ONC201 and Atezolizumab in Obesity-Driven Endometrial Cancer

In order to participate in this study a subject must meet all of the eligibility criteria outlined below. Inclusion Criteria 1. Ability to understand and willingness to sign a written informed consent obtained to participate in the study and HIPAA authorization for release of personal health information. 2. Age ≥ 18 years at the time of consent. 3. ECOG Performance Status of 0, 1, or 2 4. Histologically confirmed metastatic or recurrent EC (endometrioid, carcinosarcoma, serous, clear cell, adeno-squamous and mixed histologies). 5. Subjects must have measurable disease, defined as at least one lesion that can be accurately measured in at least one dimension in accordance with RECIST criteria 6. Must have radiographic disease progression after at least 1 line of systemic cytotoxic therapy for metastatic disease or with progression within 12 months of completing adjuvant chemotherapy. 7. Life expectancy of at least 3 months. 8. Demonstrate adequate organ function as defined in the table below; all screening labs to be obtained within 72 hours prior to initiating study treatment. Exclusion Criteria 1. Prior treatment with ONC201. 2. Prior treatment with CD137 agonists or immune checkpoint blockade therapies, including antiCTLA-4, and anti PD-L1 therapeutic antibodies 3. Treatment with another investigational agent or participation in another clinical trial within the last 28 days prior to initiating protocol therapy. 4. Subjects who have had chemotherapy or radiotherapy within 4 weeks prior to study treatment or those who have not recovered from adverse events due to agents administered more than 4 weeks prior to initiating protocol therapy. 5. Treatment with therapeutic oral or IV antibiotics within 2 weeks prior to initiation of protocol therapy Subjects receiving prophylactic antibiotics (e.g., to prevent a urinary tract infection or chronic obstructive pulmonary disease exacerbation) are eligible for the study. 6. Treatment with systemic immunostimulatory agents (including, but not limited to, interferon and interleukin 2 \[IL-2\]) within 4 weeks or 5 half-lives of the drug (whichever is longer) prior to initiation of protocol therapy. 7. Treatment with systemic immunosuppressive medication (including, but not limited to, corticosteroids, cyclophosphamide, azathioprine, methotrexate, thalidomide, and anti TNF-agents) within 2 weeks prior to initiation