Research Shows Efgartigimod Costs Are Far Higher Than Therapeutic Plasma Exchange for Myasthenia Gravis

Research findings presented at the American Society of Health-Systems Pharmacists (ASHP) Midyear 2024 Clinical Meeting show that treatment of myasthenia gravis with efgartigimod alfa (Vyvgart; argenx) is far more expensive than traditional therapies such as therapeutic plasma exchange (TPE) with or without intravenous immunoglobulin (IVIG), presenting a potentially significant barrier for patients.¹

Nurse hanging an IV bag | Image credit: Halfpoint | stock.adobe.com

Myasthenia gravis is a chronic neuromuscular disorder, causing weakness in voluntary muscles such as those connecting to the bones and muscles in the face, throat, and diaphragm. These muscles are crucial for breathing, swallowing, and facial movements, although the degree of muscle weakness can vary greatly among patients.²

The condition affects both men and women and occurs across all racial and ethnic groups. It most commonly impacts women younger than age 40 and men older than 60, but it can occur at any age, including in childhood. It is caused by an error in nerve signals to the muscles, specifically when communication between the nerve and muscle is interrupted at the neuromuscular junction.²

There is currently no known cure for myasthenia gravis. Options include anticholinesterase medications to slow the breakdown of acetylcholine at the neuromuscular junction; thymectomy to remove the thymus gland, possible rebalancing the immune system; complement inhibition; immunosuppressive drugs; and plasmapheresis and IVIG. The latter options are used in severe cases to remove destructive antibodies attacking the neuromuscular junction, although they are typically only effective for a brief period.²

Efgartigimod alfa was initially approved by the FDA in 2021. It is a neonatal Fc receptor blocker for the treatment of generalized myasthenia gravis in adults who are anti-acetylcholine receptor (AChR) antibody positive.³

The approval was based on findings from the global phase 3 ADAPT trial, which showed that significantly more anti-AChR antibody–positive participants with generalized myasthenia gravis were responders on the Myasthenia Gravis Activities of Daily Living (MG-ADL) scale following treatment with efgartigimod alfa compared with placebo (68% vs 30%; p<0.0001). Responders were defined as having at least a 2-point reduction on the MG-ADL scale sustained for 4 or more consecutive weeks during the first treatment cycle.³

The treatment is administered via infusion with a recommended dose of 10 mg/kg administered over the course of 1 hour. It is typically administered once weekly for 4 weeks. For individuals weighting 120 kg or more, the recommended dose of 1200 mg per infusion.³

“Efgartigimod alfa is a treatment for maintenance of myasthenia gravis. However, TPE and TPE with IVIG is for an acute exacerbation,” explained Ethan Encinias, a PharmD candidate at the Belmont Pharmacy College of Pharmacy and Health Sciences. “So, when [patients] are in that pain crisis with myasthenia gravis and their muscles are contracting, when they get admitted into the hospital for an acute exacerbation, they will go through plasmapheresis or TPE, and theyn they’ll add on IVIG.”

Importantly, efgartigimod alfa and TPE plus IVIG have significantly different costs. According to the research presented at ASHP Midyear, the calculated price for a single infusion cycle of efgartigimod alfa, including a conservative hospital markup of 1.5% to 3%, ranged between $93,597.84 and $187,195.65 per patient, depending on the average wholesale price and weight-adjusted dosing data. This estimate was consistent across sexes with minimal variation due to minor differences in average body weight.¹

The price per procedure of TPE included the costs of peripherally inserted central catheter ($286.04), line ($286), and plasma replacement (average $269 per unit). The estimated price for a typical course of 6 TPE procedures ranged from $17,856 for men and $14,628 for women. When TPE was combined with IVIG, the additional cost averaging $915.30 per infusion increased the total treatment cost. The price for 3 to 6 procedures of TPE with IVIG ranged from $9843.3 to $18,771.30 for men and between $8229.30 to $15,543 for women.¹

The study authors noted that the higher costs of efgartigimod alfa are primarily driven by its status as a newly approved, brand-name therapy without a generic alternative, whereas TPE is an established treatment and has lower procedural costs. Although efgartigimod alfa has a novel approach that could significantly improve care for patients with myasthenia gravis, the findings raise significant concerns about cost-effectiveness and accessibility.¹

“I would like to see further [research] done based off of lifetime therapy with efgartigimod alfa, to really see if that cost is justified over lifetime data for patients with myasthenia gravis,” Encinias said. “Right now, even though it works extremely well and the data is very good for efgartigimod alfa, the cost is the main [obstacle].”¹

REFERENCES

1. Encinias E, Booth G. Evaluating Cost for Generalized Myasthenia Gravis Treatment. Poster. Presented at: American Society of Health-Systems Pharmacists (ASHP) Midyear 2024 Clinical Meeting. New Orleans, LA. December 10, 2024.

2. Myasthenia Gravis. National Institute of Neurological Disorders and Stroke. Updated July 19, 2024. Accessed December 18, 2024. https://www.ninds.nih.gov/health-information/disorders/myasthenia-gravis#

3. Arakelians S. Efgartigimod Alfa Provides Much-Needed Treatment Options for Patients With Generalized Myasthenia Gravis. Pharmacy Times. August 29, 2024. Accessed December 18, 2024. https://www.pharmacytimes.com/view/efgartigimod-alfa-provides-much-needed-treatment-options-for-patients-with-generalized-myasthenia-gravis