SAN FRANCISCO — Most patients with generalized myasthenia gravis (gMG) who took efgartigimod for 18 months managed to cut their glucocorticoid use to low levels or stopped taking it entirely, according to newly updated retrospective cohort study.

Among 167 patients with gMG who were using chronic glucocorticoids at baseline as they began efgartigimod, 55% reached a dose of 5 mg/d or lower, a level linked to much less risk for long-term adverse effects, reported neurologist Neelam Goyal, of Stanford University School of Medicine, Palo Alto, California. And 30% of the 167 patients stopped use of the steroids entirely by 18 months.

“In this real-world cohort of chronic glucocorticoid users, 18 months of continuous efgartigimod therapy led to a significant and progressive reduction in glucocorticoid use while retaining improved MG-ADL [Myasthenia Gravis Activities of Daily Living scale] scores,” Goyal said.

The findings were presented on October 29 at American Association of Neuromuscular Electrodiagnostic Medicine (AANEM) 2025. Goyal and colleagues previously reported 12-month data in the Journal of the Neurological Sciences.

Reducing the Steroid Burden

Although glucocorticoids have long been a mainstay treatment for gMG, the investigators noted there is a lack of high quality evidence supporting their safety and efficacy.

The researchers pointed out that mortality, hospitalizations, and intensive care use increase with higher cumulative doses and longer exposure to glucocorticoids. Targeted therapies such as efgartigimod, an FcRn blocker approved by the FDA in 2021, aim to reduce the dependence on steroids.

“Evidence of glucocorticoid reduction is critical to support treatment decision-making with targeted therapies,” Goyal said.

To assess whether efgartigimod use was associated with reduced steroid dependence, researchers analyzed insurance claims from about 2200 patients with gMG who first received the drug in early 2023.

The final analysis included 167 patients who remained on efgartigimod continuously for 18 months (mean age, 60 years; 57% men). Common comorbidities included hypertension (47%), sleep disorders (28%), hyperlipidemia (26%), diabetes (25%), sleep apnea (23%), obesity (20%), gastroesophageal reflux disease (16%), and thyroid disorders (12%).

Patients were excluded if they were concurrently receiving eculizumab, rituximab, ravulizumab, rozanolixizumab, or zilucoplan. Eligible participants were required to have documented chronic glucocorticoid use for at least 1 year before starting efgartigimod.

“At baseline, the average daily dose of steroids was 16.6 mg, which went down to 12.8 at 6 months, and further down to 7.5 at 18 months,” Goyal reported, noting that all P values were < .05.

In addition, at baseline 13% of patients were taking the lowest glucocorticoid dose (0-5 mg/d), whereas another 13% were receiving 30 mg/d or more. After 18 months, roughly 30% had discontinued steroids altogether, and only 3% remained on doses above 30 mg/d.

For a subset of 88 patients matched with MG-ADL scores, clinical improvements were sustained alongside glucocorticoid reductions. Over 18 months, “the average mean MG-ADL in this population dropped rapidly after initial initiation by about 4 points and further dropped [reaching -4.9] by quarter six,” Goyal reported.

She noted that a key strength of the study was its large sample size and longitudinal follow-up, which reinforced earlier case-series findings showing reduced glucocorticoid use with efgartigimod.

However, she cautioned that claims-based analyses carry inherent limitations, including reliance on assumptions, possible coding errors, and incomplete data. She added that the study did not examine how clinicians manage glucocorticoid tapering during efgartigimod treatment — an area that will require other datasets to gain a better understanding of this issue.

Insurer Hassles for Providers

Commenting on the findings, Ghazala Hayat, MD, a neurologist at Saint Louis University School of Medicine, St. Louis, who was not involved in the study, told Medscape Medical News that minimizing or discontinuing steroid use remains a central goal in gMG management. On that front, she said, efgartigimod is valuable, though many patients may require treatment indefinitely.

Hayat noted that obtaining insurance approval for efgartigimod can also be time-consuming. “Most insurance companies are improving, but it’s still an uphill task,” she said. She also pointed out that the need for frequent infusions can be challenging for patients who must take significant time off work. Subcutaneous efgartigimod will be a major step forward,” she added.

This study was funded by Argenx. Goyal disclosed relationships with Argenx, UCB Pharma, Amgen, Janssen, and Alexion. Several study authors reported being employees of Argenx. Other authors disclosed relationships with multiple pharmaceutical companies, as detailed in the published manuscript.

Hayat disclosed relationships with Argenx and Alexion.