From the Guidelines
Efgartigimod is used to treat generalized myasthenia gravis (gMG) in adults, particularly those who test positive for the anti-acetylcholine receptor, with a recently FDA-approved formulation, efgartigimod alfa-fcab. The use of efgartigimod is based on its ability to reduce pathogenic IgG antibodies, including the autoantibodies responsible for gMG symptoms, by binding to the neonatal Fc receptor (FcRn) and preventing it from recycling IgG antibodies 1. Key points to consider when using efgartigimod include:
- It is an alternative treatment option for patients who show minimal response to pyridostigmine bromide or other first-line treatments
- It has been shown to be effective in reducing symptoms of gMG, with about 66% to 85% of patients showing a positive response to immunosuppressive therapy, including efgartigimod alfa-fcab 1
- Thymectomy may be indicated in some cases, particularly in the presence of thymoma, and may substantially reduce symptoms for certain subpopulations with myasthenia gravis 1
- Regular monitoring by a healthcare provider is necessary to assess treatment response and adjust dosing if needed
- Common side effects may include injection site reactions, headache, and upper respiratory tract infections, although the specific formulation and dosing regimen may impact the risk of these side effects 1.
From the Research
Use of Efgartigimod
- Efgartigimod is a neonatal fragment crystallizable receptor (FcRn) antagonist indicated for the treatment of generalized myasthenia gravis (gMG) in adults who are acetylcholine receptor (AChR) antibody positive (Ab+) 2.
- It is approved for both intravenous (IV) and subcutaneous (SC) use, providing effective and generally well-tolerated treatment options for adults with AChR Ab+ gMG 2.
- Efgartigimod has been shown to improve myasthenia gravis symptoms, reduce disease burden, and improve health-related quality of life (HRQOL) in patients with gMG 2, 3.
Efficacy in Myasthenic Crisis
- Efgartigimod has been found to be effective and well-tolerated in patients with myasthenic crisis (MC), with rapid action in facilitating the weaning process and a good safety profile 4.
- In a prospective case series, all patients with MC who received efgartigimod were successfully weaned from ventilation, with significant improvements in MG-ADL scores and reductions in corticosteroid doses 4.
Pharmacokinetics and Pharmacodynamics
- The pharmacokinetic, pharmacodynamic, and safety profiles of efgartigimod in Chinese participants were similar to those in non-Chinese participants, with effective reductions in total IgG levels 5.
- Efgartigimod has been shown to decrease IgG recycling and increase degradation, resulting in lower IgG concentration and improved muscle function and strength across all muscle groups 3.
Clinical Trials
- A phase 2 study found efgartigimod to be safe and well-tolerated in patients with gMG, with rapid and long-lasting disease improvement in 75% of patients 6.
- The ADAPT study demonstrated significant improvements in MG-ADL and QMG scores with efgartigimod treatment, with benefits observed across all muscle groups 3.