The following article is part of conference coverage from the American Academy of Neurology (AAN) 2021 Virtual Annual Meeting. Neurology Advisor’s staff will be reporting breaking news associated with research conducted by leading experts in neurology. Check back for the latest news from the AAN 2021 Virtual Annual Meeting.

Efgartigimod is an effective and well-tolerated treatment option for patients with myasthenia gravis (MG), according to study results presented at the American Academy of Neurology 2021 Virtual Annual Meeting, held April 17 to 22, 2021.

As there are limited effective and safe treatment options for MG, study researchers sought to assess the efficacy of efgartigimod, a human IgG1 antibody Fc-fragment that blocks FcRn and reduces IgG autoantibody.

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This 26-week, Phase 3, randomized, placebo-controlled trial included patients with generalized MG, most of whom had nonocular symptoms. The participants were randomly assigned to receive 4 weekly infusions of efgartigimod (10 mg/kg) or placebo. Response to treatment, the primary outcome of the study, was defined as an improvement of at least 2 points of MG-ADL score sustained for at least 4 weeks after first treatment cycle.

The study sample included 167 patients, including 129 patients with evidence for acetylcholine receptor antibodies and 38 patients without these antibodies.

According to MG-ADL score, approximately two thirds (67.7%) of patients with acetylcholine receptor antibodies responded to treatment with efgartigimod, compared with 29.7% of those in the placebo arm (P <.0001). Most of these patients (84.1%) responded to treatment within the first 2 weeks.

According to Quantitative Myasthenia Gravis score, 63.1% of treated patients with acetylcholine receptor antibodies, compared with 14.1% patients in the placebo arm, responded to first treatment cycle. Most of these patients (82.9%) responded to treatment within the first 2 weeks.

The efficacy of efgartigimod was similar in patients who had never received nonsteroidal immunosuppresants and in those previously treated with these agents.

Among patients without acetylcholine receptor antibodies, response rates according to both MG-ADL and Quantitative Myasthenia Gravis scores were 47.4% for efgartigimod, compared with 21.1% with placebo.

Most adverse events were mild or moderate with few of at least grade 3 severity.

“Efgartigimod demonstrated significant efficacy in treating patients with MG and was well tolerated” in this population, concluded the study researchers.


Howard J, Bril V, Vu T, et al. Efficacy, safety, and tolerability of efgartigimod in patients with generalized myasthenia gravis: analysis of the phase 3 ADAPT study. Neurology. Presented at the American Academy of Neurology 2021 Virtual Annual Meeting; April 17-22, 2021.