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

This is a Phase III, 2-arm, randomized, open label, multicenter, global study assessing the efficacy and safety of puxitatug samrotecan compared to physician's choice of chemotherapy (doxorubicin or paclitaxel) in participants with B7-H4 selected advanced/metastatic EC that progressed following platinum based chemotherapy and anti-PD-1/anti-PD-L1 therapy.

The main inclusion criteria include but are not limited to the following: * Histologically confirmed diagnosis of endometrial carcinoma or carcinosarcoma. * Recurrent/metastatic EC ie, with radiological or objective evidence of recurrence or progression. * Has received prior platinum-based chemotherapy and anti-programmed cell death 1 protein (PD-1)/anti- programmed cell death ligand 1 (PD-L1) therapy, either separately or in combination. * A WHO/ECOG performance status of 0 or 1 at Screening. * Has radiographically measurable disease by RECIST 1.1 The main exclusion criteria include but are not limited to the following: * Had uterine sarcomas or uterine neuroendocrine carcinoma. * Has had a recurrence of endometrial carcinoma or carcinosarcoma more than \> 12 months after completing platinum-based therapy administered in the curative-intent setting without any additional platinum-based therapy received in the recurrent setting. * Had previously received treatment with any therapy (approved or investigational) that contained a TOP1i including ADCs . * Had previously received treatment with Puxi-Sam or another B7-H4 targeting agent. * History of (non-infectious) ILD/pneumonitis that required steroids, has current ILD/pneumonitis, or where suspected ILD/pneumonitis cannot be ruled out by imaging at screening. * Has clinically severe pulmonary compromise resulting from intercurrent pulmonary illnesses. * Active or previously documented autoimmune or inflammatory disorders