core Set Measures TIS

• MMT-8 score• Physician Global

Assessment• Patient Global Assessment• HAQ-Disability Index score• Extramuscular Global

Assessment• Muscle enzyme serum level


Placebo SC (+ SOC)


Placebo SC (+ SOC)

IND filing by end of 2021 pending interaction with DCOA and CID division of FDA

180 patients Proposed Endpoints

Adults

36

Efgartigimod is designed to reduce all IgGsregardless of target antigen and can further elucidate myositis biology

Clinical evidence links IgG levels to disease activity

Conclusions

First basket trial design based on unifying biology

>30,000 IMNM, ASyS and DM patients in the U.S. Diverse panel of IgG autoantibodies emerge as key driver of muscle inflammation

Adaptive enrichment trial enables enrollment of broader patient population

37

Sixth Efgartigimod Indication: Bullous PemphigoidPeter VerheesenResearch Fellow

Bullous Pemphigoid: Most Common Autoimmune Blistering DiseaseSevere, rare, chronic and recurrent autoimmune disorder characterized by fluid-filled blisters, itching and skin redness

BULLOUS PEMPHIGOID IS MEDIATED BY AUTOANTIBODIES

12 per 100,0001

Increasing with aging population

Median age of onset is 81 years

Time to remission

High relapse rate

Side effects from corticosteroids

No approved treatments

Topical/systemic corticosteroids, steroid-sparing agents, rituximab, IVIg

Severe blistering disease

Strong impact on quality of life

High mortality rate2.40 (U.S.)2

PREVALENCE UNMET NEEDTREATMENTBURDEN

Significant market opportunity with ~41K patients in the U.S.

(1) Wertenteil et al., J Am Acad Dermatol. 2019; (2) Tedbirt et al., JAMA Dermatol. 2021; argenx market research

39

Bullous Pemphigoid Autoantibodies are Origin of Blister Formation

Drawn after Schmidt E, Zillikens D. Lancet. 2013; Fang H, Li Q, Wang G. Autoimmun Rev. 2020

• BP180 and BP230: key pathogenic hemidesmosomal antigens driving blistering between epidermis and dermis

• Autoantibody actions:

• Mechanical disruption of keratinocyte adhesion

• IgG autoantibody deposition triggers complement activation

• Recruitment and activation of immune cells (inflammatory cell recruitment, release of proteolytic enzymes)

40

Passive Transfer Model Highlights Toxicity of Bullous Pemphigoid Autoantibodies

Pathogenic autoantibodies induce typical skin lesions in murine passive transfer model of bullous pemphigoid

FcRn-knockout mice show fast elimination of pathogenic autoantibodies and are resistant to disease

Mice injected with BP180 Ab HDIG lowers BP180 Ab levels and improves disease scores

Mice injected with BP180 Ab FcRn -/-: Degradation of BP180 Ab

HDIG: High-dose human IgGLi et al., J Clin Invest. 2005

41

Bullous Pemphigoid Disease Activity Improves with Increasingly Selective IgG Therapies

Selectivity for IgG ResponseTrial

• Clear therapeutic benefit• Stronger response in severe disease• Fast improvement

• 100% complete remission• 70% prednisone dose reduction

Clinical evidence for the role of pathogenic autoantibodies in bullous pemphigoid

• Phase 3 double-blind randomized trial• 56 patients • High dose IVIg (5 days) + oral

corticosteroids

• Case series• 5 patients• PLEX (7–14 cycles) in 4-8 weeks

• Two case series• 27 patients*• Immunoadsorption (most 1 cycle)

• Strong antibody reductions• 68% complete remission • 37% off oral corticosteroids • No need for second cycle in most

patients

IVIg

PLEX

Immunoadsorption(Protein A)

* 4 recalcitrant BP, 3 first line with high disease activity, 20 severe or refractory(1) Kasperkiewicz et al., J Am Acad Dermatol. 2014; (2) Hübner et al., J Dtsch Dermatol Ges. 2018(3) Mazzi, Transfusion and Apheresis Science. 2003; (4) Amagai et al., J. Dermatol. Sci. 2017

42

IgG-Targeted Therapies Drive Fast Remissions

Plasma Exchange (PLEX) 2

Dis

ease

act

ivit

y

Ch

ange

in e

rosi

on

s/b

liste

rs

IVIg1 Protein A Immunoadsorption3

BP

18

0 N

C1

6A

ELIS

A(U

/ml)

1

(1) Amagai et al., J. Dermatol. Sci. 2017(2) Mazzi, Transfusion and Apheresis Science. 2013(3) Kasperkiewicz et al., J Am Acad Dermatol. 2014

