Myasthenia Gravis Patients May Use Less Steroids After Starting Efgartigimod

SAVANNAH, Ga. — One year after starting efgartigimod (Vyvgart) treatment, most generalized myasthenia gravis (gMG) patients significantly reduced corticosteroid use, claims data showed.

At 1 year, more than half (55%) lowered glucocorticoid usage by at least 5 mg/day on average, said Neelam Goyal, MD, of Stanford Medicine in Palo Alto, California, and co-authors at the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM) annual meeting.

Overall, 42% of gMG patients on efgartigimod achieved a glucocorticoid average daily dose of 5 mg/day or less at 1 year, and 62% achieved a glucocorticoid average daily dose of 10 mg/day, Goyal and co-authors reported in a poster presentation at the Myasthenia Gravis Foundation of America scientific session at AANEM.

By 1 year after efgartigimod initiation, 26% of patients were free of glucocorticoid use.

“Consistent with results observed previously at 6-months post-efgartigimod initiation, glucocorticoid usage continued to reduce significantly over 1-year post-efgartigimod initiation from baseline, while retaining expected MG-ADL [Myasthenia Gravis-Activities of Daily Living] response,” Goyal and colleagues noted.

“Glucocorticoids are a mainstay therapy in the management of many autoimmune conditions including gMG but are known to be associated with dose- and duration-dependent toxicities,” they pointed out. Published case reviews have suggested that glucocorticoid use may be lower with efgartigimod, they added, and there’s clinical interest in learning whether new gMG treatments can be used as steroid-sparing agents.

Reducing steroid burden is in and of itself a great benefit to patients suffering from autoimmune diseases, observed Luc Truyen, MD, PhD, chief medical officer of argenx, the company that makes efgartigimod.

“These retrospective data point to the potential for significant reduction of steroid usage in most Vyvgart patients, even up to the ability to stop steroids entirely in one out of four patients,” Truyen told MedPage Today. “We will further evaluate this, both through real-world evidence and prospective data collection.”

Efgartigimod was approved to treat gMG patients who test positive for the anti-acetylcholine receptor (AChR) antibody in 2021. The drug binds to the neonatal Fc receptor (FcRn) and prevents FcRn from recycling immunoglobulin G (IgG) back into the blood. It causes a reduction in circulating levels of IgG, including the abnormal AChR antibodies that are present in myasthenia gravis.

Goyal and co-authors used U.S. medical and pharmacy claims data from IQVIA to evaluate adult gMG patients with a first efgartigimod claim in 2022 and at least 1 year of efgartigimod treatment. All had evidence of chronic glucocorticoid use in the year before they started efgartigimod, and had no eculizumab (Soliris), rituximab (Rituxan), or ravulizumab (Ultomiris) treatment during the observation period.

More than half (54.3%) had commercial insurance for their first efgartigimod claim, and 42.1% had Medicare.

The researchers obtained MG-ADL scores for some participants through My VYVGART Path, a patient support program, which were tokenized and integrated with the primary dataset.

Overall, 164 gMG patients were included in the analysis. Median age was 62 and 46.3% were women. Nearly 80% had been exposed to non-steroidal immunosuppressive treatments or other advanced gMG therapies concomitantly with glucocorticoids in the year before they began efgartigimod treatment.

At baseline, mean glucocorticoid use was 17.2 mg/day. Three months after starting efgartigimod, it was 14.9 mg/day (PP

A subset of 71 participants had baseline and at least one MG-ADL score available within a year of starting efgartigimod. Their MG-ADL responses were consistent with what was expected with efgartigimod treatment, the researchers noted. “The extent of tapering among the subset was comparable to that observed overall,” they added.

Claims-based analyses are subject to potential coding errors, possible missing data, and assumptions, Goyal and co-authors acknowledged. In this study, estimated glucocorticoid usage was based on prescriptions only, they noted, and some tapering strategies may need to be explored with other alternative datasets.

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