Efgartigimod SC for Myositis

(ALKIVIA+ Trial)

Enrolling by invitation at 81 trial locations

Overseen By Sabine s Coppieters, MD

Age: 18+

Sex: Any

Trial Phase: Phase 3

Sponsor: argenx

Disqualifiers: Major surgery, Malignancy, Myositis, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Pivotal Trial (Near Approval) This treatment is in the last trial phase before FDA approval

Prior Safety Data This treatment has passed at least one previous human trial

Approved in 4 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: Unknown

Duration: 52 weeks

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial evaluates the safety and tolerability of efgartigimod, an experimental drug, for individuals with myositis, a condition that causes muscle inflammation. Researchers are also assessing the drug's effectiveness in participants from a related study. Eligible participants must have completed the previous trial and be able to adhere to the study rules. They will receive efgartigimod alongside their current treatments to observe long-term effects. As a Phase 3 trial, this study represents the final step before FDA approval, offering participants the opportunity to contribute to potentially bringing a new treatment to market.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the study team or your doctor.

Is there any evidence suggesting that efgartigimod is likely to be safe for humans?

Research has shown that efgartigimod is generally safe for patients. The number of people experiencing side effects from the treatment was similar to those in other studies, indicating that most patients did not encounter unexpected problems.

Earlier results also demonstrated that efgartigimod improved disease symptoms and was safe to use, meaning patients felt better without facing new health issues from the treatment.

Efgartigimod is already approved in the United States for treating generalized myasthenia gravis, a long-term autoimmune disorder. This approval suggests a strong safety record for the treatment.

In summary, efgartigimod appears safe for those considering joining this trial. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising for myositis?

Efgartigimod is unique because it offers a new approach to treating myositis by targeting the neonatal Fc receptor (FcRn). While most treatments for myositis, like corticosteroids and immunosuppressants, suppress the immune system broadly, efgartigimod works by specifically reducing the levels of harmful antibodies that contribute to the condition. Additionally, this treatment is administered subcutaneously, which is more convenient compared to the intravenous administration required for many existing therapies. Researchers are excited because this targeted mechanism could lead to fewer side effects and improved outcomes for patients.

What evidence suggests that efgartigimod might be an effective treatment for myositis?

Research shows that efgartigimod, which participants in this trial will receive, may help treat conditions like myositis. It has already received approval for generalized myasthenia gravis, a condition that weakens muscles, demonstrating its ability to improve muscle-related symptoms. Early studies in myositis have also shown positive results, indicating that efgartigimod might reduce inflammation and enhance muscle function. These findings suggest that efgartigimod could benefit people with myositis and support further research into its use for this condition. ^{1 2 5 6 7}

Are You a Good Fit for This Trial?

This trial is for adults with active Idiopathic Inflammatory Myopathy (IIM) who completed the ARGX-113-2007 study. Participants must be able to consent, follow the study plan, and use contraception if of childbearing potential. Exclusions include planned major surgery, new medical conditions that risk safety or skew results, known drug hypersensitivity, any cancer except basal cell skin carcinoma, or previous discontinuation from the related trial.

Inclusion Criteria

Has completed trial ARGX-113-2007

Being capable of providing signed informed consent and complying with protocol requirements

Agrees to use contraceptive measures consistent with local regulations and women of childbearing potential must have a negative urine pregnancy test at baseline before receiving the investigational medicinal product

Exclusion Criteria

I have not developed any new or recurrent cancer, except for basal cell skin cancer.

Known hypersensitivity reaction to investigational medicinal product or 1 of its excipients

Permanent discontinuation of IMP in ARGX-113-2007, or met the permanent discontinuation criteria at the rollover visit

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive efgartigimod PH20 SC on top of background treatment

52 weeks

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Open-label extension

Long-term safety, tolerability, and efficacy of efgartigimod PH20 SC are assessed

Long-term

What Are the Treatments Tested in This Trial?

Interventions

• Efgartigimod

Trial Overview The trial tests long-term safety and effectiveness of a subcutaneous injection called efgartigimod PH20 SC in those with IIM. It's for people who've had it before in an earlier phase of research and looks at how well they tolerate it over time as well as its ongoing benefits.

