Effectiveness and Safety of IVIG for the Treatment of HMGCR Immune‐Mediated Necrotizing Myopathy
Year: 2024
Type: article
Study design: Observational Study
Abstract: INTRODUCTION/AIMS: Immune-mediated necrotizing myopathy (IMNM) is an autoimmune myopathy. We aimed to compare clinical outcomes in patients with antibodies against 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) treated on immunotherapy regimens with and without maintenance intravenous immunoglobulin (IVIG). The secondary aim was to assess outcomes in a subset that received IVIG monotherapy. METHODS: This was a retrospective longitudinal cohort study. Multivariate logistic regression was used to analyze the association between IVIG and the probability of reaching normal creatine kinase (CK) and normal/near-normal proximal muscle strength at 3- and 6-month follow-ups. In patients treated with IVIG monotherapy, changes in CK and strength were analyzed using Wilcoxon signed rank tests. RESULTS: Patients treated with IVIG (n = 40) had higher odds of CK normalization at 6 months (OR 9.44, 95% CI 1.19-74.89, p = 0.03) although not at 3 months (p = 0.08) compared to patients not treated with IVIG (n = 13). Increased odds of normal/near-normal proximal muscle strength was not observed at 3 months (p = 0.14) or 6 months (p = 0.35). Subgroup analysis of patients on IVIG monotherapy (n = 15) showed a median CK reduction of 84.5% at 3 months (p < 0.001) and 95.7% at 6 months (p < 0.001). CK normalized in 40% by 6 months. Proximal muscle strength improved at 3 months (p = 0.003) and 6 months (p = 0.008). 76.9% had normal/near-normal proximal strength by 6 months. DISCUSSION: Patients treated with immunotherapy regimens that included IVIG were more likely to reach normal CK at 6 months. Maintenance IVIG monotherapy also induced marked improvements in CK and strength. IVIG monotherapy can be an effective first-line treatment for HMGCR IMNM.
Source: Muscle & Nerve
DOI: 10.1002/mus.28333
Authors: Joome Suh, Anthony A. Amato
Institutions: Brigham and Women's Hospital, Harvard University
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4405854037