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