How Is the Trial Designed?

Group I: EFG PH20 SC Experimental Treatment 1 Intervention

participants receiving efgartigimod PH20 SC on top of background treatment

Efgartigimod is already approved in European Union, United States, Canada, Japan for the following indications:

Approved in European Union as Vyvgart for:

• Generalized Myasthenia Gravis (gMG)

Approved in United States as Vyvgart for:

• Generalized Myasthenia Gravis (gMG)
• Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)

Approved in Canada as Vyvgart for:

• Generalized Myasthenia Gravis (gMG)

Approved in Japan as Vyvgart for:

• Generalized Myasthenia Gravis (gMG)

Who Is Running the Clinical Trial?

argenx

Lead Sponsor

Trials

76

Recruited

11,500+

Tim Van Hauwermeiren

argenx

Chief Executive Officer since 2008

B.Sc. and M.Sc. in Bioengineering from Ghent University, Executive MBA from The Vlerick School of Management

Dr. Peter Ulrichts

argenx

Chief Medical Officer since 2023

MD from Maastricht University, PhD in Molecular Immunology from Maastricht University

Published Research Related to This Trial

Efgartigimod, a new treatment that reduces pathogenic IgG autoantibodies, showed promising results in three patients with both stiff-person syndrome (SPS) and myasthenia gravis (MG) over a 12-week treatment period, leading to symptom improvement.

This study suggests that efgartigimod could be a potential therapy for SPS and other autoimmune neurological disorders, as it demonstrated efficacy in alleviating symptoms associated with both conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efgartigimod beyond myasthenia gravis: the role of FcRn-targeting therapies in stiff-person syndrome. Di Stefano, V., Alonge, P., Rini, N., et al.[2023]

Intravenous immunoglobulin (IVIg) treatment significantly improved clinical scores in patients with Stiff-Person Syndrome (SPS) and dermatomyositis (DM) over 3 months, while scores returned to baseline when switched to placebo, indicating its efficacy in these conditions.

In addition to clinical improvements, IVIg treatment led to notable changes in tissue markers, including reduced inflammation and alterations in immunoregulatory genes, demonstrating its mechanism of action in restoring tissue health.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intravenous immunoglobulin in patients with anti-GAD antibody-associated neurological diseases and patients with inflammatory myopathies: effects on clinicopathological features and immunoregulatory genes. Dalakas, MC.[2018]

Efgartigimod effectively reduces levels of pathogenic anti-HMGCR autoantibodies and total IgG in a humanized mouse model of immune-mediated necrotizing myopathies, demonstrating significant therapeutic potential.

In both preventive and therapeutic settings, efgartigimod not only prevents muscle fiber necrosis but also promotes muscle fiber regeneration, leading to restored muscle strength, which supports further clinical trials in patients with IMNM.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efgartigimod restores muscle function in a humanized mouse model of immune-mediated necrotizing myopathy. Julien, S., van der Woning, B., De Ceuninck, L., et al.[2023]

Efgartigimod, a first-in-class neonatal Fc receptor antagonist, received its first approval in the USA in December 2021 for treating generalized myasthenia gravis in adults who are positive for anti-acetylcholine receptor antibodies.

The drug is also being evaluated for other autoimmune diseases and has been approved in Japan for generalized myasthenia gravis patients regardless of antibody status, indicating its potential broad application in autoimmune conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efgartigimod: First Approval. Heo, YA.[2022]

Serum levels of B cell activating factor (BAFF) were significantly higher in patients with myositis compared to healthy controls, suggesting a potential role in the disease's pathology.

Higher BAFF levels were associated with specific autoantibodies, particularly anti-Jo-1, and correlated with muscle damage markers, indicating that BAFF may serve as a therapeutic target in myositis treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Increased serum levels of B cell activating factor (BAFF) in subsets of patients with idiopathic inflammatory myopathies. Krystufková, O., Vallerskog, T., Helmers, SB., et al.[2009]

Efgartigimod, a human IgG1 antibody, significantly improved symptoms in patients with generalized myasthenia gravis, with 68% of treated patients showing a meaningful response compared to only 30% in the placebo group, indicating strong efficacy.

