argenx Data Highlight Evidence that VYVGART and VYVGART Hytrulo Drive Transformative Outcomes for Patients with Debilitating Autoimmune Disease ADHERE data show VYVGART Hytrulo has potential to be first advancement for C

argenx Data Highlight

Evidence that VYVGART and VYVGART Hytrulo Drive Transformative Outcomes for Patients with Debilitating Autoimmune Disease

VYVGART Hytrulo has potential to be first advancement for CIDP patients in 30 years

demonstrate gMG patients able to significantly reduce steroid use over first six months of initiating VYVGART

April 16, 2024 - 7:00am CET

Netherlands - argenx SE (Euronext & Nasdaq: ARGX), a global immunology company committed to improving the lives

of people suffering from severe autoimmune diseases, today announced that data from its Phase 3 ADHERE trial evaluating VYVGART Hytrulo

(efgartigimod alfa and hyaluronidase-qvfc) in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) were presented for

the first time to the medical community during the Clinical Trials Plenary Session at the American Academy of Neurology (AAN) Annual

Meeting in Denver, CO.

argenx also highlighted clinical trial and real-world

data across seven posters and presentations that continue to reinforce VYVGART and VYVGART Hytrulo as a transformative treatment option

"Our innovative approach to autoimmunity

research is changing expectations for the global immunology community," said Luc Truyen, M.D., Ph.D., Chief Medical Officer, argenx.

"The gMG and CIDP data presented at AAN reinforce that our pioneering approach to transforming autoimmunity is redefining what

is possible for patients and their communities."

"Patients with CIDP face a number of diagnostic

and treatment challenges" said Jeffrey Allen, M.D., Professor, Department of Neurology, University of Minnesota and Principal Investigator

in the ADHERE trial. "The results of the ADHERE trial show that VYVGART Hytrulo reduces the risk of clinical deterioration in patients

with CIDP while minimizing side effects and reducing the treatment burden. These findings enhance our understanding of the role that

IgG autoantibodies are likely to play in the disease, and open the door to new safe, effective and well-tolerated treatments that eliminate

ADHERE Plenary Session (PL5) Highlights Rapid,

Deep and Clinically Meaningful, and Durable Functional Improvements in CIDP

In the ADHERE study, a majority of patients treated

with VYVGART Hytrulo, regardless of prior treatment, demonstrated evidence of rapid clinical improvement, and a reduced risk of relapse

compared to those treated with placebo. As previously reported, ADHERE met its primary endpoint (p=0.000039) demonstrating a 61% reduction

(HR: 0.39 95% CI: 0.25; 0.61) in the risk of relapse versus placebo. VYVGART Hytrulo was well-tolerated, and the observed safety and

tolerability profile was consistent with previous clinical trials.

AAN presentations highlight rapid, deep, and

sustained improvements in gMG with ability to reduce steroid burden

Clinical trial data and real-world evidence presented

during AAN continue to highlight the differentiated efficacy and safety profile of VYVGART and VYVGART Hytrulo, driving rapid, deep,

and sustained improvement across disease scales and with different dosing schedules, including the ability for patients to achieve minimal

symptom expression (MSE).

Side effects from long-term steroid use continue

to be a significant burden associated with autoimmune disease, reinforcing the importance of the favorable safety profile of VYVGART.

New data presented in an oral presentation (Scientific Platform Session 38) during AAN characterize how VVYGART treatment can significantly

reduce concomitant steroid use.

About ADHERE Trial Design

The ADHERE trial was a multicenter, randomized,

double-blind, placebo-controlled trial evaluating VYVGART Hytrulo (efgartigimod alfa and hyaluronidase-qvfc) for the treatment of

chronic inflammatory demyelinating polyneuropathy (CIDP). ADHERE enrolled 322 adult patients with CIDP who were treatment na ve

(not on active treatment within the past six months or newly diagnosed) or being treated with immunoglobulin therapy or corticosteroids.

