First-line Treatment With Dual Immunotherapy Combined With Anti-angiogenesis for Unresectable Advanced Malignant Peritoneal Mesothelioma

• Have fully understood the study and voluntarily signed the informed consent;
• Age≥ 18 years, gender not restricted;
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) score 0-1, with an expected survival period of more than 3 months;
• Metastatic or locally advanced unresectable peritoneal mesothelioma confirmed by pathology or histology;
• At least one evaluable lesion (according to RECIST 1.1 criteria);
• Thyroid function, thyroid stimulating hormone (TSH) ≤ upper limit of normal (ULN), subjects with asymptomatic abnormalities of T3, FT3, or FT4 are eligible.
• Adequately controlled blood pressure.
• Have not received any anti-tumor therapy (including chemotherapy, targeted therapy, immunotherapy, etc.) for unresectable advanced or metastatic peritoneal mesothelioma;
• Laboratory test data within 7 days before screening (including 7 days) should meet the following requirements: neutrophil count ≥ 1.5×109/L, platelet count ≥ 75×109/L, hemoglobin ≥ 9g/dL, total serum bilirubin ≤ 3 times the upper limit of normal (ULN); ALT and AST ≤ 5 x ULN; albumin ≥ 28g/L; serum creatinine (Cr) ≤ 1.5 x ULN or creatinine clearance rate (CCr) ≥ 50ml/min; INR≤1.5 x ULN, APTT≤1.5 x ULN; urinalysis showing urine protein \< 2+, for subjects with urine protein ≥ 2+ at baseline, a 24-hour urine collection must be performed and the 24-hour urine protein must be \< 1 g.
• Fertile female must have a negative serum pregnancy test within 3 days before first dose.
• Fertile female and male patients with female partners of childbearing potential must use a highly effective contraceptive method (annual failure rate \< 1 %) from 7 days before first dose until 120 days after the last dose.

Exclusion Criteria:

• Pregnant or lactating women, and women of childbearing age who have not taken adequate contraceptive measures;
• Patients with a history of other malignant tumors within 5 years, except for those with a history of cured cervical carcinoma in situ or non-melanoma skin cancer;
• Patients with the following severe or uncontrolled diseases: severe heart disease, unstable condition despite treatment, myocardial infarction, congestive heart failure, unstable angina pectoris, significant pericardial effusion or unstable arrhythmia within 6 months before enrollment; definite neurological or psychiatric disorders, including dementia or epileptic seizures; severe or uncontrolled infections; active disseminated intravascular coagulation, or patients with obvious bleeding tendencies;
• Participants who received live vaccines (including live attenuated vaccines) within 28 days before first dose.
• Presence of any active autoimmune disease or history of autoimmune disease.
• History of allogeneic haematopoietic stem-cell or solid-organ transplantation.
• Hypertension uncontrolled by medication before enrollment, defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg.
• Other conditions where the investigator deems the patient unsuitable for participation in this trial;