argenx Announces U.S. Food and Drug Administration (FDA) Approval of VYVGART Ô (efgartigimod alfa-fcab) in Generalized Myasthenia Gravis VYVGART is the first-and-only FDA-approved neonatal Fc receptor blocker 68% o

Announces U.S. Food and Drug Administration (FDA) Approval of VYVGART (efgartigimod

alfa-fcab) in Generalized Myasthenia Gravis

is the first-and-only FDA-approved neonatal Fc receptor blocker

of anti-acetylcholine receptor (AChR) antibody positive gMG patients treated with VYVGART were responders (n=44/65) on the Myasthenia

Gravis - Activities of Daily Living (MG-ADL) scale compared with 30% of patients treated with placebo (n=19/64) (p<0.0001) during the

first treatment cycle in the Phase 3 ADAPT trial

has reached agreement in principle with various national and regional payers to structure value-based agreements

to host investor conference call today at 5:30pm ET

Regulated Information/Inside Information

the Netherlands-Dec. 17, 2021-argenx SE (Euronext & Nasdaq: ARGX), a global immunology company committed

to improving the lives of people suffering from severe autoimmune diseases and cancer, today announced that the U.S. Food and Drug Administration

(FDA) has approved VYVGART (efgartigimod

alfa-fcab) for the treatment of generalized myasthenia gravis (gMG) in adult patients who are anti-acetylcholine receptor (AChR) antibody

positive. These patients represent approximately 85% of the total gMG population1. With this regulatory milestone, VYVGART

is the first-and-only FDA-approved neonatal Fc receptor (FcRn) blocker.

This press release features multimedia. View the

"Today is the start of a new era for argenx

and the gMG community as we honor our commitment to bring forward an innovative treatment option for people living with this debilitating

disease. The approval of VYVGART represents many achievements: our first approved product; the first-and-only FDA-approved neonatal Fc

receptor blocker; and the first approved therapy designed to reduce pathogenic IgGs, an underlying driver of gMG," said Tim Van

Hauwermeiren, Chief Executive Officer of argenx. "Importantly, we want to thank the patients, supportive caregivers, investigators

and study teams who participated in the ADAPT trial, as well as our partners and dedicated employees for their hard work and collaboration

- all of whom made this milestone possible.

"Our highly motivated commercial team is

activated and ready to deliver VYVGART to patients. We believe the field of autoimmunity is on the precipice of an evolution, and we hope

that this will be the first of many VYVGART launches, allowing us to help improve the lives of patients around the world," continued

Mr. Van Hauwermeiren.

Generalized myasthenia gravis is a rare and chronic

neuromuscular disease characterized by debilitating and potentially life-threatening muscle weakness. VYVGART is a human IgG1 antibody

fragment that binds to FcRn, resulting in the reduction of circulating immunoglobulin G (IgG) antibodies. The action of AChR autoantibodies

at the neuromuscular junction is a key driver of gMG2.

"The gMG community has long-awaited the

FDA approval of VYVGART, especially for those patients who struggle with basic personal tasks such as speaking, chewing and swallowing

food, brushing teeth and hair, and in some severe cases, breathing," commented Samantha Masterson, President and Chief Executive

Officer of the Myasthenia Gravis Foundation of America. "We thank argenx for its continued commitment to the gMG patient community,

which led them to deliver this much-needed new treatment option with the potential to change the lives of many gMG patients."

Proven clinical efficacy and safety profile

"People living with gMG have been in need

of new treatment options that are targeted to the underlying pathogenesis of the disease and supported by clinical data," said 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. "Today's approval represents

an important new advance for gMG patients and families affected by this debilitating disease. This therapy has the potential to reduce

the disease burden of gMG and transform the way we treat this disease."

The approval of VYVGART is based on results from

the global Phase 3 ADAPT trial, which were published in the July 2021 issue of The Lancet Neurology.

