The purpose of this study is to investigate the activity of MORAb-009 when added to a standard regimen of gemcitabine in patients with previously untreated unresectable stage 3 or 4 pancreatic cancer.

Inclusion Criteria:

1. Female or male subjects, ≥ 18 years of age, with cytologically or histologically confirmed diagnosis of pancreatic adenocarcinoma.

2. Must have measurable disease, as defined by RECIST or evaluable by clinical signs/symptoms (e.g. ascites, pleural effusion, or lesions of less than 2 cm) supported by biomarker, radiologic, or pathologic studies conducted within 4 weeks prior to study entry.

3. Must have unresectable disease and have received no prior chemotherapy or radiation therapy for their pancreatic cancer.

4. Karnofsky performance status of greater than or equal to 70 %.

5. Female subjects of childbearing potential and all male subjects must be surgically sterile or consent to use a medically acceptable method of contraception throughout the study period.

6. Other significant medical conditions must be well-controlled and stable in the opinion of the investigator for at least 30 days prior to Study Day 1.

7. Laboratory and clinical results within the 2 weeks prior to Study Day 1 as follows:

   Absolute neutrophil count (ANC) ≥ 1.5 x 109/L Platelet count ≥ 100 x 109/L Hemoglobin ≥ 9 g/dL Serum bilirubin ≤ 2.0 mg/dL Aspartate transaminase (AST)* ≤ 5 x upper limit of normal (ULN) Alanine transaminase (ALT)* ≤ 5 x ULN Alkaline phosphatase* ≤ 5 x ULN Serum creatinine ≤ 2.0 mg/dL Stenting to reduce liver functions to qualifying levels is permitted.

   * Subjects with liver function abnormalities greater than the ULN are eligible only if in the opinion of the investigator they are due to disease obstruction of the bile ducts or metastatic disease.

8. Must be willing and able to provide written informed consent.

Exclusion Criteria:

1. Known central nervous system (CNS) tumor involvement.
2. Evidence of other active malignancy requiring treatment.
3. Clinically significant heart disease (e.g., congestive heart failure of New York Heart Association Class 3 or 4 angina not well controlled by medication, or myocardial infarction within 6 months).
4. Electrocardiogram (ECG) demonstrating clinically significant arrhythmias (Note: Subjects with chronic atrial arrhythmia, i.e., atrial fibrillation or paroxysmal supraventricular tachycardia [SVT], are eligible).
5. Active serious systemic disease, including active bacterial or fungal infection.
6. Active viral hepatitis or symptomatic human immunodeficiency virus (HIV) infection.
7. Prior chemotherapy or radiation therapy for their pancreatic cancer.
8. Breast-feeding, pregnant, or likely to become pregnant during the study.
9. No other concurrent immunotherapy (e.g., immunosuppressants or chronic use of systemic corticosteroids with the exception that low-dose corticosteroids are allowed)
10. Known hypersensitivity to a monoclonal antibody or biologic therapy.