Testing the Addition of the AKT Inhibitor, Ipatasertib, to Treatment with the Hormonal Agent Megestrol Acetate for Recurrent or Metastatic Endometrial Cancers

Summary

Objectives

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) on days 1-28 and ipatasertib PO QD on days 1-21 of each cycle. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. 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 on days 1-28 of each cycle. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. 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 on days 1-28 and ipatasertib PO QD on days 1-21 of each cycle. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. Patients undergo a CT or MRI during screening, on study, and during follow-up. Patients also undergo collection of blood samples throughout the trial.

After completion of study treatment, patients are followed up at 30 days for the phase I study. Patients are followed up every 3 months for 2 years, then every 6 months for 3 years for the phase II study.