Real-life experience using Efgartigimod in Myasthenia Gravis patients: Alternative frequency of administration based on individual patient response


Clinical Management

Poster Number: M228


Stephanie Iyer, PharmD, CPP, BCACP, UNC Health, Andriana Tompary, DO, University of North Carolina - Chapel Hill, Said Alhassan, BS, UNC Neuroscience Clinical Trials Unit, Anahit Mehrabyan, MD, University of North Carolina

Background: Efgartigimod is the first FcRn inhibitor that has been approved for the treatment of generalized Myasthenia Gravis (MG). In ADPT trial Efgartigimod was prescribed as a weekly infusion in cycles of 4 with at least 4-week interval with adjustment of the frequency of cycles based on the individual patient’s response. There is limited information regarding the real-life experience of alternative mode of Efgartigimod administration.

Methods: Medical records of 28 patients with a diagnosis of MG, who have been treated from January 2022 to September 2023 with efgartigimod were reviewed. 17 (60%) continued the treatment and 11 (39%) discontinued mainly due to lack of response to treatment. 8 male and 9 female with average age of 56 years (25-82 years) and 11.5 years of average duration of MG diagnosis continued the treatment. 15 were AChR positive, 1 MuSK positive, 1 seronegative; all have been on treatment with steroids or steroid sparing agents; average MG ADL score was 5.9 (range 1-13).

Findings: All patients had an initial cycle of 4 weekly infusions. Of the 17 patients 3 (17%) continued cycles of 4 weekly infusions with 4-week intervals in between. The frequency of infusions was modified in majority of patients based on the clinical response and side effects. A cycle of 2 weekly infusions with 2-week intervals was the most common mode of treatment (8 patients-47%). The remaining 6 patients had other various frequencies. Most common side effects reported were mild infections, headache, and nausea. A total of 10 patients (59%) had more than 3-point improvement on MG-ADL score.

Conclusion: We report a real-life experience of MG patients treated with efgartigimod, where alternative to clinical trial intervals were used. The most common mode of administration in our patients’ population was a cycle of 2 weekly infusions with 2-week intervals.