43

BULLOUS PEMPHIGOID

Pemphigus Serves as Proof of Concept for Autoimmune Blistering Diseases

PEMPHIGUS

Fast onset of action

Significant responses

Favorable tolerability seen in data to date

Autoantibodies initiate disease

Pathophysiology of blister formation more heterogeneous

Larger yet more elderly, fragile population

• 90% disease control after median time of 17 days

• 64% complete clinical remission after median 92 days• Corticosteroid sparing potential by using lower initial

doses of corticosteroids and rapid tapering

Proof of Concept in Initial Indication… …Before Expansion into Adjacent Indications

Important to confirm efgartigimod profile in pemphigus before expanding into other skin indications

S K I N B L I S T E R I N G D I S E A S E S – A U T O A N T I B O D Y D R I V E N

44

Registrational Study of Bullous Pemphigoid to Start in 2021


Bullous Pemphigoid

Moderate-to-severe disease (BPDAI activity score ≥ 20)

Newly diagnosed and relapsing within 1 year of diagnosis

Proposed primary endpoint• proportion of participants in

complete or partial remission while off OCS

Secondary endpoints• cumulative dose of OCS• time to complete remission on

minimal OCS• proportion of participants with CDA

and remain free of relapse• quality of life

Followed by Open Label Extension study

Study Population Endpoints

Randomization (1:1)

Efgartigimod weekly SC

Placebo weekly SC

Concomitant Oral Corticosteroids (OCS)

OCS starting dose 0.5 mg/kg/day with ability to adjust

Active tapering to start from sustained control of disease activity (CDA)

45

IgG autoantibodies against BP180/BP230are hallmark of bullous pemphigoid

Conclusions

~41K bullous pemphigoid patients in U.S. Preclinical and clinical evidence links IgG autoantibody level to disease activity

Robust Phase 2 PoC data for efgartigimod in pemphiguslead to bullous pemphigoid Phase 3 trial design

Second registrational trial in skin franchise to start in parallel to ongoing pemphigus trial

46

KOL Panel: Myositis and Bullous Pemphigoid

Russell P. Hall III, MDJ. Lamar Callaway Professor, Department of Dermatology, Duke University Medical Center

Rohit Aggarwal, MD, MSRheumatology, Professor of Medicine, Medical Director, Arthritis and Autoimmunity Center, Co-Director UPMC Myositis Center, Division of Rheumatology and Clinical Immunology, Department of Medicine, University of Pittsburgh

48

ARGX-117 Phase 1 Data | New Biology Insights for Multifocal Motor NeuropathyOlivier Van de Steen, Medical Director

Inge Van de Walle, Principal Scientist

Inflammation

C5 convertase

C3 convertase

IgG IgM Mannose sugar Foreign surface

C3a-R

C5a-R

Sublytic MAC

ARGX-117 is First in Class Targeting C2(Auto)antibodies

Classical Lectin Alternative

Clearance by macrophages

Membrane damage

C3b C3 C3a

C5 C5a

C1qrs

C4

C2

C5b-C9MAC

C3

CFB CFD

MBL

MASPs

Microorganisms

50

C2 is Ideal Point of Intervention within Complement Cascade

C5 convertase

C3 convertase

Inflammation


C3a-R

C5a-R

Sublytic MAC

Target upstream of C5 to shut down all effector functions

Intact alternative pathway to reduce

infection risk

Crossroad of classical & lectin pathwaysManageable C2 levels in circulation

Benign C2-deficiency phenotype

(Auto)antibodies Microorganisms



Membrane damage

C3b C3 C3a

C5 C5a

C1qrs

C4

C2

C5b-C9MAC

C3

CFB CFD

MBL

MASPs

2

3

1

51

C5 convertase

C3 convertase

Inflammation


C3a-R

C5a-R

Sublytic MAC



infection risk

Crossroad classical & lectin pathwayManageable C2 levels in circulation





Membrane damage

C3b C3 C3a

C5 C5a

C1qrs

C4

C2

C5b-C9MAC

C3

CFB CFD

MBL

MASPs

2

3

1


C2 is Ideal Point of Intervention within Complement Cascade(Auto)antibodies Microorganisms