The trial consisted of an open-label Stage A followed by a randomized, placebo-controlled Stage B. In order to be eligible for the trial,

the diagnosis of CIDP was confirmed by an independent panel of experts. Patients entered a run-in stage, where any ongoing CIDP treatment

was stopped and in order to be eligible for Stage A had to demonstrate active disease, with clinically meaningful worsening on at least

one CIDP clinical assessment tool, including INCAT, I-RODS, or mean grip strength. Treatment na ve patients were able to skip

the run-in period with proof of recent worsening. To advance to Stage B, patients needed to demonstrate evidence of clinical improvement

(ECI) with VYVGART Hytrulo. ECI was achieved through improvement of the INCAT score, or improvement on I-RODS or mean grip strength if

those scales had demonstrated worsening during the run-in period. In Stage B, patients were randomized to either VYVGART Hytrulo or placebo

for up to 48 weeks. The primary endpoint was measured once 88 total relapses or events were achieved in Stage B and was based on the

hazard ratio for the time to first adjusted INCAT deterioration (i.e. relapse). After Stage B, all patients had the option to roll-over

to an open-label extension study to receive VYVGART Hytrulo.

See Important Safety Information below, full

United States Prescribing Information for VYVGART and full Prescribing Information for VYVGART Hytrulo for additional information.

What is VYVGART (efgartigimod

alfa-fcab) for intravenous (IV) infusion and what is VYVGART HYTRULO (efgartigimod alfa and hyaluronidase-qvfc)

for subcutaneous injection?

VYVGART and VYVGART HYTRULO are both prescription

medicines, each 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).

Do not use VYVGART if you have a serious allergy

to efgartigimod alfa or any of the other ingredients in VYVGART. Do not use VYVGART HYTRULO if you have a serious allergy to efgartigimod

alfa, hyaluronidase, or any of the other ingredients in VYVGART HYTRULO. VYVGART and VYVGART HYTRULO can cause serious allergic reactions

and a decrease in blood pressure leading to fainting.

VYVGART and VYVGART HYTRULO may cause serious

side effects, including:

VYVGART and VYVGART HYTRULO may increase the

risk of infection. The most common infections for efgartigimod alfa-fcab-treated patients were urinary tract and respiratory tract infections.

Signs or symptoms of an infection may include fever, chills, frequent and/or painful urination, cough, pain and blockage of nasal passages/sinus,

wheezing, shortness of breath, fatigue, sore throat, excess phlegm, nasal discharge, back pain, and/or chest pain.

Allergic Reactions (hypersensitivity reactions)

VYVGART and VYVGART HYTRULO can cause allergic

reactions such as rashes, swelling under the skin, and shortness of breath. Hives were also observed in patients treated with VYVGART

HYTRULO. Serious allergic reactions, such as trouble breathing and decrease in blood pressure leading to fainting have been reported

with efgartigimod alfa-fcab.

Infusion-Related Reactions

VYVGART and VYVGART HYTRULO can cause infusion-related

reactions. The most frequent symptoms and signs reported with efgartigimod alfa-fcab were high blood pressure, chills, shivering, and

chest, abdominal, and back pain.

Tell your doctor if you have signs or symptoms

of an infection, allergic reaction, or infusion-related reaction. These can happen while you are receiving your VYVGART or VYVGART HYTRULO

treatment or afterward. Your doctor may need to pause or stop your treatment. Contact your doctor immediately if you have signs or symptoms

of a serious allergic reaction.

Before taking VYVGART or VYVGART HYTRULO,

tell your doctor if you:

What are the common side effects of VYVGART

and VYVGART HYTRULO?

The most common side effects in efgartigimod-alfa-fcab-treated

patients were respiratory tract infection, headache, and urinary tract infection. Additional common side effects with VYVGART HYTRULO

are injection site reactions, including rash, redness of the skin, itching sensation, bruising, pain, and hives.

These are not all the possible side effects of

VYVGART and VYVGART HYTRULO. Call your doctor for medical advice about side effects. You may report side effects to the US Food and Drug

Administration at 1-800-FDA-1088.

see the full Prescribing Information for VYVGART and the full Prescribing Information for VYVGART HYTRULO.

Generalized Myasthenia Gravis

myasthenia gravis (gMG) is a rare and chronic autoimmune disease where IgG autoantibodies disrupt communication between nerves and muscles,