Inclusion Criteria: - Patients with confirmed diagnosis of advanced solid tumors (dose-escalation phase) or another solid tumor type based on antitumoral activity (dose-expansion phase) that are not responsive to standard therapy or for which no standard therapy exists - Patients must be 18 years of age or older - Karnofsky Performance Status ≥ 70 - Toxicities from previous cancer therapies must have recovered to CTCAE Grade = or < 2 - Adequate organ and marrow function - Using adequate contraceptive measures, be surgically sterile or post-menopausal Exclusion Criteria: - Concurrently enrolled in another clinical study, except for non-interventiona observational studies, or if in a follow up period from a previous study - Receipt of any investigational anticancer therapy within 30 days prior to the first dose of MEDI3617, or in the case of monoclonal antibodies (eg, bevacizumab), 42 days prior to the first dose of MEDI3617 - Current or previous treatment with angiopoietin inhibitors, or inhibitors of Tie1 or Tie2 including, but not limited to, AMG386, CVX-060, XL880, and XL820 - Any concurrent chemotherapy, radiotherapy, immunotherapy, biologic or hormonal therapy for cancer treatment - Use of immunosuppressive medication or systemic steroids within 7 days prior to first dose of MEDI3617 - Any condition that, in the opinion of the investigator, would interfere with evaluation of the investigational product or interpretation of subject safety or study results - Known bleeding diathesis - Pulmonary hemorrhage or gross hemoptysis within 6 months prior to enrollment - Therapeutic or palliative radiation therapy within 2 weeks prior to enrollment