Abstract Details

Title Use of Efgartigimod in Treatment of Myasthenia Gravis Relapse after Possible Recurrence of Invasive Thymoma: A Case Report.

Topic Autoimmune Neurology

Presentation(s) P1 - Poster Session 1 (8:00 AM-9:00 AM)

Poster/Presentation
Number 6-011

Objective NA

Background Myasthenia gravis is an autoimmune neuromuscular junction disorder with established association with thymoma. There is no consensus on optimal treatment of recurrent thymoma post-resection. Efgartigimod is a first-in-class FcRn antagonist approved by the FDA in December 2021 for treatment of AChR-antibody-positive adults with generalized MG.

Design/Methods NA

Results A 53-year-old right-handed man presented to us in September 2020 with a 10-month history of recurrent diplopia, ptosis, dysarthria, dysphagia, and bilateral hand weakness. Workup for MG revealed blocking, binding, and modulating AChR antibodies. CT scan of his chest demonstrated an invasive anterior mediastinal mass. He started pyridostigmine, mycophenolate and prednisone, and underwent a sternotomy with thymectomy with sparing of the directly adjacent right phrenic nerve in October 2020. Histopathology revealed a locally invasive Masaoka stage IIIA, pT1bN0M0, WHO type B2 thymoma. He received adjuvant radiotherapy until January 2021. He was weaned off prednisone and pyridostigmine by May 2021. He remained asymptomatic for about 18 months post-thymectomy except for transient dysarthria in September 2021 attributed to missed mycophenolate doses.
Patient noticed recrudescence of bulbar and respiratory symptoms around April 2022. Tests showed elevated AChR antibodies but surveillance chest CT scans did not demonstrate tumor recurrence or metastases. His cardiothoracic surgeon remained suspicious of residual thymoma. He started efgartigimod in July 2022 which he tolerated well, resulting in symptom resolution and objective improvement on MG-specific outcome measures (MG-ADL, MG-QoL15r and MGC). His symptoms recurred during a COVID-19 infection a month later, but he rapidly became asymptomatic after completing the second efgartigimod cycle in September 2022.

Conclusions Our patient with AChR antibody-positive, thymoma-associated, generalized MG with recurrent symptoms despite mycophenolate treatment, thymectomy and radiotherapy showed a dramatic response to initial cycles of efgartigimod therapy without significant adverse effects. We propose that efgartigimod be considered early in the management of MG patients with recurrent symptoms after thymectomy.

Authors/Disclosures
Elif P. Coskun, MD (work) PRESENTER	Dr. Coskun has nothing to disclose.
Fatai M. Akemokwe, MBBS	Dr. Akemokwe has stock in CVS HEALTH CORP. Dr. Akemokwe has stock in LABORATORY CORP AMERICAN HOLDINGS.
	No disclosure on file
	No disclosure on file
Ima M. Ebong, MD, FAAN (University of Kentucky)	The institution of Dr. Ebong has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB. The institution of Dr. Ebong has received research support from Ad Scientiam.

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