A Study of Nivolumab in Selected Uterine Cancer Patients

Inclusion Criteria: * Histologically confirmed diagnosis of metastatic or recurrent uterine cancer (endometrial carcinoma, carcinosarcoma, clear cell carcinoma, leiomyosarcoma, undifferentiated sarcoma, high grade endometrial stromal sarcoma) by Memorial Sloan Kettering Cancer Center. Carcinosarcomas, endometrioid and clear cell carcinomas that appears to have arisen in the ovary/fallopian tube or peritoneum are also eligible. Recurrence should not be amenable to curative approaches such as surgical resection or chemoradiotherapy. * Tumor is confirmed to be one of the following: 1. MSI-high, or 2. MMR-deficient, or 3. Hypermutated defined as ≥20 somatic mutations in the tumor by MSK-IMPACT * One or more prior lines of cytotoxic treatment for advanced disease (prior hormonal therapy is not considered to count as prior lines of therapy) * Measurable disease by RECIST 1.1 criteria * No known CNS metastases * ECOG Performance status 0-1 * ECOG Performance status 0-1 * WBC ≥ 2000/uL, ANC ≥ 1500/uL, PLT ≥ 100,000/uL, HGB ≥ 8 g/dL * Serum creatinine ≤ 1.5 x ULN or creatinine clearance of ≥ 40mL/min by Cockroft-Gault formula * AST (SGOT) and ALT (SGPT) ≤ 3 x ULN * Total bilirubin ≤ 1.5 x ULN, except subjects with Gilbert's syndrome who can have total bilirubin ≤ 3.0 mg/dL * Able to sign voluntary written informed consent * Female, 18 years of age or older * Available archival tumor tissue or patient is willing to undergo new biopsy * Premenopausal women of child bearing potential mu…