The ADAPT trial met its primary endpoint, demonstrating that significantly more anti-AChR antibody positive gMG patients were responders

on the MG-ADL scale following treatment with VYVGART compared with placebo (68% vs. 30%; p<0.0001). Responders were defined as having

at least a two-point reduction on the MG-ADL scale sustained for four or more consecutive weeks during the first treatment cycle.

There were additionally significantly more responders

on the Quantitative Myasthenia Gravis (QMG) scale following treatment with VYVGART compared with placebo (63% vs. 14%; p<0.0001). Responders

were defined as having at least a three-point reduction on the QMG scale sustained for four or more consecutive weeks during the first

VYVGART had a demonstrated safety profile

in the ADAPT clinical trial. The most common adverse events in ADAPT were respiratory tract infection (33% vs 29% placebo), headache (32%

vs 29% placebo), and urinary tract infection (10% vs. 5% placebo).

Access and My VYVGART Path

argenx is committed to supporting affordable access

to VYVGART. As part of this commitment, argenx is launching My VYVGART Path, a program designed to connect patients and clinicians

to personalized support throughout the treatment journey. Program resources include disease and product education, access support and

benefits verification, and financial assistance programs for eligible patients. Patients and healthcare providers can visit VYVGART.com

for more information.

Adults living with gMG each experience the course

of the disease differently, contributing to variability of disease severity and response to therapies. argenx prioritized early and active

engagement with leading payers to address questions around broader budget predictability. The Company has reached agreements in principle

with several national and regional commercial payers to structure a value-based agreement. The agreements are meant to provide predictability

of cost for payers and appropriate access for patients.

"Generalized myasthenia gravis imposes a

significant lifestyle and treatment burden on patients, families, and the overall healthcare system. This autoimmune disease affects each

patient differently which can create variability in dosing and the resulting cost per patient," said Steve Miller, M.D., Executive

Vice President and Chief Clinical Officer at Cigna Corp. "The approval of VYVGART promises to address a treatment gap for patients

suffering from this disease. argenx has put forth an innovative, value-based approach to contracting that will help payers with cost predictability

as they face the challenge of ensuring real-world dosing remains affordable. This was a direct result of early engagement between argenx

and Evernorth leading up to approval. Cigna looks forward to continued collaboration with argenx to enable appropriate access to the gMG

patients who will benefit from VYVGART."

Marketing Authorization Applications for efgartigimod

for the treatment of gMG are currently under review with Japan's Pharmaceuticals and Medical Devices Agency (PMDA) and the European

Medicines Agency (EMA), with anticipated decisions from each agency in the first quarter and second half of 2022, respectively.

argenx has an exclusive partnership agreement

with Zai Lab for the development and commercialization of efgartigimod in Greater China. Zai Lab is on track to file for approval in Greater

China by mid-2022. Under the terms of the strategic agreement with Zai Lab, argenx will receive a $25 million milestone payment with this

U.S. approval of VYVGART. In addition, argenx has an exclusive partnership with Medison for the commercialization of efgartigimod in gMG

in Israel. Medison is on track to file for approval in Israel in the second quarter of 2022.

Conference Call and Webcast

A webcast of the live call may be accessed on

the Investors section of the argenx website at argenx.com/investors. A replay of the webcast will be available on the argenx website

for approximately one year following the call.

Please dial in 15 minutes prior to the live call.

See Important Safety Information and full Prescribing

Information below for additional information.

What is VYVGARTTM (efgartigimod

VYVGART is a prescription medicine used to treat

a condition called generalized myasthenia gravis, which causes muscles to tire and weaken easily throughout the body, in adults who are

positive for antibodies directed toward a protein called acetylcholine receptor (anti-AChR antibody positive).

What is the most important information I should

VYVGART may cause serious side effects, including:

Before taking VYVGART, tell your health care provider

about all of your medical conditions, including if you:

Tell your health care provider about all the medicines

you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

What are the common side effects of VYVGART?