Decitabine and Selinexor in Combination to Reverse Drug Resistance With Standard Chemotherapy in Ovarian Cancer

Inclusion Criteria: * Participants must be greater than or equal to 18 years of age * Participants must have an Eastern Cooperative Oncology Group (ECOG) Performance Status PS less than or equal to 2. * Participants must have histological or cytological proven epithelial ovarian cancer, fallopian tube or primary peritoneal carcinoma with relapse or disease progression after prior treatment by exam, computed tomography (CT), PET/CT, or magnetic resonance imaging (MRI) may be enrolled. All cell types including clear cell carcinoma are eligible. * Participants must have failed or relapsed after a platinum and taxane containing combination * Participants must have adequate hepatic function * Participants must have adequate renal function * Participants must be able to swallow and retain oral medications * Participants must have measurable disease according to Gynecologic Cancer Intergroup CA125 criteria * Participants with stable (for 2 months or longer), treated (by radiotherapy) CNS metastases are eligible * Participants with active hepatitis B virus (Hep B) are allowed if antiviral therapy for hepatitis B has been given for greater than 8 weeks. Exclusion Criteria: * Participants must not have received Selinexor or another XPO1 inhibitor previously. * Participants must not have had any concurrent medical condition or disease (eg, uncontrolled active hypertension, uncontrolled active diabetes, active systemic infection, etc.) * Participants must not have uncontrolled active infection. Participants on prophylactic antibiotics or with a controlled infection within 1 week prior to C1D1 are acceptable. * Participants must not have known intolerance, hypersensitivity, or contraindication to platinum or taxane therapy * Participants must not have active, unstable cardiovascular function * Participants must not have myocardial infarction within 3 months prior to starting * Participants with untreated central nervous system (CNS) metastases are ineligible. * Participants must not have had prior chemotherapy or radiation therapy * Participants must not have DVT related to metastatic disease requiring ongoing anticoagulation.