Puxitatug Samrotecan (AZD8205) Monotherapy vs Chemotherapy in B7-H4-selected Endometrial Cancer (Bluestar-Endometrial01)

The target population of interest in this study is participants with B7-H4-selected advanced/metastatic EC who have progressed on or after platinum-based chemotherapy and anti-PD-1/anti-PD-L1 therapy, either separately or in combination and should have received no more than 2 prior lines of therapy in advanced/metastatic setting. Participants will be randomized in a 1:1 ratio to Puxi-Sam (arm A) or physician's choice of chemotherapy (arm B; doxorubicin or paclitaxel). The total study size will be approximately 700 eligible participants. During the treatment period, participants will receive Puxi-Sam IV Day 1 Q3W (Arm A) or either doxorubicin treatment IV Day 1 Q3W or paclitaxel treatment IV on Days 1, 8, and 15 in 28-day cycle (Arm B). This study aims to see if Puxi-Sam allows participants to live longer without their endometrial cancer getting worse, or simply to live longer, compared to participants receiving standard of care chemotherapy. This study is also looking to see how the treatment and the endometrial cancer affects participants' quality of life.