To report cases where alternative dosing of efgartigimod in generalized myasthenia gravis was more effective than the traditional dosing pattern.
Efgartigimod is a neonatal Fc receptor blocker approved for the treatment of generalized myasthenia gravis with treatment dosing typically consisting of cycles of weekly IV infusions for 4 weeks with the next cycle not occurring until 8 weeks following initiation of previous cycle. Alternative dosing strategies allow for more flexibility and improved outcomes in certain patients.
2 patients, a 38 year old female and a 44 year old male both with antibody positive, generalized myasthenia gravis were treated with efgartigimod however had recurrence of symptoms as early as 1 week following last infusion. Dosing schedule was switched to every other week infusions with improvement in symptoms.
A 3rd patient, a 61 year old male with antibody positive, generalized myasthenia gravis was treated with efgartigimod however would have recurrence of symptoms 2 weeks following last infusion. His dosing schedule was switched to infusions once weekly for 4 weeks with only 2 weeks off with improvement in symptoms control.
Efgartigimod is a part of a newer class of treatments for myasthenia gravis targeting the neonatal Fc receptor resulting in decreased circulating immunoglobulin levels. Dosing of efgartigimod is typically weekly infusions for 4 weeks and then an “off” period of 4 weeks. Unfortunately, some patients have recurrence of their myasthenic symptoms during the “off” period. These cases support that alternative dosing of efgartigimod is effective in certain patients with early recurrence of symptoms.