Durvalumab in Combination With Tremelimumab in Subjects With Advanced Rare Solid Tumors

Inclusion Criteria: * Diagnosis of a rare advanced solid malignancy meeting EORTC criteria. * Subjects must have failed or been ineligible to receive standard treatment options if available. * Subjects must be amenable to biopsy of a tumor site or have recent (\< 2 years) archival material available. * ECOG performance status of 0 to 2. * Life expectancy \> 3 months. * Adequate normal organ and marrow function including: hemoglobin \> 9.0 g/dl; ANC \> 1500 per mm3; platelet count \> 100,000 per mm3; bilirubin \< 1.5 x ULN; ALT/AST \< 2.5 x ULN unless liver metastases present in which case must be \< 5 x ULN; creatinine clearance \> 40 ml/min by Cockcroft-Gault or 24 hour urine collection Exclusion Criteria: * Previous treatment with durvalumab or tremelimumab. * Prior treatment with any checkpoint inhibitor (including anti-CTLA-4, anti-PD-1 and anti-PD-L1). * Rare malignancies under investigation in other studies including thymic carcinoma, certain sarcomas, and neuroendocrine tumors. * Untreated central nervous system metastatic disease. * Active or documented autoimmune disease within previous 2 years. * Uncontrolled psoriasis. * Prior chemotherapy within 28 days of the first dose of durvalumab or tremelimumab. * Steroid exposure within 28 days of the first dose of durvalumab or tremelimumab with the exceptions of intranasal and inhaled corticosteroids or systemic corticosteroids at physiological doses, which are not to exceed 10 mg/day of prednisone, or an equivalent co…