Express 66.4% of patients improved their symptoms! Myasthenia gravis drugs are submitted to the BLA

argenx has announced that it has submitted its subcutaneous injection efgartigimod (1000 mg efgartigimod-PH20) to the U.
S.
FDA for the treatment of adult patients with systemic myasthenia gravis (gMG)
for a biologic license (BLA).
The BLA application is based on the results
of a non-inferiority clinical trial of efgartigimod subcutaneous injection and the intravenous drug Vyvgart (efgartigimod alfa-fcab).

Myasthenia gravis is a rare chronic autoimmune disease
.
The patient's own pathogenic immunoglobulin G (IgG) antibody disrupts synaptic transmission between nerves and muscles, causing weak and potentially life-threatening muscle weakness
.
More than 85% of patients with myasthenia progress to generalized myasthenia gravis within 24 months of onset, resulting in extreme fatigue and difficulty
facial expressions, speech, swallowing, and movement.
In patients with myasthenia gravis, 85% have confirmed acetylcholine receptor (AChR) antibodies
.

Efgartigimod subcutaneous injection combines efgartigimod with recombinant human hyaluronidase PH20 (rHuPH20
).
Developed by Halozyme Therapeutics, rHuPH20 degrades hyaluronic acid in the body to aid in the penetration and absorption of subcutaneous drugs, providing patients with additional treatment options
.
The main active ingredient in subcutaneous injections, efgartigimod, is an antibody fragment
that targets the Fc receptor (FcRn).
FcRn receptors prevent the degradation of IgG, so efgartigimod is able to block the IgG recycling process by preventing IgG from binding to FcRn, resulting in faster depletion of IgG antibodies mediating autoimmune diseases, thereby alleviating disease symptoms
.
Developed by argenx with efgartigimod as the main active ingredient, Vyvgart was approved in December last year to treat adult myasthenia gravis patients with
AChR antibody-positive intravenous injections once a week.
This is the first FDA-approved FcRn blocker
.
Zai Pharma has partnered with argenx to acquire a development and commercialization interest
in this innovative therapy in Greater China.

The BLA submission is mainly based on the results
of the ADAPT-SC trial.
The trial was a multicenter, randomized, open-label Phase 3 clinical trial with 110 patients enrolled to test whether efgartigimod subcutaneous injection (1000 mg) was not inferior to Vyvgart (10 mg/kg) in the treatment of
patients with myasthenia gravis.
The pharmacodynamic effect was assessed by a percentage change in total IgG content in the patient compared to baseline at day 29, which was the primary endpoint
of the trial.
The decrease in total in vivo IgG content has been shown in previous Phase 2 trials to correlate
with clinical benefit in patients.

The trial reached the primary endpoint of the non-inferiority criterion (p<0.
0001), with mean total IgG levels reduced by 66.
4% relative to baseline at day 29 in the subcutaneous formulation group compared to 62.
2%
in the intravenous formulation group.
Efficacy results were consistent
across patients who included positive and negative AChR antibodies.
In addition, the trial reached other key secondary endpoints, consistent with the clinical efficacy findings observed in the Phase 3 clinical trial of intravenous infusion preparations, including responses in the stellarity gravist daily living activities (MG-ADL) and quantitative myasthenia gravis (QMG), respectively
, in patients in the subcutaneous injection group.
Its safety profile is also consistent with previous studies and is generally well tolerated, with the most common adverse event being injection site reaction (ISR
).

"Our vision for the Myasthenia gravis program is to give patients with this often overlooked debilitating disease a wider range of treatment options
.
Every patient's situation is different, which is why we are excited about the possibility that different dosages and dosing modalities can be offered to meet patient needs," said Mr.
Tim Van Hauwermeiren, CEO of argenx.
"We look forward to working with regulators during the review process to bring another potential 'first-in-class' option for the disease to patients
.
" ”

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