Monoclonal Antibody RAV12 and Gemcitabine in Treating Patients With Metastatic Pancreatic Cancer

RATIONALE: Monoclonal antibodies, such as RAV12, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Drugs used in chemotherapy, such as gemcitabine, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving RAV12 together with gemcitabine may kill more tumor cells. PURPOSE: This phase II trial is studying the side effects and best dose of monoclonal antibody RAV12 when given together with gemcitabine in treating patients with metastatic pancreatic cancer.

OBJECTIVES: * To determine the maximum tolerated dose of monoclonal antibody RAV12 when administered with standard gemcitabine hydrochloride in patients with previously untreated metastatic pancreatic cancer. * To determine the proportion of these patients surviving at 8 months after initiation of this regimen. * To provide point estimates for response rate and duration of response in patients treated with this regimen. * To define the toxicity profile of this drug in these patients when administered with standard gemcitabine hydrochloride. * To estimate, preliminarily, the progression-free survival and overall survival of these patients after treatment with this regimen. * To explore the utility of the tumor marker, carbohydrate antigen 19-9 (CA19-9), in the assessment of these patients. OUTLINE: This is a dose-escalation study of monoclonal antibody RAV12, followed by an efficacy study. The study is conducted in two segments. * Segment 1 (dose escalation of RAV12): Patients receive gemcitabine hydrochloride IV over 30 minutes on days 1, 8, 15, and 22 of course 1 and on days 1, 8, and 15 of each subsequent course. Patients also receive RAV12 IV once weekly on days 1, 8, and 15 or twice weekly on days 1, 4 or 5, 8, 11 or 12, 15, and 18 or 19 until the maximum tolerated dose (MTD) is reached. Treatment repeats every 28 days in the absence of disease progression or unacceptable toxicity. * Segment 2 (efficacy): Once the MTD has been determined, patients receive RAV12 at the MTD and gemcitabine hydrochloride as in segment 1. Treatment repeats every 28 days in the absence of disease progression or unacceptable toxicity. Blood samples are obtained for pharmacokinetic sampling during the dose-escalation segment of the study. Samples are analyzed to determine plasma concentrations of RAV12, gemcitabine hydrochloride, and difluorodeoxyuridine. Blood samples are also examined periodically for expression of serum biomarkers (i.e., CA19-9, RAAG12, and HACA) and for DNA analysis of Fc-gamma receptor polymorphisms. Archival paraffin blocks or slides from biopsy of primary or metastatic deposit or fresh/frozen tissue may be obtained at baseline for additional correlative studies. Samples are analyzed by immunohistochemistry (IHC) for expression of RAAG12 and for development of a companion RAAG12 diagnostic assay. After completion of study therapy, patients are followed every 8 weeks for up to 3 years. PROJECTED ACCRUAL: This study will accrue a total of 18 patients in the dose-escalation segment and 63 patients in the efficacy segment of the trial.