argenx Presents Additional Efgartigimod Data from Global Phase 3 ADAPT Trial at the Myasthenia Gravis Foundation of America 2020 Scientific Session - New data consistent with positive topline results showing rapid and cl

argenx Presents Additional Efgartigimod

Data from Global Phase 3 ADAPT Trial

at the Myasthenia Gravis Foundation of America 2020 Scientific Session

- New data consistent with positive topline results showing rapid and clinically meaningful responses to efgartigimod and safety profile comparable to placebo

- Biologics License Application on track to be submitted to U.S. Food and Drug Administration by end of 2020

Breda, the Netherlands / Ghent, Belgium

- argenx (Euronext & Nasdaq: ARGX), a global immunology

company committed to improving the lives of people suffering from severe autoimmune diseases and cancer, today announced the presentation

of new data from the pivotal Phase 3 ADAPT trial evaluating efgartigimod for the treatment of patients with generalized myasthenia

gravis (gMG). The presentation took place on Saturday, October 3, 2020 at the Myasthenia Gravis Foundation of America (MGFA)

2020 Virtual Scientific Session. argenx previously reported positive topline results from ADAPT in May 2020.

"Myasthenia gravis can be a very

debilitating and potentially life-threatening chronic disease in patients leading to impairments that affect a patient's

ability to complete normal daily activities, including walking, swallowing, chewing food, talking or breathing easily. Efgartigimod

demonstrated in ADAPT that it is well-tolerated and that patients can experience clinically meaningful improvements in key measures

of function and strength following treatment, including, in some, the achievement of minimal symptom expression. These exciting

results suggest that efgartigimod as a new potential therapy for gMG patients could have a real impact on some of the daily limitations

that patients face," commented James F. Howard Jr., M.D., Professor of Neurology (Neuromuscular Disease), Medicine and Allied

Health, Department of Neurology, The University of North Carolina at Chapel Hill School of Medicine and principal investigator

for the ADAPT trial.

Highlights of New Data Presented at

MGFA 2020 Virtual Scientific Session

Magnitude of response:

Substantial proportion of efgartigimod-treated acetylcholine receptor-antibody positive (AChR-Ab+) patients showed benefit at increasing

thresholds on the Myasthenia Gravis Activities of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) scores compared

to placebo patients at week four (one week after first treatment cycle).

of response: Similar proportion of efgartigimod-treated AChR-Ab+ patients were MG-ADL responders in the first (67.7%

efgartigimod versus 29.7% placebo) and second (70.6% efgartigimod versus 25.6% placebo) treatment cycles (p<0.0001 for both

benefit in seronegative patients: Inclusion of QMG score in responder analysis showed further evidence of activity in

patients where AChR antibodies were not detected (AChR-Ab-)

parameters: Total IgG and pathogenic autoantibody levels were reduced in efgartigimod-treated AChR-Ab+ patients throughout

observation period, supporting proposed mechanism of action

Key Topline Data Previously Reported

data from ADAPT were reported in May 2020. The trial met its primary endpoint showing 67.7% of efgartigimod-treated

AChR-Ab+ gMG patients were responders on the MG-ADL score compared to 29.7% of placebo patients (p<0.0001). Responders were

defined by having at least a 2-point change on the MG-ADL for at least four consecutive weeks. Efgartigimod was demonstrated to

be well-tolerated with a safety profile that was comparable to placebo.

"These new data on the magnitude

and repeatability of response continue to support the potential of efgartigimod as a meaningful treatment for gMG patients. ADAPT

was also a broad trial which included patients with acetylcholine receptor antibodies present and those without. We were pleased

to show in this presentation proof of activity in the antibody-negative patients who are often left out of clinical trials,"

commented Wim Parys, M.D., Chief Medical Officer of argenx. "It is particularly gratifying to present these favorable new

data at the MGFA Virtual Scientific Session, a scientific meeting solely focused on addressing unmet needs for people living with

gMG. We look forward to submitting our Biologics License Application for efgartigimod to the U.S. Food and Drug Administration

before the end of the year with the goal to have efgartigimod available to patients and physicians in 2021."

