argenx Highlights Breadth of Autoimmune Pipeline with New Multifocal Motor Neuropathy Data at 2024 Peripheral Nerve Society Annual Meeting ARDA study data show potential for empasiprubart to drive functional improvement

argenx Highlights Breadth of Autoimmune Pipeline

with New Multifocal Motor Neuropathy Data at 2024 Peripheral Nerve Society Annual Meeting

ARDA study data show potential for empasiprubart

to drive functional improvement and reduced risk of relapse for multifocal motor neuropathy (MMN) patients

show durability of functional improvements with VYVGART Hytrulo (efgartigimod alfa and hyaluronidase-qvfc),

which is FDA approved for use in adults with chronic inflammatory demyelinating polyneuropathy (CIDP)

June 25, 2024 - 4:30pm EDT

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 new data from across the company's autoimmune pipeline

were presented at the 2024 Peripheral Nerve Society (PNS) Annual Meeting in Montr al, Quebec.

"argenx is on a mission to transform the

treatment of severe autoimmunity," said Luc Truyen, M.D., Ph.D., Chief Medical Officer, argenx. "We have established MMN

and CIDP as autoantibody-mediated diseases, and by developing novel medicines that precisely target disease biology, we are fulfilling

our mission to create truly transformative outcomes for patients. We are excited to present data for our novel therapies that may offer

benefits beyond symptom management - to safely help patients regain control of their lives without harsh side effects, residual

impairments, or treatments dependent on high frequency infusions. argenx continues to build scientific and clinical evidence that supports

the advancement of our innovative pipeline and shows the potential to expand therapeutic choices while reducing the risk of relapse and

accumulating disability."

Phase 2 ARDA Data Support Empasiprubart as

Novel Targeted Treatment for MMN

For the first time at a medical congress, argenx

presented Cohort 1 data from the Phase 2 ARDA study, which support proof of concept for empasiprubart as a potential new treatment option

for MMN, a chronic, progressive autoimmune disease with only one approved treatment option. ARDA is the largest interventional study

ADHERE Oral Presentation Highlights Consistent Sustained Efficacy

and Safety of VYVGART Hytrulo for Patients with CIDP

argenx also presented

new data from the pivotal ADHERE and open-label extension ADHERE+ studies evaluating VYVGART Hytrulo in patients with CIDP. The ADHERE

data supported the recent FDA approval of VYVGART Hytrulo as a safe and effective new treatment option for CIDP, demonstrating sustained

functional benefit across all disease scores regardless of disease stage or treatment history. 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.

VYVGART Hytrulo was approved on June 21,

2024, for the treatment of adult patients with CIDP by the U.S Food and Drug Administration (FDA).

About Multifocal Motor Neuropathy

Multifocal motor neuropathy (MMN) is a rare,

chronic autoimmune disease of the peripheral nervous system. The disease is characterized by slowly progressive, asymmetric muscle weakness

mainly of the hands, forearms and lower legs. MMN is often associated with the presence of anti-GM1 IgM autoantibodies, leading to activation

of the classical complement pathway, driving subsequent axon damage. High-dose IVIg is the only approved treatment for MMN and patients

typically experience disease progression despite therapy, indicating an unmet need for efficacious and better tolerated therapeutic options.

About Chronic Inflammatory Demyelinating Polyneuropathy

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.

Phase 2 ARDA Study Design

The Phase 2 ARDA study is a randomized, double-blinded,

placebo-controlled multicenter study to evaluate the safety and tolerability, efficacy, pharmacokinetics, pharmacodynamics, and immunogenicity

of two dose regimens of empasiprubart in adults with multifocal motor neuropathy (MMN). The study consists of an IVIg dependency and

monitoring period before 2:1 randomization into a double-blind treatment phase for 16-weeks. Two sequential cohorts of 27 MMN patients

receiving empasiprubart or placebo were enrolled investigating two different dose levels of empasiprubart. The primary endpoint is safety

and tolerability. Additional endpoints include time to IVIg retreatment, biomarker analyses of C2 levels, and changes in measurements

on key clinical efficacy scores (modified medical research council (mMRC)-14 sum score, grip strength, MMN-RODS) as well as several patient-reported

quality of life outcome measures.

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.

Empasiprubart (ARGX-117) is a first-in-class

humanized monoclonal antibody that binds C2 and blocks activation of both the classical and lectin pathways of the complement cascade,

leaving the alternative pathway intact for its antimicrobial properties. By blocking complement activity upstream of C3 and C5, empasiprubart

has the potential to reduce tissue inflammation and cellular damage, representing a broad pipeline opportunity across multiple severe

autoimmune indications. In addition to multifocal motor neuropathy, argenx is evaluating empasiprubart in delayed graft function following

kidney transplant and dermatomyositis.

About VYVGART Hytrulo (efgartigimod alfa

and hyaluronidase-qvfc)

VYVGART Hytrulo 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.

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

as VYVDURA in Japan and VYVGART SC in Europe.

See 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)?

VYVGART HYTRULO is a prescription medicine used

for the treatment of adult patients with chronic inflammatory demyelinating polyneuropathy (CIDP).

IMPORTANT SAFETY INFORMATION

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 HYTRULO can cause serious allergic

reactions and a decrease in blood pressure leading to fainting.

VYVGART HYTRULO may cause serious side effects,

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 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