Vyvgart may offer IVIG alternative for people with hard-to-control gMG

Switching from intravenous immunoglobulin (IVIG) to Vyvgart (efgartigimod alfa) was associated with fewer hospitalizations and better quality-of-life scores after the switch in people with generalized myasthenia gravis (gMG), according to a study in Japan.

Also, a greater proportion of patients transitioning to Vyvgart achieved minimal manifestations, a status marked by no MG symptoms or functional limitations, relative to those who continued on IVIG. However, group differences failed to reach statistical significance. This suggested that Vyvgart may offer effectiveness comparable to IVIG, although the researchers said the findings should be interpreted with caution given the study’s small size and retrospective observational design.

Overall, these findings indicate that Vyvgart may be a “suitable option for patients who exhibit insufficient response to conventional [fast-acting therapies like IVIG] or who are unable to continue [such therapies] due to adverse effects,” the researchers wrote.

The study, “Clinical and quality-of-life outcomes associated with efgartigimod in patients with generalized myasthenia gravis transitioning from intravenous immunoglobulin,” was published in Clinical Neurology and Neurosurgery.

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Vyvgart works by lowering MG-driving antibodies

Myasthenia gravis (MG) is an autoimmune disease usually caused by self-reactive antibodies that target proteins involved in nerve-muscle communication. In gMG, muscle weakness is not limited to the muscles around the eyes.

Therapeutic strategies aim to control symptoms while minimizing exposure to oral corticosteroids, a type of anti-inflammatory and immunosuppressive treatment that may cause serious side effects with long-term use.

Fast-acting treatments, such as IVIG, are commonly used to treat MG exacerbations, which are sudden worsenings of symptoms. IVIG contains pooled antibodies from healthy donors that can help neutralize or reduce the production of harmful antibodies, including those driving MG.

Vyvgart is an approved gMG therapy that works by blocking a protein that prevents the destruction of circulating antibodies, thereby decreasing the levels of MG-driving antibodies. The therapy may be given through weekly into-the-vein infusions, or as under-the-skin injections with Vyvgart Hytrulo, in four-week cycles.

In Japan, the therapy “is indicated for patients with g-MG whose symptoms are difficult to manage with [fast-acting therapies] or who cannot receive [such therapies] due to adverse effects,” the researchers wrote. “Additionally, patients for whom hospitalization is not feasible for social or financial reasons are suitable candidates for outpatient [Vyvgart] treatment.”

To assess whether switching from IVIG to Vyvgart might be a safe and effective therapeutic strategy in people with gMG, a team of researchers in Japan analyzed data from 67 gMG patients who received IVIG at their hospital between May 2022 and March 2024. All were on either oral corticosteroids or other oral immunosuppressive treatments, but required fast-acting therapies due to inadequate symptom control.

Study looked at outcomes after switching from IVIG to Vyvgart

A total of 55 patients received IVIG as rescue therapy during exacerbations over the study period (IVIG group), while 12 had been treated with IVIG but subsequently initiated Vyvgart, given by into-the-vein infusion and/or under-the-skin injection (switch group). Patients in the switch group occasionally received IVIG or other fast-acting therapies, including intravenous corticosteroids, to manage exacerbations.

Participants had a mean age of 62.9 years, 65% were women, and they had a mean disease duration of about nine years. Those in the switch group were significantly younger, and the group had a significantly higher proportion of women.

The switch group tended to have more severe disease, according to the Myasthenia Gravis Foundation of America (MGFA) classification system, and received IVIG and intravenous corticosteroids more often. This suggests that the switch group “experienced a more severe disease course,” the researchers wrote.

After treatment started, a greater proportion of patients in the switch group achieved minimal manifestations than in the IVIG group (33% vs. 15%). A greater proportion also achieved minimal manifestations while taking a low corticosteroid dose of 5 mg or less relative to the IVIG group (17% vs. 7%). However, these group differences failed to reach statistical significance, meaning they could be due to chance.

The proportion of patients rated as improved or better increased from 13% before treatment to 86% after treatment in the IVIG group, and from 17% to 67% in the switch group.

These results show that people with treatment-resistant gMG “who switched to outpatient [Vyvgart] therapy after an adequate response to IVIG achieved treatment outcomes comparable to those who continued IVIG,” the team wrote.

Hospital stays fell after patients switched to Vyvgart

While the total number of hospitalizations was significantly higher in the switch group relative to the IVIG group, the number of hospitalizations fell significantly within the switch group, from 2.6 in the year before Vyvgart was started to 1.1 in the year after treatment began. Quality of life, assessed with the Japanese version of the Myasthenia Gravis Quality of Life 15-Item Scale-Revised, also improved significantly after patients switched to Vyvgart.

In a questionnaire survey administered to 10 participants who received Vyvgart, most reported greater benefit after starting the treatment, particularly in their ability to fulfill roles at home, take part in work and social activities, and enjoy hobbies and entertainment. Nine of the 10 patients said they preferred Vyvgart over IVIG. Reasons included less impact on housework and family, a preference for a home environment, less impact on work, fewer activity restrictions, and IVIG-related side effects.

Adverse events during treatment were reported by 31% of patients in the IVIG group and 50% of those in the switch group. In both groups, the most common were headache and gastrointestinal issues.

Vyvgart “may provide therapeutic efficacy comparable to or greater than that of IVIG,” and “may be a valuable outpatient treatment option for [treatment-resistant] MG,” the researchers wrote.