3 ADAPT trial was a randomized, double-blind, placebo-controlled, multi-center, global trial evaluating the safety and efficacy

of efgartigimod in patients with gMG. A total of 167 adult patients with gMG in North America, Europe and Japan enrolled in the

trial and were treated. Patients were eligible to enroll in ADAPT regardless of antibody status, including patients with AChR antibodies

(AChR-Ab+) and patients where AChR antibodies were not detected. Patients were randomized in a 1:1 ratio to receive efgartigimod

or placebo for a total of 26 weeks. ADAPT was designed to enable an individualized treatment approach with an initial treatment

cycle followed by a variable number of subsequent treatment cycles. The primary endpoint was the number of AChR-Ab+ patients who

achieved a response on the MG-ADL score defined by at least a two-point improvement for four or more consecutive weeks.

Efgartigimod is an investigational antibody

fragment designed to reduce disease-causing immunoglobulin G (IgG) antibodies and block the IgG recycling process. Efgartigimod

binds to the neonatal Fc receptor (FcRn), which is widely expressed throughout the body and plays a central role in rescuing IgG

antibodies from degradation. Blocking FcRn reduces IgG antibody levels representing a logical potential therapeutic approach for

several autoimmune diseases known to be driven by disease-causing IgG antibodies, including: myasthenia gravis (MG), a chronic

disease that causes muscle weakness; pemphigus vulgaris (PV), a chronic disease characterized by severe blistering of the skin;

immune thrombocytopenia (ITP), a chronic bruising and bleeding disease; and chronic inflammatory demyelinating polyneuropathy (CIDP),

a neurological disease leading to impaired motor function.

About Myasthenia Gravis (MG)

MG is a rare and chronic autoimmune disease

where IgG antibodies disrupt communication between nerves and muscles, causing debilitating and potentially life-threatening muscle

weakness. More than 85% of people with MG progress to generalized MG (gMG) within 18 months, where muscles throughout the body

may be affected, resulting in extreme fatigue and difficulties with facial expression, speech, swallowing, and mobility. In more

life-threatening cases, MG can affect the muscles responsible for breathing. Patients with confirmed AChR antibodies account for

80-90% of the total gMG population. There are approximately 65,000 people in the United States and 20,000 people in Japan living

argenx is a global immunology

company committed to improving the lives of people suffering from severe autoimmune diseases and cancer. Partnering with leading

academic researchers through its Immunology Innovation Program (IIP), argenx aims to translate immunology breakthroughs into a

world-class portfolio of novel antibody-based medicines. argenx is evaluating efgartigimod in multiple serious autoimmune diseases,

and cusatuzumab in hematological cancers in collaboration with Janssen. argenx is also advancing several earlier stage experimental

medicines within its therapeutic franchises. argenx has offices in Belgium, the United States, and Japan. For more information,

Forward-looking Statements

The contents of this announcement include statements that

are, or may be deemed to be, "forward-looking statements." These forward-looking statements can be identified by the

use of forward-looking terminology, including the terms "believes," "estimates," "anticipates,"

"expects," "intends," "may," "will" or "should" and include statements

argenx makes concerning the timing of its BLA submission to the FDA and the availability of efgartigimod to patients and physicians

and the therapeutic potential of its product candidates. By their nature, forward-looking statements involve risks and uncertainties

and readers are cautioned that any such forward-looking statements are not guarantees of future performance. argenx's actual

results may differ materially from those predicted by the forward-looking statements as a result of various important factors,

including argenx's expectations regarding its the inherent uncertainties associated with competitive developments, preclinical

and clinical trial and product development activities and regulatory approval requirements; argenx's reliance on collaborations

with third parties; estimating the commercial potential of argenx's product candidates; argenx's ability to obtain

and maintain protection of intellectual property for its technologies and drugs; argenx's limited operating history; and

argenx's ability to obtain additional funding for operations and to complete the development and commercialization of its

product candidates. A further list and description of these risks, uncertainties and other risks can be found in argenx's

U.S. Securities and Exchange Commission (SEC) filings and reports, 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. Given these uncertainties, the reader

is advised not to place any undue reliance on such forward-looking statements. These forward-looking statements speak only as of

the date of publication of this document. argenx undertakes no obligation to publicly update or revise the information in this

press release, including any forward-looking statements, except as may be required by law.

For further information, please contact:

Beth DelGiacco, Vice President, Investor Relations (US)

Joke Comijn, Director Corporate Communications & Investor