Thymosin alpha-1 (Tα-1) has shown clinical benefits in patients whose immune functions are severely compromised or ineffective. Therefore, this study is attempted to explore whether Tα-1 could be used as a therapeutic option for the treatment of immune-related adverse events (irAEs).

Inclusion Criteria:

1. Subjects who are males or females, aged 18 to 75 years;
2. Subjects who are willing to sign the informed consent forms and receive follow-up visits;
3. Subjects who are cytologically or histologically diagnosed with malignant solid tumors, including but not limited to genitourinary, gynecological, lung, liver, gastrointestinal tumors and melanoma;
4. Subjects with malignant solid tumors who have developed irAEs within 6 months of immune checkpoint inhibitor therapy (CTLA-4, PD-1 and/or PD-L1). The immune checkpoint inhibitors can be used alone, or combined with chemotherapy drugs or other ICIs;
5. Subjects with Grade 2 to 4 skin toxicity, enteritis, pneumonia and hepatitis secondary to ICIs according to CTCAE V5.0 and CSCO guidelines
6. Subjects with sufficient bone marrow functions and meet the following requirements:

(1) Hemoglobin level ≥ 90 g/L (2) Neutrophil count ≥ 1.0×10^9/L (3) Lymphocyte count ≥ 0.5×10^9/L (4) Platelet count ≥75×10^9/L (5) PT, PTT, INR≤1.5 times ULN 7. Subjects with sufficient liver functions: Child-Pugh A and B; 8. Subjects with sufficient renal function: the estimated clearance rate calculated by the Cockroft-Gault formula is ≥40mL/min; 9. Suitable pregnant women who need to take effective contraceptive measures;

Exclusion Criteria:

1. Subjects who have ever immune-related adverse events due to ICI treatment;
2. Subjects who are diagnosed with immunodeficiency disease or are receiving systemic immunosuppressive therapy;
3. Subjects who have skin damage, liver damage, lung damage, etc. caused by the progression of malignant tumors;
4. Subjects who have the thromboembolic disease, biliary tract compression, perfusion injury, opportunistic infection, and liver injury caused by non-ICI drug reactions;
5. Subjects who have abnormal laboratory indicators caused by hepatotropic viruses (such as HAV, HBC, HCV) and non-hepatotropic viruses (such as Epstein-Barr virus, cytomegalovirus, and herpes simplex virus);
6. Subjects who are diagnosed with infectious colitis (e.g., caused by infections such as bacteria, Clostridium difficile, virus, fungus, parasite, etc.);
7. Subjects who suffer from autoimmune diseases, including but not limited to autoimmune hepatitis, primary cholangitis, primary sclerosing cholangitis, rheumatoid arthritis, vitiligo, psoriasis, Crohn's disease, type I diabetes, Grave's disease, etc.;
8. Subjects who suffer from other respiratory diseases with clear etiology, including malignant pulmonary infiltration, active infection, alternative systemic pulmonary toxicity or radiation pneumonitis;
9. Subjects with any other infectious diseases of grade 3 and above;
10. Subjects who have received and used thymosin products or other immunomodulators before enrollment;
11. Subjects who are allergic to thymosin products;
12. Pregnant or breastfeeding women;
13. Subjects who have any known bacterial, fungal or viral infections that may affect their safety or study compliance as deemed by the Investigator within 2 weeks before enrollment;
14. Subjects who have any health conditions that may prevent them from participating in and complying with the procedures related to the study as deemed by the Investigator, including additional laboratory abnormalities or mental illness.