Soliris, Vyvgart effective in adults with generalized MG: Study
Soliris outperformed Vyvgart at reducing disease severity, corticosteroid dose
Both Soliris (eculizumab) and Vyvgart (efgartigimod alfa-fcab) rapidly eased disease severity among adults with generalized myasthenia gravis (gMG), according to a real-world study that compared the two therapies.
Soliris outperformed Vyvgart in its ability to reduce gMG severity and corticosteroid dose over a year of treatment, however. Details of the real-world analysis were reported in the study, “A real-life experience with eculizumab and efgartigimod in generalized myasthenia gravis patients,” in the Journal of Neurology.
MG is an autoimmune disease wherein self-reactive antibodies attack proteins involved in nerve-muscle communication, leading to symptoms of muscle weakness and fatigue. Some symptoms are limited to the muscles of the eyes and eyelids, where the disease is called ocular MG. When muscle weakness is more widespread and not restricted to a particular group, it’s called gMG.
Standard of care typically consists of treating symptoms with Mestinon (pyridostigmine bromide), immunomodulating therapies, such as corticosteroids, and a thymectomy, which is the surgical removal of the thymus gland. Many patients continue to have symptoms, however.
Soliris and Vyvgart are relatively new therapies approved for adults with gMG who test positive for self-reactive antibodies against the acetylcholine receptor (AChR), the most common type of MG-causing antibody. Both are administered via infusions into the vein, or intravenously.
The medications have two different mechanisms of action. Vyvgart promotes the breakdown of the antibodies, while Soliris blocks the complement cascade, a part of the immune system that contributes to the disease’s damaging immune response.
Comparing Soliris, Vyvgart in gMG
Here, researchers in Italy described real-life experiences with Soliris and Vyvgart in adults with gMG, and assessed the differences between the treatments.
“Our study is the first real-world report comparing the efficacy of two novel therapeutic approaches in gMG,” they wrote.
Of the 63 gMG patients studied, 32 were treated with Soliris and 31 with Vyvgart. Although Soliris-treated patients were older, both groups were comparable in gender, disease duration, and thymectomy before treatment, called the baseline. Nine Vyvgart-treated patients tested negative for antibodies against AChR.
The researchers collected baseline and follow-up data on two standardized assessment tools of MG severity: the MG-Activities of Daily Living (MG-ADL) and the Quantitative MG (QMG). MG-ADL is a patient-reported scale that assesses MG symptoms and their effects on daily activities. QMG is a physician-guided measure of disease severity.
Both therapies significantly reduced, or improved, MG-ADL scores. Significant effects were seen after a week of treatment and were sustained through week 48, about a year. Over time, changes in MG-ADL scores were similar between the two treatment groups.
Vyvgart had a comparable effect on patients with or without self-reactive antibodies targeting AChR. When only those with these antibodies were considered, Vyvgart had no significant impact on MG-ADL scores.
Both treatments significantly reduced, that is, improved, QMG scores, with significant effects starting after four weeks and maintained to week 48.
Soliris outperformed Vyvgart at reducing QMG scores from week 12 to week 48. Similar results were seen for patients with anti-AChR antibodies. Consistent with these findings, Soliris-treated patients were more likely to achieve a QMG response, that is, have a reduction in QMG scores of at least 3 points, than Vyvgart-treated patients.
Comparing MG complications
Researchers then compared the number of MG-related complications, such as clinical deterioration, myasthenic crisis, and hospitalizations, before and during treatment.
Among Soliris-treated patients, the mean number of events fell from 1.06 in the year before treatment to 0.09 during treatment, representing a 91.5% reduction. Those treated with Vyvgart also saw a drop in the mean number of complications, from 0.37 to 0.26, corresponding to a 29.7% reduction.
Soliris was consistently associated with a 55.7% lower chance of complications than Vyvgart, whose patients were more likely to stop treatment, mostly due to MG deterioration. Soliris also had a more favorable impact on reducing the dose of prednisone, an immunomodulating corticosteroid, than Vyvgart.
Both treatments were well tolerated. Of the three serious adverse events reported, none were deemed related to treatment.
“Our study provides evidence that [Soliris] and [Vyvgart] can be used in clinical practice to reduce disability in gMG patients,” wrote the researchers, who recommended “caution in interpreting the results of this study, as it is the first real-life follow-up and comparison of two novel approaches.”
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