This is a multi-center, open label, phase II clinical study. The safety and effectiveness of 609A in the treatment of unresectable or advanced undifferentiated pleomorphic sarcoma are mainly evaluated by ORR (based on the results of CT/MRI examination of subjects during treatment).
The main purpose of this study is to evaluate the efficacy and safety of recombinant anti-PD-1 humanized monoclonal antibody injection (609A) in patients with unresectable or advanced undifferentiated pleomorphic sarcoma