Inclusion Criteria:
* Age ≥ 18 years and ≤ 70 years.
* Patient has a confirmed diagnosis of inflammatory myopathy, meeting the 2017 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for idiopathic inflammatory myopathies.
* Inadequate response or intolerance to glucocorticoids and/or at least one immunosuppressant.
* The patient or their legal guardian provides written informed consent.
Exclusion Criteria:
* Female patients who are pregnant, breastfeeding, or planning a pregnancy during the trial period.
* Patients with active infections, such as herpes zoster, HIV, active tuberculosis, active hepatitis, HBsAg-positive patients, or HCV antibody-positive patients.
* Patients with positive test results indicating COVID-19 infection within 1 month prior to baseline.
* Patients with a history of or currently diagnosed malignancy.
* Patients with significant cardiovascular diseases (including severe arrhythmia), hepatic, renal, respiratory, endocrine, or hematological disorders, or any other medical condition that, in the investigator's judgment, would interfere with participation in the study or require hospitalization during the trial.
* Patients who have received intravenous immunoglobulin (IVIG) or plasmapheresis within 1 month prior to baseline.
* Patients who have received other targeted biologic therapies, such as rituximab, eculizumab, tocilizumab, etc., within 3 months prior to baseline.
* Patients who have received any live vaccine within 3 months prior to baseline or plan to receive any vaccine during the study period.
* Patients with a known allergy to human-derived biologics.
* Patients currently participating in another clinical trial.
* Patients deemed unsuitable for participation by the investigator for other reasons (e.g., severe psychiatric disorders).
