Lag-3 and Gemcitabine for Treatment of Advanced Pancreas Cancer

Inclusion Criteria: * Patient must have a newly diagnosed, histologically or cytologically confirmed diagnosis of pancreatic adenocarcinoma (primary tumor or metastasis). The histological slides or blocks must be available for review. * Patient must have advanced disease (characterized by metastasis or locally advanced disease), or unable to undergo surgical treatment due to extent of disease or pre-existing health conditions precluding surgical treatment. * Measurable or evaluable disease: RECIST Criteria will be used to assess and survey extent of disease * Patients must be ≥ 18 years old. * Performance Status: Karnofsky Performance Status (KPS) ≥ 70 * Life Expectancy \> 12 weeks. * No previous history of chemotherapy for pancreas cancer in the metastatic setting prior to the start of protocol treatment. * Patients must have recovered from uncontrolled, intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris or cardiac arrhythmia. * Patients must have adequate bone marrow function defined as an absolute neutrophil count \>1,500/mm3, platelet count \>100,000/mm3 and hemoglobin \>10 g/dl. * Patients must have adequate renal function defined as serum creatinine ≤ 2.0 mg/dl or creatinine clearance ≥ 60 ml/min/1.73m2 for patients with creatinine levels above 2.0 mg/dl. * Patients must have adequate hepatic function with total bilirubin ≤ 1.5 times the institutional normal value and AST ≤ 2 times the institutional normal value. * Patient must have no prior or current active autoimmune disease requiring management with immunosuppression. This includes inflammatory bowel disease, systemic vasculitis, scleroderma, psoriasis, hemolytic anemia, immune-mediated thrombocytopenia, rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, sarcoidosis or other rheumatologic disease. Asthma and chronic obstructive pulmonary disease that does not require daily systemic corticosteroids is acceptable. * The patient with previous history of malignancy is eligible for this study only if the patient meets the following criteria for cancer survivor: * (i) patient has undergone potentially curative therapy for all prior malignancies; * (ii) patient has been considered disease free for at least 5 years. * For all sexually active patients, the use of adequate barrier contraception (hormonal or barrier method of birth control) will be required during therapy, prior to study entry and for the duration of study participation. Patients must agree to refrain from becoming pregnant 2 years after beginning treatment with IMP321. Non-pregnant status will be determined in all women of childbearing potential. * After being informed of the treatment involved, patients must give written consent. The patient should not have any serious medical or psychiatric illness that would prevent either the giving of informed consent or the receipt of treatment. Exclusion Criteria: * Patient is currently receiving other investigational agents. * Pregnant and nursing women patients are not eligible. * Patients known to be HIV (patient self-report) positive are ineligible because of the potential inability to modulate immune responses. * Patients with a QTc of \>460 msec.