A Ph Ib Study of Fractionated 90Y-hPAM4 Plus Gemcitabine in Pancreatic Cancer Patients Receiving at Least 2 Prior Therapies.

Inclusion Criteria:

- Male or female patients, ≥ 18 years of age, who are able to understand and give
written informed consent

- Histologically or cytologically confirmed pancreatic adenocarcinoma

- Stage IV (metastatic) disease, including patients who underwent surgery but had
incomplete resections

- Previously treated and received two prior treatment regimens for advanced disease

- Karnofsky performance status ≥ 60 % (Appendix A)

- Expected survival ≥ 3 months

- At least 4 weeks beyond major surgery, 2 weeks beyond chemotherapy, radiotherapy,
other experimental treatments

- At least 2 weeks beyond corticosteroids, except low doses (i.e., 20 mg/day of
prednisone or equivalent) to treat nausea or other illness such as rheumatoid
arthritis

- Adequate hematology without ongoing transfusional support (hemoglobin > 9 g/dL, ANC >
1,500 per mm3, platelets > 100,000 per mm3)

- Adequate renal and hepatic function (creatinine and bilirubin ≤ 1.5 X IULN, AST and
ALT ≤ 2.0 X IULN [5.0 X IULN if due to liver metastases])

- Otherwise, all toxicity at study entry ≤ Grade 1 by NCI CTC v3.0 or recovered to
baseline or discussed with and agreed to with Immunomedics' Medical Monitor.

Exclusion Criteria:

- Women who are pregnant or lactating

- Women of childbearing potential and fertile men unwilling to use effective
contraception during study until conclusion of 12-week post-treatment evaluation
period

- Known metastatic disease to the central nervous system

- Presence of bulky disease (defined as any single mass > 10 cm in its greatest
dimension)

- Patients with > Grade 2 nausea or vomiting and/or signs of intestinal obstruction

- Prior radiation dose > 3,000 cGy to the liver, > 2,000 cGy to lungs and kidneys or
prior external beam irradiation to a field that includes more than 30% of the red
marrow

- Patients with non-melanoma skin cancer or carcinoma in situ of the cervix are not
excluded, but patients with other prior malignancies must have had at least a 3-year
disease free interval

- Patients known to be HIV positive, hepatitis B positive, or hepatitis C positive

- Known history of active coronary artery disease, unstable angina, myocardial
infarction, or congestive heart failure present within 6 months, or cardiac
arrhythmia (other than stable atrial fibrillation) requiring anti-arrhythmia therapy

- Known history of active COPD, or other moderate-to-severe respiratory illness present
within 6 months

- Known autoimmune disease or presence of autoimmune phenomena (except rheumatoid
arthritis requiring only low dose maintenance corticosteroids)

- Infection requiring intravenous antibiotic use within 1 week

- Other concurrent medical or psychiatric conditions that, in the Investigator's
opinion, may be likely to confound study interpretation or prevent completion of
study procedures and follow-up examinations