Background: Identifying new approaches for the treatment of advanced endometrial cancer (EC) is a priority. A platform study design allows for a faster investigation of novel drug combinations. NRG-GY012 is an ongoing platform study investigating drug combinations with the PARP inhibitor olaparib (O) and the anti-angiogenic agent cediranib (C). Results from the first set of arms established improved PFS for combination cediranib/olaparib over C alone, but did not meet its prespecified statistical significance. In this second set of arms, based on preclinical data, we are investigating the combination of O with an AKT inhibitor (capivasertib), O with durvalumab and C with durvalumab compared to the reference arm of C alone. Methods: This is a multicenter randomized four arm study for patients with recurrent, metastatic or persistent EC. Patients are randomized 1:1:1:1 to cediranib PO 30 mg Daily; olaparib 300 mg PO BID and capivasertib 400mg 4 day on/3 off schedule; olaparib 300 mg PO BID and durvalumab 1500mg q28 days; or the combination of cediranib 20 mg PO Daily 5 days on/2 days and durvalumab 1500mg q28. All treatment cycles are 28 days. Primary endpoint is progression free survival (PFS). The study is powered to detect a doubling in median PFS from 3.6 (based on cediranib alone) to 7.2 months with 90% power, using a one-sided test with α = 0.05 per comparison. Forty patients will be enrolled per arm, with an interim futility analysis planned at 50% information time. Eligibility includes endometroid, serous, and mixed histology EC; at least 1 prior line of chemotherapy (no more than 2 lines for metastatic disease), prior endocrine or immunotherapy alone is allowed; prior treatment with lenvatinib and pembrolizumab is excluded. Archival tumor tissue and blood samples are being collected for translational studies. The study is open across the NRG network; 76 of a planned 168 patients are enrolled to date. Safety analysis at the time of 36 patients enrolled did not demonstrate any new safety signals and the study was approved to continue enrollment. Clinical trial information: NCT03660826.