Statin-induced Anti-HMGCR Immune-mediated Necrotizing Myopathy

Statin-induced Anti-HMGCR Immune-mediated Necrotizing Myopathy

Statin-induced anti-HMGCR immune-mediated necrotizing myopathy (IMNM) is a rare but serious autoimmune condition. It typically presents with progressive proximal muscle weakness and markedly elevated creatine kinase (CK) levels and persists if statin therapy is discontinued. The disease can develop months to years after statin initiation and is often associated with anti-HMGCR antibodies. Risk factors include an age of more than 50 years, the presence of the HLA-DRB1*11 allele and concomitant malignancy. Management requires immunosuppressive therapy, which commonly involves corticosteroids in combination with agents such as methotrexate, azathioprine, intravenous immunoglobulin (IVIG) or rituximab. Early diagnosis and timely initiation of treatment are critical to optimizing motor recovery and preventing disease progression. Patients who require continued lipid-lowering therapy are prescribed non-statin alternatives, such as proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors or ezetimibe.