This is a single-arm, open, multi-center phase 2 study aimed at evaluating the efficacy and safety of 609A combined with doxorubicin hydrochloride in patients with metastatic/unresectable non-specified soft tissue sarcoma. This study is divided into the first part (safety introduction period) and the second part (phase II).~Part 1: Security lead-in period The safety lead-in period adopts a single-arm, open design to evaluate the safety, tolerability and preliminary effectiveness of 609A combined with doxorubicin hydrochloride. Which aimed to explore the Recommended phase II dose (RP2D).~Part 2: Phase 2 This part adopts a single-arm, open, Simon two-stage design to further evaluate the anti-tumor efficacy and safety of 609A combined with doxorubicin hydrochloride.
This is a single arm, open label, phase 2 study aimed to evaluate the efficacy and safety of the combination recombinant anti-PD-1 humanized monoclonal antibody injection (609A) and doxorubicin hydrochloride in the treatment of metastatic/unresectable non-specific soft tissue sarcoma