Inclusion Criteria:

• 18 years of age or older
• Endometrial cancer
• Patients must have been treated with one cytotoxic regimen
• At least one measurable lesion
• ECOG performance status less than or equal to 1
• Minimum life expectancy of 3 months
• Adequate renal and hepatic function
• Adequate bone marrow function
• Serum cholesterol <350 mg/dL and triglycerides < 400 mg/dL
• Able to understand and give written informed consent
• Females of childbearing potential must have a negative pregnancy test and use approved contraception from screening to 30 days after the last study drug is given

Exclusion Criteria:

• More than one prior regimen of cytotoxic chemotherapy
• Prior therapy with hormonal agents
• Women who are pregnant or lactating
• Presence of brain or other central nervous system metastases
• Prior therapy with rapamycin, rapamycin analogues or tacrolimus or known sensitivity to these agents
• Anticancer treatment (chemotherapy, radiotherapy) within 4 weeks prior to randomization
• Ongoing toxicity associated with prior anticancer therapy
• Inadequate recovery from any prior surgical procedure or having undergone any major surgical procedure within 2 weeks prior to randomization.
• Another primary malignancy within the past five years (except for non-melanoma skin cancer and cervical carcinoma in situ)
• Known Grade 3 or 4 hypersensitivity to macrolide antibiotics
• Significant uncontrolled cardiovascular disease
• Active infection
• Known HIV infection
• Known Hepatitis B or C infection
• Newly diagnosed (within 3 months before enrollment) or poorly controlled Type 1 or 2 diabetes
• Concurrent treatment with immunosuppressive agents
• A requirement for concurrent treatment with medication that strongly induce or inhibit cytochrome P450 (CYP3A)