argenx Announces FDA Approval of VYVGART Hytrulo for Chronic Inflammatory Demyelinating Polyneuropathy VYVGART Hytrulo is first and only neonatal Fc receptor (FcRn) blocker approved to treat chronic inflammatory demyelin

Announces FDA Approval of VYVGART Hytrulo for Chronic Inflammatory Demyelinating Polyneuropathy

Hytrulo is first and only neonatal Fc receptor (FcRn) blocker approved to treat chronic

inflammatory demyelinating polyneuropathy (CIDP)

novel, precision mechanism of action in more than 30 years for patients with CIDP

approved indication for VYVGART and VYVGART Hytrulo franchise

to host conference call on June 21, 2024 at 11:00pm CET (5:00pm ET)

June 21, 2024, 4:40pm ET

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 the U.S. Food and Drug Administration (FDA) has approved VYVGART

Hytrulo (efgartigimod alfa and hyaluronidase-qvfc) for the treatment of adult patients with chronic inflammatory demyelinating polyneuropathy

(CIDP). VYVGART Hytrulo is approved for CIDP as a once weekly 30-to-90 second subcutaneous injection. It is the first and only neonatal

Fc receptor (FcRn) blocker approved for the treatment of CIDP.

to pursue our ambition to turn science into solutions for patients with severe autoimmunity," said Luc Truyen M.D., Ph.D., Chief

Medical Officer, argenx. "Patients have been waiting, and today argenx is delivering the first innovative treatment for CIDP in

more than 30 years. VYVGART Hytrulo is a precision tool that has been shown to drive meaningful benefits for patients. Today's

FDA approval means that CIDP patients have a transformational new treatment option and further affirms the therapeutic profile of VYVGART

Hytrulo and the potential of FcRn blockade in IgG-mediated autoimmune diseases."

debilitating, often progressive, immune-mediated neuromuscular disorder of the peripheral nervous system. Patients experience a range

of disabling mobility and sensory issues, including trouble standing from a seated position, pain and fatigue, and frequent tripping

or falling. Many patients become wheelchair bound and are unable to work as the disease progresses. Currently, 85% of patients require

ongoing treatment and nearly 88% of treated patients experience residual impairment and disability.

patients face many daily concerns and challenges, fear of disease progression should not be one of them. CIDP can be debilitating and

have significant impact on quality of life and many patients with CIDP require treatments that may be burdensome. The approval of this

promising new treatment option for CIDP may provide hope to patients that they can treat their disease beyond just managing symptoms.

CIDP patients deserve treatment options and we look forward to a future of choices for optimal and individualized care," said Lisa

Butler, Executive Director, GBS|CIDP Foundation.

a groundbreaking day for the treatment of CIDP. Existing treatments have been limited to corticosteroids and plasma-derived therapies.

These treatments, while effective for many patients, can be challenging for some patients to receive," said Jeffrey Allen, M.D.,

Professor, Department of Neurology,

of Minnesota and Principal Investigator in the ADHERE trial. "Today's approval of VYVGART Hytrulo gives doctors and patients

a new, safe and effective treatment option that may lessen the burden of treatment that some patients experience."

is based on the ADHERE Study, the largest clinical trial to date studying CIDP. In the ADHERE study, 69% (221/322) of patients

treated with VYVGART Hytrulo, regardless of prior treatment, demonstrated evidence of clinical improvement, including improvements in

mobility, function and strength. ADHERE met its primary endpoint (p<0.0001) demonstrating a 61% reduction (HR: 0.39 95% CI: 0.25;

0.61) in the risk of relapse versus placebo. Ninety-nine percent of trial participants elected to participate in the ADHERE open-label

extension. The safety results were generally consistent with the known safety profile of VYVGART in previous clinical studies and real-world

is also approved in the U.S. for the treatment of generalized myasthenia gravis (gMG) in adult patients who are anti-acetylcholine receptor

(AChR) antibody positive.

Access to VYVGART Hytrulo

to supporting access for patients to its medicines and VYVGART Hytrulo is expected to be available for patients in the U.S. immediately.

The typical patient will have an annual out-of-pocket cost similar to that of a VYVGART or VYVGART Hytrulo patient with gMG, or an IVIg

argenx has established

a patient support program, My VYVGART Path, which can help patients and HCPs navigate access. My VYVGART Path program resources include

disease and product education, access support and benefits verification, and financial assistance programs for eligible patients. More

information is available at VYVGART.com.

Conference Call Details

a conference call Friday, June 21, 2024, at 11:00 pm CET (5:00pm ET) to discuss the approval. A webcast of the live call and replay

may be accessed on the Investors section of the argenx website.

FDA-approved Important Safety Information below and full Prescribing Information for VYVGART Hytrulo for additional information.

What is VYVGART HYTRULO

(efgartigimod alfa and hyaluronidase-qvfc)?

is a prescription medicine used for the treatment of adult patients with chronic inflammatory demyelinating polyneuropathy (CIDP).

IMPORTANT SAFETY INFORMATION

HYTRULO if you have a serious allergy to efgartigimod alfa, hyaluronidase, or any of the other ingredients in VYVGART HYTRULO. VYVGART

HYTRULO can cause serious allergic reactions and a decrease in blood pressure leading to fainting.

VYVGART HYTRULO may cause serious

side effects, including:

if you have signs or symptoms of an infection, allergic reaction, or infusion-related reaction. These can happen while you are receiving

your 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 HYTRULO, tell

What are the common side effects

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,

These are not all the possible side

effects of 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.

Please see the full Prescribing Information

for VYVGART HYTRULO and talk to your doctor.

About ADHERE Trial Design

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.

About VYVGART Hytrulo (efgartigimod

alfa and hyaluronidase-qvfc)

is a subcutaneous combination of efgartigimod alfa, a human IgG1 antibody fragment marketed for intravenous use as VYVGART, and recombinant

human hyaluronidase PH20 (rHuPH20), Halozyme's ENHANZE drug delivery technology to facilitate subcutaneous injection

delivery of biologics. In binding to the neonatal Fc receptor (FcRn), VYVGART Hytrulo results in the reduction of circulating IgG. It

is the first-and-only approved FcRn blocker administered by subcutaneous injection.

is the proprietary name in the U.S. for subcutaneous efgartigimod alfa and recombinant human hyaluronidase PH20. It may be marketed under

different proprietary names following approval in other regions.

About Chronic Inflammatory Demyelinating

Chronic inflammatory

demyelinating polyneuropathy (CIDP) is a rare and serious autoimmune disease of the peripheral nervous system. Although confirmation

of disease pathophysiology is still emerging, there is increasing evidence that IgG antibodies play a key role in the damage to the peripheral

nerves. People with CIDP experience fatigue, muscle weakness and a loss of feeling in their arms and legs that can get worse over time

or may come and go. These symptoms can significantly impair a person's ability to function in their daily lives. Without treatment,

one-third of people living with CIDP will need a wheelchair. There are approximately 24,000 patients in the U.S. currently receiving