PRIMARY OBJECTIVES:~I. Determine the toxicity of ipatasertib in combination with megestrol acetate in women with metastatic grade 1-2 endometrioid endometrial cancer and establish the recommended phase II dose. (Phase I) II. Compare the progression free survival of the combination of ipatasertib with megestrol acetate to megestrol acetate alone among women with metastatic grade 1-2 endometrioid adenocarcinoma of the endometrium. (Phase II) III. Compare the toxicity of the combination of ipatasertib with megestrol acetate to megestrol acetate alone. (Phase II)~SECONDARY OBJECTIVES:~I. Compare objective response rate per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 between the two arms.~II. Examine the pharmacokinetics of ipatasertib + megestrol acetate to assess potential drug-drug interactions.~III. Assess the association between biomarkers and response to therapy.~EXPLORATORY OBJECTIVE:~I. Explore whether pS6/total S6 and pPRAS40/total PRAS40 expression is impacted by the use of ipatasertib and megestrol acetate.~OUTLINE: This is a phase Ib, dose de-escalation study of ipatasertib followed by a phase II study.~PHASE Ib: Patients receive megestrol acetate orally (PO) once daily (QD) and ipatasertib PO QD throughout the trial. Patients undergo a computed tomography (CT) or magnetic resonance imaging (MRI) during screening, on study, and during follow-up. Patients also undergo collection of blood samples throughout the trial.~PHASE II: Patients are randomized to 1 of 2 arms.~ARM I: Patients receive megestrol acetate PO QD throughout the trial. Patients undergo a CT or MRI during screening, on study, and during follow-up. Patients also undergo collection of blood samples throughout the trial.~ARM II: Patients receive megestrol acetate PO QD and ipatasertib PO QD throughout the trial. Patients undergo a CT or MRI during screening, on study, and during follow-up. Patients also undergo collection of blood samples throughout the trial.
This phase Ib/II trial tests the safety, side effects, best dose, and effectiveness of the combination of ipatasertib with megestrol acetate to megestrol acetate alone in patients with endometrial cancer that has come back (recurrent) or has spread to other places in the body (metastatic). Ipatasertib may stop the growth of tumor cells and may kill them by blocking some of the enzymes needed for cell growth. Megestrol acetate lowers the amount of estrogen and also blocks the use of estrogen made by the body. This may help stop the growth of tumor cells that need estrogen to grow. The combination of ipatasertib and megestrol acetate may be more effective in treating endometrial cancer than megestrol acetate alone.