The treatment was well tolerated, with similar rates of adverse events between efgartigimod and placebo groups, suggesting it is a safe option for patients, with no deaths reported during the trial.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety, efficacy, and tolerability of efgartigimod in patients with generalised myasthenia gravis (ADAPT): a multicentre, randomised, placebo-controlled, phase 3 trial. Howard, JF., Bril, V., Vu, T., et al.[2022]

In a study involving 51 patients with inclusion body myositis (IBM) and 19 healthy donors, researchers found an expansion of KLRG1+ T cells, particularly in the effector memory re-expressing CD45RA (TemRA) and effector memory T cell (Tem) compartments, indicating a potential target for therapy.

The study revealed that KLRG1 expression in CD8+ T cells increased with differentiation, suggesting that targeting these highly differentiated T cells could be a promising approach in treating IBM, while NK cell populations remained unchanged between patients and healthy individuals.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Immunophenotyping of Inclusion Body Myositis Blood T and NK Cells. Goyal, NA., Coulis, G., Duarte, J., et al.[2023]

Efgartigimod alfa is the first neonatal Fc receptor antagonist approved for treating generalized myasthenia gravis (gMG), showing significant and rapid improvements in muscle strength and quality of life in a phase 3 trial with a placebo group.

The treatment was generally well tolerated, with most side effects being mild to moderate, indicating a favorable safety profile for patients with gMG.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efgartigimod Alfa in Generalised Myasthenia Gravis: A Profile of Its Use. Heo, YA.[2023]

Efgartigimod was found to be safe and well-tolerated in a phase 2 study involving 24 patients with generalized myasthenia gravis, with no serious adverse events reported.

The treatment led to a significant reduction in pathogenic IgG autoantibodies and resulted in a rapid and long-lasting improvement in disease symptoms for 75% of patients, suggesting its potential as an effective therapy for myasthenia gravis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Randomized phase 2 study of FcRn antagonist efgartigimod in generalized myasthenia gravis. Howard, JF., Bril, V., Burns, TM., et al.[2020]

Citations

1. argenx.com argenx.com/news/2025/press-release-3097206

argenx Presents New Efgartigimod Data at EULAR 2025 ... argenx Presents New Efgartigimod Data at EULAR 2025 Highlighting Positive Phase 2 Proof-of-Concept Results in Myositis and Sjogren's Disease.

2. clinicaltrials.gov clinicaltrials.gov/study/NCT05523167

NCT05523167 | A Study to Investigate the Efficacy and ... This study's purpose is to measure the treatment response from efgartigimod PH20 SC compared with placebo in participants with Idiopathic Inflammatory Myopathy ...

3. argenx.com argenx.com/news/2025/press-release-3176635

argenx Presents New Data at AANEM and MGFA ... “The ADAPT SERON trial showed that efgartigimod generated tangible improvements in daily functioning, marking an important advancement for the ...

4. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8855644/

Efgartigimod: First Approval - PMC In December 2021, intravenous efgartigimod received its first approval in the USA for the treatment of generalized myasthenia gravis in adults.

5. clinicaltrials.gov clinicaltrials.gov/study/NCT05979441

NCT05979441 | A Study to Assess the Long-term Safety ... The purpose of this study is to measure the long-term safety and tolerability of efgartigimod PH20 SC in adult participants with IIM who previously ...

6. the-rheumatologist.org the-rheumatologist.org/article/promising-phase-2-results-for-efgartigimod-alfa-fcab-in-adults-with-primary-sjogrens-disease/

Promising Phase 2 Results for Efgartigimod alfa-fcab in ... Its results demonstrated significant improvements in systemic disease activity and patient symptoms, as well as a favorable safety profile.1. At ...

7. clinicaltrials.ucsf.edu clinicaltrials.ucsf.edu/trial/NCT05979441

UCSF Myositis Trial → Long-term Safety and Efficacy of a ... The purpose of this study is to measure the long-term safety and tolerability of efgartigimod PH20 SC in adult participants with IIM who previously ...