Abstract Details

Title Rapid Clinical Improvement of Anti-HMGCR Immune-mediated Necrotizing Myopathy (IMNM) Treated with Efgartigimod

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) P3 - Poster Session 3 (11:45 AM-12:45 PM)

Poster/Presentation
Number 11-015

Objective NA

Background Immune-mediated necrotizing myopathy (IMNM) with anti-HMGCR antibody positivity is characterized by proximal extremity weakness, increased creatine kinase, and extensive muscle edema. There is an urgent need to find more appropriate treatment options for anti-HMGCR IMNM patients who do not respond well to conventional therapy in the acute phase. With the advent of targeted biologics, new treatment options are available.

Design/Methods NA

Results We report on a 66-year-old anti-HMGCR IMNM patient who initially presented with a 1-month history of progressive proximal extremity weakness (Manual Muscle Testing-8 [MMT8]: 63 out of 80; Water Swallow Test: grade 2) and dysphagia with markedly elevated creatine kinase. The patient did not respond to conventional high-dose glucocorticoid and intravenous immunoglobulin therapy, and his symptoms rapidly deteriorated over the 2 weeks after this treatment (MMT8: 48 out of 80; Water Swallow Test: grade 4), with worsening limb weakness that prevented walking, marked proximal muscle atrophy, and weight loss. After one cycle (four infusions) of efgartigimod, the patient’s symptoms improved markedly (MMT8: 74 out of 80, Water Swallow Test: grade 1) and he has since (for several months) remained in a good clinical state.

Conclusions There are no previous studies or case reports on the use of efgartigimod in patients with anti-HMGCR IMNM, and our case provides some limited experience in this regard.

Authors/Disclosures
Quantao Zeng PRESENTER	Quantao Zeng has nothing to disclose.
Kai Chen, PhD (Simcere of America, Inc)	No disclosure on file
Li Zeng (Sichuan Provincial People’s Hospital)	No disclosure on file
Lixia Xu (Sichuan Provincial People’s Hospital)	No disclosure on file
Song Tan	No disclosure on file

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