A Study of Onapristone ER Alone Or In Combination With Anastrozole in Gynecologic Cancers That Respond to Progesterone

Inclusion Criteria

• Histologically confirmed diagnosis at MSK of either (1) granulosa cell ovarian cancer, (2) low grade serous ovarian/ primary peritoneal cancer, or (3) endometrioid endometrial cancer; with PR expression ≥1% by IHC on archival tissue taken within the prior 3 years or new biopsy if no archival tissue is available. IHC results do not have to be from MSK.
• Measurable disease as defined by RECIST 1.1. Measurable disease is defined as at least one lesion that can be accurately measured in at least one dimension. Each lesion must be ≥10mm when measured by CT or MRI. Lymph nodes must be ≥15mm in short axis when measured by CT or MRI
• Patients must have had one prior chemotherapy regimen for management of disease. Note: additional lines of chemotherapy, biologic or immunotherapy are allowed.
• Recovery from effects of recent surgery, radiotherapy, or chemotherapy
• At least 4 weeks out from their last dose of radiation therapy
• At least 4 weeks post-op from any major surgical procedure
• At least 3 weeks out from their last dose of chemotherapy and/or biologic/targeted therapy
• Must be ≥ 18 years of age
• Karnofsky Performance Status (KPS) of ≥ 70%
• Women of child-bearing potential must have a negative pregnancy test within 14 days prior to commencement of study treatment
• Women of child bearing potential must use an effective form of contraception during study and for at least 6 months after completion of study treatment
• Laboratory Test Findings performed within 14 days prior to initiation of study drug showing:
• Bone marrow function:
• Absolute neutrophil count (ANC) ≥ 1,000/mcL
• Platelets ≥ 75,000/mcL
• Hemoglobin ≥ 8 g/dL
• Renal function:

°Creatinine ≤ 1.5 x ULN

• Hepatic function:
• Bilirubin ≤ 1.5 x ULN
• AST and ALT ≤ 2.5 x ULN
• Resolution of all acute toxic effects of prior therapy to NCI CTCAE (Version 5.0) Grade ≤ 1, with the exception of unresolved Grade 2 neuropathy and Grade 2 alopecia, which are allowed
• Patient has recovered from any prior radiotherapy
• Patients must be able to swallow tablets whole, without crushing

Exclusion Criteria

• History of another invasive malignancy (other than non-melanoma skin cancer or curatively treated in situ carcinoma) with evidence of disease within the past 3 years
• History of prior hormonal therapy (i.e., megesterol acetate, tamoxifen or aromatase inhibitors) for treatment of cancer within 28 days before starting study drug
• Any psychological, familial, sociological or geographic condition that would potentially hamper compliance with the study protocol
• Known brain metastasis which have not been treated or showed stability for ≥ 6 months
• Patient has received an oral or IV corticosteroid within the prior 28 days and requires chronic corticosteroid therapy (excludes use of steroid premeds for CT allergy)
• Uncontrolled hypertension (systolic BP ≥ 160 mmHg or diastolic BP ≥ 95mmHg) despite medical treatment. Patients with a history of hypertension are allowed provided blood pressure is controlled by anti-hypertensive treatment.
• Clinically significant heart disease as evidenced by myocardial infarction or arterial thrombotic event within the past 6 months, severe or unstable angina, or New York Heart Association (NYHA) Class II-IV heart disease or cardiac ejection fraction measurement of < 50% at baseline
• Refractory nausea and vomiting, requirement for parenteral hydration and/or nutrition, drainage gastrostomy tube, malabsorption, external biliary shunt, or significant small bowel resection that would preclude adequate study drug absorption
• Anticipated or ongoing administration of anti-cancer therapies other than those administered in this study
• Use of any prescription medication during the prior 28 days of first onapristone dosing that the investigator judges is likely to interfere with onapristone activity; specifically strong inhibitors or inducers, or sensitive substrates of cytochrome P450 CYP3A4. Investigators should consult