This study aims to investigate the safety and efficacy of the IL-22BP in patients with refractory malignant solid tumors.

Cancer is a leading global cause of death, with advanced cases posing significant treatment challenges due to low efficacy and severe side effects. Gene therapy, especially mRNA-based immunogene therapy, offers promise. IL-22 promotes tumor progression, and its antagonist, IL-22BP, can inhibit tumor growth.

Patients with refractory, metastatic solid tumors unresponsive to second-line therapy lack viable options. This study aims to establish a novel IL-22BP-based mRNA treatment for advanced cancers.

Inclusion Criteria:

1. Male or female patients: aged ≥ 18 years old and ≤ 70 years old;
2. Patients with histopathologically confirmed, refractory to second-line treatment, advanced recurrent/metastatic malignant solid tumors and without standard clinical treatment regimens (such as patients with advanced soft tissue sarcoma, advanced head and neck squamous cell carcinoma, malignant melanoma, etc.);
3. Eastern Cooperative Oncology Group (ECOG) performance status score: 0 - 1;
4. Expected survival time ≥ 3 months;
5. More than 28 days since the last chemotherapy/radiotherapy/surgery;
6. More than 6 weeks since the last use of nitrosoureas or mitomycin C;
7. Main organ functions are in good condition;
8. Sign a written informed consent form.

Exclusion Criteria:

1. Have participated in other drug clinical trials within 4 weeks;
2. The tumor is located close to major blood vessels or the trachea;
3. Patients with uncontrolled cardiac clinical symptoms or diseases, such as heart failure of NYHA class II or above, unstable angina pectoris, having had a myocardial infarction within 1 year, and having clinically significant supraventricular or ventricular arrhythmias that require treatment or intervention.
4. For female subjects: pregnant or lactating women.
5. Patients have active tuberculosis, bacterial or fungal infections (≥ grade 2 of NCI-CTCAE 5.0); have active HIV infection, active HBV infection, or HCV infection.
6. Those with a history of psychotropic drug abuse who are unable to quit or have mental disorders;
7. Subjects have any active autoimmune diseases or a history of autoimmune diseases (such as, but not limited to: uveitis, enteritis, hypophysitis, nephritis, hyperthyroidism, hypothyroidism; subjects with vitiligo or those whose asthma in childhood has been completely relieved and who do not require any intervention in adulthood can be included; subjects with asthma that requires bronchodilators for medical intervention cannot be included).
8. Subjects are currently receiving immunosuppressive treatment.
9. Have a history of drug abuse or known medical, psychological, or social conditions, such as a history of alcoholism or drug use.
10. Known to be allergic, hypersensitive, or intolerant to the studied IL-22BP (including any excipients). Have a severe allergy history to any drugs, foods, or vaccines in the past, such as anaphylactic shock, allergic laryngeal edema, allergic dyspnea, allergic purpura, thrombocytopenic purpura, local allergic necrotizing reaction (Arthus reaction), etc.
11. From the screening period to 12 months after the completion of drug injection, female subjects have pregnancy plans or the partners of male subjects have pregnancy plans.
12. According to the investigator's judgment, there are concomitant diseases that seriously endanger patient safety or affect the patient's completion of the study.