Vyvgart® (efgartigimod) may be an efficient single-treatment option for myasthenia gravis (MG), according to a study recently published in Expert Review of Clinical Immunology.

“If their safety and tolerability are established, these drugs could improve the quality of life and mental health of MG patients by decreasing the social disadvantages presented by this disease,” the authors wrote.

This expert review discussed the latest data on immunotherapy and other treatment alternatives for patients with MG, focusing on the Japanese clinical guidelines for MG, released just a few months ago.

Read more about MG therapies

Currently, acetylcholinesterase inhibitors, such as neostigmine, ambenonium, and pyridostigmine, as well as immunomodulators, such as corticosteroids, constitute the main drugs for this neuromuscular disorder. Although beneficial for most patients, up to 20% of the cases of MG are refractory to conventional treatment, as noted by Suzuki and colleagues.

Thus, novel therapeutic approaches could greatly impact these patients. The authors widely explained the benefits and current status of efgartigimod. This drug directly blocks the neonatal fragment crystallizable (Fc) receptor immunoglobulin G (IgG) Fc fragment. It achieves an immunomodulatory effect by impairing neonatal Fc receptor binding to class I major histocompatibility complex-like receptors.

Efgartigimod has already undergone pre-clinical research and phase 2 and 3 trials. Results from ADAPT, a randomized, double-blind, placebo-control study, demonstrated promising results for this therapy. The majority of the participants (68%) achieved an increase in the Myasthenia Gravis-Activities of Daily Living score of 2 or more points after a single dose. In comparison, almost all (78%) patients obtained the same results after 2 doses. The symptomatic improvement continued for over 12 weeks in about a third of the cases.

Regarding safety, previous publications reported that the control and efgartigimod groups experienced adverse effects in 84% and 77% of the cases, respectively. The most common symptoms were headaches, followed by nasopharyngitis, nausea, diarrhea, upper respiratory tract infection, and urinary tract infection. Severe adverse reactions occurred in 11% of the patients treated with efgartigimod, including depression, thrombocytosis, rectal adenocarcinoma, and worsening of MG symptoms, which led to treatment discontinuation in all cases.

Although further studies need to confirm this drug’s effectiveness and safety, these preliminary results suggest that efgartigimod may yield benefits that previous drugs for MG have not achieved.

“The targeted depletion of IgGs by efgartigimod could provide a clear safety advantage over techniques such as plasma exchange, which removes all serum proteins and thus results in broader immunosuppression and increased risks of infection,” the study concluded.

Reference

Suzuki S, Uzawa A, Murai H. Efgartigimod for generalized myasthenia gravis with or without anti-acetylcholine receptor antibodies: a worldwide and Japanese perspective. Expert Rev Clin Immunol. Published online October 17, 2022. doi.org/10.1080/1744666X.2022.2136167