Exploratory Clinical Study of TCR-T for MAGE-A4-positive Mesenchymal Malignancies

Inclusion Criteria: 1. Voluntarily sign a written informed consent form; 2. Gender is not limited. Age range: 18 to 75 years old (including the critical value). 3. Has histopathologically confirmed advanced mesenchymal malignancies, including but not limited to malignant phyllodes tumors of the breast, soft tissue sarcomas, osteosarcomas, etc. Has recurrent tumors, metastatic tumors or locally advanced tumors that have progressed after treatment and cannot be surgically resected, and has failed or cannot tolerate at least one line of standard treatment. 4. Has at least one measurable lesion (per RECIST1.1); 5. The H-score of MAGE-A4 expression in the patient's tumor tissue detected by immunohistochemistry reached 30 points or above. H-score = 1×(percentage of weakly positive cells) + 2×(percentage of moderately positive cells) + 3×(percentage of strongly positive cells), with a score range of 0 to 300. 6. HLA-A\*02 positive, except for the following situations: ① HLA-A\*02:05 in either allele; Or either HLA-A\*02 allele having the same antigen-binding domain as HLA-A\*02:05; ②HLA-A\*02:07 (or the HLA-A\*02 allele having the same antigen-binding domain as HLA-A\*02:07) or any A\*02 null allele as the sole HLA-A\*02 allele. For example, subjects containing both HLA\*02:01 and HLA\*02:07 meet this inclusion criterion. 7. Eastern Cooperative Oncology Group (ECOG) of 0 or 1; 8. Expected survival time ≥3 months; 9. Has the ability to collect peripheral blood for the preparation of TCR-T; 10. Absolute neutrophil count ≥ 1×10\^9/L; 11. Platelet count ≥50×10\^9/L, hemoglobin \>90g/dL; 12. Absolute lymphocyte count ≥0.5×10\^9/L; 13. Demonstrate adequate normal organ function: 1. Alanine aminotransferase ≤ 2.5× ULN (upper limit of normal value); 2. Aspartate aminotransferase ≤ 2.5× ULN; 3. Creatinine clearance rate ≥ 60 mL/min; 4. Serum total bilirubin ≤ 1.5× ULN; 5. Echocardiography diagnosed that the left ventricular ejection fraction (LVEF) of the subjects was ≥50% and no clinically significant pericardial effusion was observed. 6. No clinically significant electrocardiogram abnormalities were observed; 7. In the indoor natural air environment, the basic oxygen saturation exceeds 95%. 14. Women of childbearing age must have negative pregnancy results in blood human chorionic gonadotropin (HCG) (immunofluorescence method) during the screening period and baseline period, and agree to take effective contraceptive measures for at least one year after infusion; Male patients whose partners are women of childbearing age must agree to use effective barrier contraception for at least one year after infusion and avoid sperm donation. Contraceptive methods must include one highly effective and one additional effective (barrier) contraceptive method, which should be used from the start of screening until at least one year after TCR-T cell infusion or until two consecutive flow cytometry tests show that TCR-T cells are no longer present (whichever occurs later). 15. Has a specified washout period from prior anti-tumor therapies to peripheral blood collection for TCR-T preparation and before lymphodepleting chemotherapy: 1) anti-angiogenic drugs: 4 weeks; 2) chemotherapy and targeted therapy: 3 weeks; 3) radiotherapy: 2 weeks; 4) endocrine therapy: 1 week. Have recovered from prior therapy-related adverse events to Grade≤1 per CTCAE version 5.0 criteria or met the criteria of normal organ function specified above, except for second-degree peripheral nerve injury, alopecia, leukoderma, hypothyroidism controlled by thyroid hormone replacement therapy, type 1 diabetes controlled by insulin therapy, and other irreversible toxic events that would not be exacerbated by TCR-T infusion as judged by the investigator (e.g., hearing loss). Exclusion Criteria: 1. Suffering from other malignant tumors (excluding non-melanoma skin cancer that is disease-free for more than 5 years, cervical cancer in situ, bladder cancer in situ and breast cancer in situ that have undergone surgical treatment and show no signs of recurrence); 2. Has a history of mental disorders that may affect compliance with this plan or prevent the signing of the informed consent form; 3. Has poorly controlled hypertension (systolic blood pressure \>160 mmHg and/or diastolic blood pressure \>90 mmHg), or has suffered from grade III-IV heart failure or myocardial infarction, cardiac angioplasty or stent implantation, unstable angina pectoris, or other heart diseases with prominent clinical symptoms within one year prior to signing the informed consent form, or exhibits the QTc interval for males greater than 450 ms, and for females greater than 470 ms (the QTc interval is calculated using the Fridericia formula) during screening. 4. Has known active CNS metastases and/or carcinomatous meningitis except for previously treated and radiographically stable CNS metastases, or CNS metastase without medication requirement and corticosteroid dependence. To demonstrate radiographic stability of brain metastases, a minimum of 2 post-treatment brain imaging assessments are required: (1) The first brain imaging must be acquired after treatment of brain metastases has been completed; (2) The second brain imaging must be obtained during screening and 4 weeks after the previous post-treatment brain imaging. 5. Any of the following virological test results is positive: 1. Human immunodeficiency virus antibody (HIV antibody); 2. Patients that are hepatitis B surface antigen (HBsAg) or hepatitis B core antigen (HBcAg) positive may participate provided that the HBV DNA level is normal. Participants that are hepatitis C antibody positive may participate provided that the HBV DNA level is normal. Participants that are hepatitis C antibody positive may receive anti-virus therapy, and take regular DNA copy number tests during this trial. 3. Treponema pallidum antibody (TP antibody). If necessary, additional tests can be conducted to rule out active syphilis before enrollment. 6. Has fungal, bacterial, viral or other infections that exist or are suspected to be uncontrollable or require intravenous administration for treatment; 7. Presents with significant bleeding tendencies, such as active gastrointestinal bleeding, coagulation dysfunction, etc. 8. Has a history of severe allergies or allergic constitutions; 9. Has a history of autoimmune diseases (such as Crohn's disease, rheumatoid arthritis, systemic lupus erythematosus) that require systemic immunosuppressive/systemic disease regulatory drugs within the past two years; 10. Suffered from interstitial lung disease (such as pneumonia, pulmonary fibrosis) during the screening period, or has a clinically significant history of respiratory diseases; 11. Has a history of organ transplantation; 12. Has received gene therapy or other cell therapy targeting the same target within 6 months; 13. Has participated in other clinical trials within 4 weeks prior to the signing of the informed consent form, or the date of signing the informed consent form is still within 5 half-lives of the drug from the last participation in the clinical trial (whichever is longer). 14. Exhibits poor compliance due to physiological, family, social, geographical or other factors and are unable to cooperate and follow the research protocol and follow-up plan; 15. Has contraindications to cyclophosphamide, fludarabine, IL-2 or other drugs related to the study treatment; 16. Has complications that require systemic corticosteroid treatment (≥5 mg/day of dexamethasone or equivalent doses of other corticosteroids) or other immunosuppressive drug treatment within 12 weeks after the start of the study treatment. 17. Lactating women who are unwilling to stop breastfeeding; 18. Has any other conditions that researchers consider unsuitable for inclusion in the group.