A Study of AGS-1C4D4 Given in Combination With Gemcitabine in Subjects With Metastatic Pancreatic Cancer

Inclusion Criteria: * Pathologically confirmed metastatic adenocarcinoma of the pancreas (AJCC Stage IV). Subjects with islet cell neoplasms are excluded * Non-measurable or measurable disease based on the RECIST criteria * Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 * Life expectancy of \> 3 months * Hematologic function, as follows: * Absolute neutrophil count (ANC) ≥ 1.5 x 109/L * Platelet count ≥ 100 x 109/L * Hemoglobin ≥ 9 g/dL (transfusion independent) * Renal function, as follows: * Creatinine ≤ 2.0 mg/dL * Hepatic function, as follows: * Aspartate aminotransferase (AST) ≤ 2.5 x ULN or ≤ 5 x ULN if known liver metastases. * Alanine aminotransferase (ALT) ≤ 2.5 x ULN or ≤ 5 x ULN if known liver metastases * Bilirubin ≤ 2 x ULN * INR \< 1.3 (or ≤ 3 if on warfarin for therapeutic anti-coagulation) Exclusion Criteria: * Prior systemic therapy for metastatic pancreatic cancer * Subjects who have received adjuvant treatment with gemcitabine and who had relapse metastatically are allowed * Subjects with advanced local disease who have received treatment with gemcitabine and in whom progression has been observed with the onset of metastases less than 6 months are excluded * Chemotherapy and/or radiation within 4 weeks of study enrollment * Prior monoclonal antibody therapy within 60 days of study enrollment * Known brain or leptomeningeal disease * History of other primary malignancy, unless: * Curatively resected non-melanomatous skin cancer * Other malignancy curatively treated with no known active disease present and no treatment administered for the last 3 years * Active angina or Class III or IV Congestive Heart Failure (New York Heart Association CHF Functional Classification System) * Use of any investigational product within 4 weeks of study enrollment * Major surgery (that requires general anesthesia) within 4 weeks before study enrollment * Women who are pregnant (confirmed by positive pregnancy test) or lactating * Man or woman of childbearing potential not consenting to use adequate contraceptive precautions during the course of the study and for 4 weeks after the last AGS-1C4D4 and/or gemcitabine infusion administration * Subject known to be human immunodeficiency, hepatitis B or hepatitis C virus positive * Active serious infection not controlled with antibiotics