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INTRODUCTION/AIMS: Efgartigimod, a neonatal Fc-receptor inhibitor, has recently been approved as treatment for myasthenia gravis (MG). In this retrospective cohort study, we aimed to systematically assess short- and long-term effectiveness of efgartigimod in patients with refractory MG. METHODS: Sixteen patients with refractory autoimmune acetylcholine receptor MG were treated with efgartigimod. Data were collected from January 2021 to March 2023 on Myasthenia Gravis Activities of Daily Living (MG-ADL), Quantitative Myasthenia Gravis score (QMG), Myasthenia Gravis Composite score (MGC) and the 15-item revised version of the Myasthenia Gravis Quality of Life questionnaire (MG-QoL15r). RESULTS: A favorable outcome was seen in 56% of patients at the last measurement. Out of 16 patients, 50% were an MG-ADL responder after the first treatment cycle. After 4 weeks, a clinically meaningful improvement compared to baseline was seen on the MG-ADL, QMG, and MGC. There was a statistically significant improvement on the MGQoL15r from baseline to week 4. The improvement was maintained until the last measurement for the MGC and the MGQoL15r. At the last visit, all patients had discontinued 4-weekly dosages, shifting to administration frequencies of 1, 2, or 3 weeks. Drug doses could be decreased for prednisolone (n = 7), azathioprine (n = 2), and intravenous immunoglobulin (n = 9). Frequency of plasma exchange was decreased in nine patients. DISCUSSION: In patients with refractory MG, efgartigimod was effective for at least half of all patients. Patients required more frequent dosing compared to the ADAPT phase 3 trial. In 80% of the patients concurrent medication could be reduced or discontinued.
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Pyridostigmine is the most commonly used drug in the symptomatic treatment of myasthenia gravis (MG); however, research into its effectiveness and side effects is scarce. The aim of this study was to assess the effectiveness, prevalence of side effects and net benefit of pyridostigmine. All MG patients participating in the Dutch-Belgian myasthenia patient registry were included. A dynamic online questionnaire was developed to assess the effectiveness, side effects and net benefit of pyridostigmine. Out of 642 invited patients, 410 patients (64%) fully completed the questionnaire; 61% reported that they currently used pyridostigmine, 36% had discontinued pyridostigmine and 2% reported to never have used pyridostigmine. Patients reported a median effectiveness of 60, IQR 28-78 and net benefit of 65, IQR 45-84. Of all patients currently using pyridostigmine, 91% reported side effects (vs. 55% in the control group). Most frequently reported side effects were flatulence, urinary urgency, muscle cramps, blurred vision and hyperhidrosis. In the group of patients who discontinued pyridostigmine, side effects were the reason for discontinuation in 26%. Diarrhea, abdominal cramps and muscle twitching were the most frequently cited reasons to discontinue pyridostigmine. These results can be used to guide shared decision making prior to starting symptomatic treatment for MG.