Efgartigimod PH20 SC Clinical Trials

What Is Efgartigimod PH20 SC?

Efgartigimod PH20 SC is an FDA-approved medication for the ongoing (chronic) treatment of generalized Myasthenia Gravis (gMG) in adult patients who are anti-acetylcholine receptor antibody positive. This medication is administered as a subcutaneous injection, often using a prefilled syringe. It is also being investigated in clinical trials for its potential use in other conditions. The first trial involving efgartigimod began on December 5, 2019, and the latest trial is projected to conclude on May 19, 2026. Across all studies, a total of 6,711 participants have been enrolled to date.

Uses and Conditions Under Study

Efgartigimod PH20 SC is primarily studied for conditions related to Myasthenia Gravis. This includes Generalized Myasthenia Gravis (gMG), Myasthenia Gravis, gMG specifically, and AChR-Ab Seropositive Generalized Myasthenia Gravis. These related conditions are being investigated across 27 trials, exploring how efgartigimod can help manage the symptoms of this autoimmune neuromuscular disorder.

The drug is also under investigation for other autoimmune conditions. Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), another neurological disorder, is being studied in 5 trials. Additionally, Primary Immune Thrombocytopenia, a blood disorder, is the focus of 4 trials, and Bullous Pemphigoid, a blistering skin condition, is being examined in 2 trials. Some studies are also broadly investigating efgartigimod itself in 3 trials, likely to understand its general properties or explore new applications.

Dosing

Efgartigimod PH20 SC is primarily administered as a subcutaneous injection, typically using a prefilled syringe (PFS). For certain participants, such as those aged 12 to <18 years with a body weight of 50 kg or less, the study drug may be administered by vial and syringe. An investigational dosage regimen has included 10 mg/kg given once a week for a duration of 25 weeks.

In addition to the subcutaneous form, efgartigimod has also been studied as an intravenous (IV) infusion. Clinical trials have explored both subcutaneous and intravenous forms for elderly patients with Generalized Anti-AChR Myasthenia Gravis. Studies are also examining the drug's use in patients with varying degrees of renal function, including mild, moderate, and severe renal impairment, as well as those with normal renal function, to understand appropriate dosing adjustments.

Side Effects

In clinical trials, patients taking Efgartigimod PH20 SC reported various side effects. The most frequently observed side effect was blood in urine, which occurred in 33.2% of patients receiving Efgartigimod PH20 SC, compared to 32.2% of patients on placebo. Other common side effects, particularly those observed more often with Efgartigimod PH20 SC than with placebo, included:

• Headache: 15.4% of patients taking Efgartigimod PH20 SC experienced headache, compared to 11.7% on placebo.
• Contusion (bruising): 15.2% of patients on Efgartigimod PH20 SC experienced contusion, compared to 14.4% on placebo.
• Hypertension (high blood pressure): 13.7% of patients on Efgartigimod PH20 SC experienced hypertension, compared to 4.1% on placebo.
• Mouth haemorrhage: 11.7% of patients on Efgartigimod PH20 SC experienced mouth haemorrhage, compared to 11.3% on placebo.
• Injection site erythema (redness at the injection site): 7.5% of patients on Efgartigimod PH20 SC experienced injection site erythema, compared to 2.1% on placebo.

Currently Recruiting Trials

Research into Efgartigimod PH20 SC is actively underway, with numerous clinical trials recruiting participants to explore its potential across a range of autoimmune conditions. These studies aim to understand how well the treatment works, its safety, and how it might improve the quality of life for patients.

• A Phase 4 study, NCT06909214, is evaluating the clinical outcomes of Efgartigimod PH20 SC in adults recently diagnosed with generalized myasthenia gravis (gMG). This study is recruiting 30 participants to measure their response to treatment over 51 weeks.
• For individuals with systemic sclerosis, a Phase 2 study (NCT06655155) is assessing the efficacy and safety of Efgartigimod PH20 SC compared to a placebo. This trial seeks to enroll 81 adults.
• Another Phase 2 study, NCT06503731, is investigating the safety, tolerability, and efficacy of Efgartigimod PH20 SC, delivered via a prefilled syringe, in 30 kidney transplant recipients experiencing antibody-mediated rejection.
• Pediatric patients with generalized myasthenia gravis are the focus of a Phase 2/Phase 3 study (NCT06392386). This trial is enrolling 12 children between 2 and 18 years of age to determine the appropriate dose of Efgartigimod PH20 SC.
• The long-term safety and efficacy of a subcutaneous formulation of Efgartigimod are being studied in adults with active idiopathic inflammatory myopathy in a Phase 3 trial (NCT05979441). This study plans to enroll 240 participants.
• A long-term safety study (NCT05374590) is evaluating both intravenous and subcutaneous formulations of Efgartigimod, including Efgartigimod PH20 SC, in 12 children with generalized myasthenia gravis who previously participated in other studies.
• A worldwide safety study (NCT06299748) is collecting data on maternal, fetal, and infant outcomes following exposure to Efgartigimod or Efgartigimod PH20 SC during pregnancy and/or breastfeeding, with an enrollment target of 279 women.
• For elderly patients with generalized anti-AChR myasthenia gravis, a Phase 4 study (NCT07072988) is evaluating the benefit of reducing steroid use when treated with either IV or SC Efgartigimod. This study aims to enroll 50 participants.
• A Phase 3 comparative study (NCT07217587) is assessing the efficacy of Efgartigimod against nipocalimab in 115 participants with generalized myasthenia gravis.

Where to Participate

Clinical trials for Efgartigimod PH20 SC are widely accessible across the United States, with 111 sites located in 72 cities across 33 states. This broad reach helps ensure that many patients have the opportunity to participate in research.

Some of the top cities with multiple recruiting sites include:

• Chicago, Illinois (6 sites)
• Columbus, Ohio (5 sites)
• Detroit, Michigan (4 sites)
• Austin, Texas (4 sites)
• Boston, Massachusetts (4 sites)
• Chattanooga, Tennessee (3 sites)
• O'Fallon, Illinois (3 sites)
• Tampa, Florida (3 sites)
• Los Angeles, California (3 sites)
• Miami, Florida (3 sites)

Eligibility for these trials generally includes participants aged between 2 and 90 years, encompassing all genders. Healthy volunteers are typically not recruited for these studies, as the focus is on patients living with specific conditions, and children are eligible for some trials.

Development Timeline

The journey of Efgartigimod began on December 5, 2019, with the initiation of its first clinical trial. Since then, the development program has grown significantly, primarily driven by the sponsor argenx, which has overseen 48 of the 66 total trials.

Initially, research explored conditions such as IBS-C and hyperphosphatemia. However, the pipeline quickly expanded to investigate Efgartigimod's potential in a wide array of autoimmune disorders. Key areas of focus emerged, including generalized myasthenia gravis (gMG), primary immune thrombocytopenia (ITP), and chronic inflammatory demyelinating polyneuropathy (CIDP).

As development progressed, the scope broadened further to include conditions like IgG4-related disease, systemic sclerosis, idiopathic inflammatory myopathy, and antibody-mediated rejection in kidney transplant recipients. The drug has moved through various phases, with 24 trials reaching Phase 3 and 19 in Phase 2, demonstrating a strong commitment to advancing through the clinical development process. With a total enrollment of 6,711 participants across all trials, Efgartigimod continues to be studied for its ability to address unmet needs in autoimmune disease treatment, with the latest trial projected to conclude in 2026.