The U.S. Food and Drug Administration (FDA) has approved a new pre-filled syringe formulation of efgartigimod (VYVGART Hytrulo) for self-injection in adult patients with generalized myasthenia gravis (gMG) who are anti-acetylcholine receptor (AChR) antibody positive and those with chronic inflammatory demyelinating polyneuropathy (CIDP).
This approval marks a significant advancement in treatment options for patients with these autoimmune neurological disorders, offering greater convenience and flexibility compared to traditional intravenous (IV) infusions or healthcare facility-administered injections.
Enhanced Patient Autonomy with Self-Administration
The new pre-filled syringe allows patients to self-administer their medication after proper instruction in subcutaneous injection technique. The single-dose injection takes only 20-30 seconds to administer and can be performed by patients, caregivers, or healthcare professionals.
"This new self-injection option will lead to more convenient and flexible administration for patients, empowering them to decide when and where they receive treatment," said Dr. Beth Stein, Director of Neuromuscular Diseases at St. Joseph's Health. "A ready-to-use option enhances patient independence and reduces the time required for treatment, making disease management and control more seamless."
The approval reflects argenx's commitment to improving treatment experiences for patients with severe autoimmune diseases. Luc Truyen, MD, PhD, Chief Medical Officer at argenx, emphasized that the new formulation provides patients with "more freedom and flexibility to self-administer VYVGART Hytrulo" while maintaining the medication's "favorable safety profile and strong efficacy."
Scientific Basis for Approval
The approval was supported by data from studies evaluating the bioequivalence of the pre-filled syringe formulation to VYVGART Hytrulo in a vial. Human factors validation studies demonstrated that participants with gMG or CIDP, or their caregivers, could safely and successfully prepare and administer the medication with the pre-filled syringe.
The pre-filled syringe was developed through argenx's exclusive partnership with Halozyme's ENHANZE drug delivery technology, which enables rapid, high-volume delivery of biologics that are typically administered via infusion.
Previous clinical trials supporting the efficacy of efgartigimod include:
- The phase 3 ADAPT-SC study, which demonstrated that subcutaneous efgartigimod achieved a mean IgG reduction of 66.4% by day 29, noninferior to the 62.2% seen with IV administration
- The phase 3 ADHERE trial for CIDP, which showed that VYVGART Hytrulo significantly reduced relapse risk by 61% compared with placebo (P = .00039)
- The ADAPT OCULUS trial, a phase 3 study in patients with ocular MG
Mechanism of Action and Dosing
Efgartigimod is a first-in-class neonatal Fc receptor (FcRn) blocker designed to reduce levels of pathogenic IgG autoantibodies by preventing their recycling in the body. The medication works by binding to FcRn, resulting in the reduction of circulating IgG autoantibodies that cause the symptoms of gMG and CIDP.
VYVGART Hytrulo's approved indication is a 1008-mg fixed dose administered over 30 to 90 seconds in cycles of once-weekly injections for 4 weeks. Subsequent treatment cycles are based on clinical evaluation, though the safety of initiating cycles sooner than 50 days from the start of a previous treatment cycle has not been established.
Patient Community Response
Patient advocacy organizations have welcomed the new administration option. Samantha Masterson, President and CEO of the Myasthenia Gravis Foundation of America, noted that "this new self-injection option is a natural progression, empowering individuals to take control of their treatment and working toward achieving a greater sense of normalcy in their lives."
Lisa Butler, Executive Director of the GBS-CIDP Foundation, highlighted the impact for CIDP patients: "The daily burden of CIDP from both the symptoms of the disease and interruption to daily life creates profound unseen challenges for patients. Effective new treatments that reduce the need for frequent clinic visits are a welcome option for active patients seeking to regain time and a sense of normalcy in their daily routine."
Global Regulatory Status
While now approved in the United States, the pre-filled syringe formulation is still under regulatory review in other regions. The Committee for Medicinal Products for Human Use (CHMP) has given a positive recommendation for approval, with the European Union expected to make a decision in the first half of 2025. Japan and Canada are also expected to make regulatory decisions in the second half of 2025.
Argenx is also developing an autoinjector version of the therapy, expected to launch around 2027, further expanding administration options for patients.
Safety Considerations
The company notes that VYVGART Hytrulo may cause serious adverse effects, including increased risk of infection, allergic reactions, and infusion-related reactions. Common side effects include respiratory tract infections, headaches, urinary tract infections, and injection site reactions.
Patients are advised to monitor for signs of infection (fever, cough, sore throat, painful urination), allergic reactions (rash, swelling, difficulty breathing), and infusion-related reactions (high blood pressure, chills, pain).
Patient Support Program
To facilitate access to the new formulation, argenx offers a patient support program called My VYVGART Path. The program provides disease and product education, access support, benefits verification, and financial assistance programs for eligible patients.
This approval represents a significant advancement in the treatment landscape for patients with gMG and CIDP, offering a more convenient administration option while maintaining the established efficacy and safety profile of efgartigimod.
