A Phase I/II Study of Eque-cel in Subjects Withimmune-mediated Necrotizing Myopathy

Inclusion Criteria: * 1\. At the time of signing the informed consent form, the age is ≥ 18 years old. * 2.Based on the 2016 ENMC classification criteria, the clinical diagnosis is IMNM. * 3.At the time of screening, the anti-SRP antibody or anti-HMGCR antibody is positive. * 4\. Refractory IMNM that failed or relapsed after standard treatment, and the disease is still active at the time of screening. * 5.The subjects must have appropriate organ functions. * 6.The subjects and their spouses agree to take effective contraceptive measures (excluding safe period contraception) from the time of the subject signing the informed consent form until one year after the CAR-T cell infusion. * 7\. The subjects must agree to sign or personally write and present the informed consent form approved by the ethics committee before starting any screening procedures. Exclusion Criteria: * 1\. Having end-stage myositis with involvement of terminal organs may pose additional risks or interfere with the study assessment. * 2.Presence of irreversible muscle involvement and/or severe atrophy may bring additional risks or interfere with the study assessment. * 3.Uncontrolled interstitial lung disease or any other uncontrolled manifestations of IIM, as judged by the investigator, may require the use of prohibited drugs during the study period. * 4\. Diagnosed with other inflammatory or non-inflammatory myopathies. * 5.Any other known autoimmune disease that the investigator considers to interfere with the accurate assessment of clinical symptoms of IMNM or place the patient at excessive risk. * 6\. Those with a history of solid organ transplantation. * 7\. History of autologous or allogeneic stem cell transplantation. * 8\. Previous history of BCMA-targeted drug treatment. * 9.Having occurred or planned to undergo major surgery or surgical treatment within 4 weeks before enrollment or within 12 weeks after infusion. * 10\. Known primary immunodeficiency (congenital or acquired). * 11\. Having a clear history of mental disorder or a history of substance abuse for mental disorders that cannot be quit. * 12.The subject has uncontrollable active fungal， viral， bacterial or other infections (having persistent infection-related signs/symptoms， without improvement after appropriate anti-infection treatment) or infections requiring intravenous anti-infection drug treatment. * 13.Positive hepatitis B surface antigen (HBsAg) or hepatitis B core antibody (HBcAb) and abnormal peripheral blood hepatitis B virus (HBV) DNA test (defined as HBV DNA quantification ≥ 100IU/ml or ≥ 1000 copies /ml or above the normal reference range of the testing center or positive for qualitative HBV DNA detection) ; hepatitis C virus (HCV) antibody positive and peripheral blood HCV RNA positive (defined as ≥ 1000 IU/mL); human immunodeficiency virus (HIV) antibody positive; cytomegalovirus (CMV) DNA positive (defined as ≥ 1000 IU/mL); Treponema pallidum specific antibody positive and positive for the rapid plasma reagin test for syphilis. * 14.Severe heart disease: including but not limited to unstable angina pectoris and/or myocardial infarction within 12 months of the screening period, any congestive heart failure (NYHA classification ≥ III), and a history of severe arrhythmia. * 15.Severe asthma or chronic obstructive pulmonary disease (COPD). Note: Mild or moderate asthma or COPD patients with stable conditions, after assessment and approval by the investigator and the sponsor, can be enrolled. * 16.Acute cerebrovascular disease events occurred within 6 months before enrollment, including transient ischemic attack or stroke history. * 17.Any serious and/or uncontrolled comorbid diseases as determined by the investigator to potentially interfere with the study assessment. * 18.Malignant tumors within 5 years before screening, excluding cured cervical carcinoma in situ, basal cell or squamous epithelial cell skin cancer, locally advanced prostate cancer after radical surgery, breast duct carcinoma in situ after radical surgery, or thyroid papillary carcinoma after radical surgery. * 19\. Known history of allergy to cyclophosphamide, fludarabine, components of Eque-cel injection or supportive drugs required for toxicity management of CAR-T cell therapy (such as tocilizumab). * 21.Pregnant or lactating women. * 21\. Other situations as determined by the investigator to be unsuitable for enrollment.