C1qrs

C4

C2

C3

CFB CFD

MBL

MASPs


1

52

C5 convertase

C3 convertase

Inflammation


C3a-R

C5a-R

Sublytic MAC



infection risk






Membrane damage

C3b C3 C3a

C5 C5a

C1qrs

C4

C2

C5b-C9MAC

C3

CFB CFD

MBL

MASPs

2

3

1

IgG IgM Mannose sugar


Classical Lectin

C1qrs

C4

C2

MBL

MASPs


infection risk

2

53

C5 convertase

C3 convertase

Inflammation


C3a-R

C5a-R

Sublytic MAC



infection risk






Membrane damage

C3b C3 C3a

C5 C5a

C1qrs

C4

C2

C5b-C9MAC

C3

CFB CFD

MBL

MASPs

2

3

1


C4

C2

Crossroad of classical & lectin pathwaysManageable C2 levels in circulation


3

54

Features of ARGX-117

Optimal recycling

pH and Ca2+

switch

No effector function

Sweeping Antibody

ARGX-117 Blocks and Actively Removes C2 from Circulation

Bind & block C2

Degradation of C2

1

3

Recycling of ARGX-1174

Uptake & drop off C22

55

Ongoing Robust Phase 1 First-in-Human Study

Single Ascending Dose (SAD): IV and SC

0.1 mg/kgIV

N=8

0.5 mg/kgIV

N=8

2.5 mg/kgIV

N=8

10 mg/kgIV

N=7

30 mg/kgIV

N=7

60 mg/kgIV

N=8

60 mg/kgSC

N=8

80 mg/kgIV

N=8

15 mg/kgSC

N=8

10-10-10-10*mg/kg

IVN=8

60-10-10# mg/kg

IVN=8

10-50-20# mg/kg

IVN=8

15-15-15-15* mg/kg SC

N=8

Multiple Ascending Dose (MAD): IV and SC

IMP = Investigational Medicinal Product*IMP administered on Days 1, 8, 15 & 22#IMP administered on Days 1, 8 & 22

• Broad dose range investigated with both IV and SC formulations (up to 80 mg/kg and 60 mg/kg respectively)• 102 subjects dosed (70 in SAD, 32 in MAD) yielding comprehensive clinical, PK/PD and biomarker dataset• 75 subjects exposed to ARGX-117

56

Phase 1 Safety Results Support Proof of Concept Studies in Patients

Treatment-Emergent Adverse Events (TEAE)

0.1mg/kg

0.5mg/kg

2.5mg/kg

10mg/kg

30mg/kg

60mg/kg

60mg/kg

SC

80mg/kg

15mg/kg

SC

10-10-10-10mg/kg

60-10-10mg/kg

10-50-20mg/kg

15-15-15-15mg/kg

SC

N (%)

Any 6 (75.0) 5 (62.5) 5 (62.5) 5 (71.4) 7 (100) 5 (62.5) 5 (62.5) 6 (75.0) 6 (75.0) 6 (75.0) 8 (100) 8 (100) 8 (100)

Grade 2 1 (12.5) 1 (12.5) 1 (12.5) - - 1 (12.5) 2 (25.0) - - - - - -

Grade 3 or higher

- - - - - - - - - - - - -

Serious - - 1 (12.5) - - - - - - - - - -

TEAE = treatment emergent adverse eventn = number of subjects that experienced at least one TEAE% = number of subjects (n) as percentageData Cut-off for Interim Analysis: May 20th 2021

• TEAEs primarily Grade 1 and not dose-related• Serious TEAE determined to be unrelated to drug• No increased risk of infection

Single and multiple administrations of ARGX-117 or placebo show favorable safety and tolerability profile to date*

*Safety data still blinded in Phase 1 study

57

Pharmacokinetics

• Estimated half-life ~ 65-70 days• Dose proportional increase of Cmax

• Sustained reduction in free C2 levels by 95% for > 100 days as of 30 mg/kg doseConclusions

Free C2 levels

Days

99% reduction

95% reduction

ARGX-117 SAD: Long Half-life and Sustained PD Profile

Days

58

• Induction dose followed by maintenance dosing concept established• Resulting robust PK/PD model informing dosing strategy for Phase 2 studies

DaysDays

99%reduction

95%reduction

ARGX-117 MAD: Consistent Activity

Pharmacokinetics Free C2 levels

Conclusions

59

Model assumes full complement blockage as of free C2 levels < 0.2 µg/mL or >99% reduction of free C2 levels

Model Predicts Potential for Infrequent Dosing

Free C2 levels

60

Phase 1 Data Support Path Forward and Potential for Individualized Dosing Schedule in Patients

Favorable safety & tolerability profile supports advancing to Phase 2 patient trials

Consistent PK/PD profile across IV and SC dosing that may enable infrequent dosing

Phase 2 trial in multifocal motor neuropathy (MMN) to start by end of year

61

Multifocal Motor Neuropathy:A Serious, Debilitating Autoimmune Disease

Need for new therapies that slow progression of disease and reduce reliance on IVIg

