Sintilimab, Bevacizumab, Pemetrexed, and Cisplatin for Unresectable MPeM

This study is testing a combination of four drugs — sintilimab (an immunotherapy), bevacizumab (a drug that blocks tumor blood supply), pemetrexed, and cisplatin (chemotherapy) — for people with peritoneal mesothelioma, a rare cancer lining the abdomen that cannot be removed by surgery. **You may be eligible if...** - You are 18 or older and have been confirmed to have peritoneal mesothelioma - Your cancer cannot be removed surgically - You are in good physical condition (ECOG 0–1) - You have reasonable organ function (blood counts, liver, kidney) - Your expected survival is at least 3 months - Women of childbearing potential must test negative for pregnancy **You may NOT be eligible if...** - You have active autoimmune disease or are taking immune-suppressing drugs - You have uncontrolled infections, heart problems, or other serious conditions - You have had prior chemotherapy for this cancer - You have brain metastases Talk to your doctor to see if this trial is right for you.