GC012F Injection in Refractory Idiopathic Inflammatory Myopathy

This is a single-arm, open-label, early exploratory clinical study to evaluate the safety and efficacy of GC012F Injection in subjects with refractory idiopathic inflammatory myopathy and to assess the pharmacokinetic and pharmacodynamic profiles. This study consists of screening period, apheresis period, baseline period, lymphodepleting preconditioning period, pre-infusion evaluation period, CAR-T cell infusion period and follow-up period. Eligible subjects will undergo apheresis and receive infusion following the manufacture of the CAR-T product. Subjects will receive lymphodepleting preconditioning before CAR-T cell infusion and will be assessed before infusion. If the criteria for cell infusion are met, CAR-T cell infusion will be performed and the infusion dose in the same group or subsequent treatment groups may be adjusted according to the safety and clinical response. A total of 1 dose group will be set for CAR-T cell infusion dose in this study: 3 × 10\^5/kg. Approximately 12 subjects are planned to be enrolled. Subjects will be monitored for dose-limiting toxicity (DLT) within 28 days following the infusion of GC012F Injection. For the first 3 patients receiving infusions of GC012F, 3 additional patients will be included in this cohort if no more than 1/3 of the patients experience DLTs at a given dose level. If 2/3 or more DLTs occur at this dose level, a spare dose of 2.0 × 10\^5/kg or 1.0 × 10\^5/kg may be administered to subsequent subjects following discussion between the investigator and the partner. If no more than 1 out of the first 6 subjects experiences a DLT, 6 additional subjects will be enrolled. Once 2 subjects experience DLTs, the investigator and the partner will discuss and decide whether to use a spare dose group of 2.0×10\^5/kg or 1.0×10\^5/kg. After the first 3 subjects have all completed the 28-day DLT observation period, the Safety Monitoring Committee (SMC) will conduct an assessment based on clinical safety and pharmacokinetic data (if available). Subsequently, the SMC may, depending on the safety profile and study progress, request an increased frequency of safety committee assessments and reviews. After completing the DLT observation period for all subjects in this dose group, all clinical study data collected during the DLT observation period for this dose group, especially safety data, will be assessed, and whether to add new subjects to this dose group and whether to explore a different dose group will be decided upon discussion between the investigator and the partner. Following CAR-T cell infusion, subjects will be followed for safety, cell proliferation and survival, and efficacy until the subject withdraws from the study and refuses subsequent follow-up, or dies, or withdraws consent, or is lost to follow-up, whichever occurs first.