~13,000 patients in the U.S. –increasing

Often underdiagnosed

Predominantly men

Median age 40 years

Steroids ineffective

First line and only approved therapy is frequent, high doses of IVIg over 2-5 days

Often misdiagnosed as ALS

Takes ~1.5 years for correct diagnosis

Nerve conduction blocks

Anti-GM1 IgM antibody presence

Slowly progressive muscle weakness due to motor neuron degeneration

Mainly affects hands and forearms -patients become dependent

PREVALENCE UNMET NEEDDIAGNOSISHALLMARK

>$0.5B IVIg sales and growing

Persson et al., Br J Dermatol. 2021; Tedbirt et al., JAMA Dermatol. 2021; Wertenteil et al., J Am Acad Dermatol. 2019; argenx market research

62

Anti-GM1 Antibodies Activate Classical Complement Pathway

Muscle weakness

1 2

3 4

IgM autoantibodies bind to GM1 located on motor neurons and Schwann cells

IgM autoantibodies are potent activators of the complement cascade

IgM titer is correlated with classical pathway complement deposition

Complement activity correlates with disease severity

SoC IVIg reduces C3b deposition

Vlam et al, Neurol Neuroimmunol Neuroinflamm. 2015Yuki et al, J Peripheral Nervous System. 2011 IgM autoantibodies cannot be addressed by efgartigimod

63

ARGX-117 Inhibits Complement Deposition on Motor Neurons and Schwann Cells

C3

DEP

OSI

TIO

NC2 depleted serum + 100% C2

C3

DEP

OSI

TIO

NIsotype control IVIg C2 depleted serum ARGX-117

Complement active serum

Serum MMN Patient

Motor neurons

Schwann cells

64


ARGX-117 Blocks C3 Deposition in Dose-Dependent Manner

Isotype control

C2 depleted serum

C3

DEP

OSI

TIO

NC

3 D

EPO

SITI

ON

ARGX-117 (200 µg/mL – 3,1 µg/mL)

Reconstitution with hC2 (1,97 µg/mL - 30 µg/mL)

Motor neurons

Schwann cells


65

ARGX-117 Protects Axon Integrity While Blocking C3 Deposition in ex vivo ModelARGX-117 prevents loss of neurofilament staining at the nerve terminal and thereby preserves the integrity of the axon by blocking C3 deposition and downstream complement activation

Isotype control ARGX-117

C3

de

po

siti

on

Ne

uro

fila

men

t

GalNAcT-/- (neuronal mice) - Yao et al., Journal of Neuroscience. 2014; Mouse model - McGonigal et al., Acta Neuropathologica Communications. 2016

66

Phase 2 Multifocal Motor Neuropathy Trial Design


Trial to enroll approximately 45 MMN patients• Probable or definite

MMN (per EFNS/PNS 2010)

• Independent adjudication committee

• Stable IVIg regimen• IVIg treatment

dependent

Safety and tolerability

Time to IVIg re-treatment

Measures of peripheral muscle strength: grip strength, mMRC sum score, 9-HPT, MMN-RODS

Patient-reported outcomes

PK, PD, biomarkers

Patient Population Key Outcome Measures

Trial on track to start by end of 2021

ARGX-117 Dose Regimen 1 (N=15)

ARGX-117 Dose Regimen 2 (N=15)

Placebo (N=15)

ARGX-117Open-label Extension

Ran

do

miz

atio

n(1

:1:1

)

IVIgMonitoring

Period

4-10 weeks

67

ARGX-117: Pipeline-in-a-Product Opportunityfitting our franchises

MMNNeuro

Heme

Skin

Kidney

Indications

TherapeuticFranchises

Classical Pathway

Lectin Pathway

GBS

IgAN

MN

CAD

IRI

MG

LN

ALS

ITP

C4GN

MGUS anti-MAG

BP

HS

68

Q&A

Tim Van HauwermeirenChief Executive Officer and Co-Founder, argenx

Hans de Haard, PhDChief Scientific Officer and Co-Founder, argenx

Wim Parys, MDChief Medical Officer, argenx

Keith WoodsChief Operating Officer, argenx

Karl GubitzChief Financial Officer, argenx

Bas van der Woning, PhDResearch Fellow, argenx

Peter Verheesen, PhDResearch Fellow, argenx

Rohit Aggarwal, MD, MSUniversity of Pittsburgh

Russell P. Hall III, MDDuke University

Olivier Van de Steen, MDMedical Director, argenx

Inge Van de Walle, PhDPrincipal Scientist, argenx

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