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Background: Immune-mediated necrotizing myopathy (IMNM) is a rapidly progressing autoimmune muscle disease that severely affects the proximal, respiratory, and cardiac muscles. There is no globally unified consensus on treatment. Here, we compare the effects of cyclophosphamide (CTX) and methotrexate (MTX) in IMNM to provide evidence for treatment strategies. Methods: This is a retrospective single-center study. Patients were assigned into a CTX group or an MTX group based on the type of immunosuppressant. Statistical analyses were compared using SPSS 23.0. Results: A total of 35 patients were included— 19 in the CTX group, and 16 in the MTX group. Before treatment, the aspartic transaminase (AST) levels were significantly higher in the CTX group than in the MTX group (P < 0.05). All patients received high-dose glucocorticoids as basic therapy. After inductive treatments, the proportion of patients whose creatine kinase (CK) decreased by more than 50% was higher in the CTX group (18 cases, 94.7%) than in the MTX group (10 cases, 62.5%; P < 0.05). The descent degree of laboratory indicators were analyzed further. Reductions in CK (6919.1 U/L vs. 3245.3 U/L), lactate dehydrogenase (LDH, 964.0 U/L vs. 318.5 U/L), and AST (225 U/L vs. 52.5 U/L) were also greater in the CTX group than in the MTX group (P < 0.05). Conclusion: In this cohort of IMNM patients, CTX achieved greater improvements in CK, LDH, and AST levels compared to MTX. CTX may be more beneficial than MTX for disease inductive treatment in IMNM patients. This finding provides evidence for selecting clinical treatment schemes. Keywords: immune-mediated necrotizing myopathy, cyclophosphamide, methotrexate
Li et al. (Mon,) studied this question.