FOLFIRI or Modified FOLFIRI and Veliparib as Second Line Therapy in Treating Patients With Metastatic Pancreatic Cancer

Inclusion Criteria: * Patients must have histologically or cytologically documented pancreatic adenocarcinoma; patients with pancreatic neuroendocrine tumors, lymphoma of the pancreas, or ampullary cancer are not eligible * Patients must have metastatic disease that is measurable; computed tomography (CT) scans or magnetic resonance imaging (MRI)s used to assess measurable disease must have been completed within 28 days prior to registration; CT scans or MRIs used to assess non-measurable disease must have been completed within 42 days prior to registration; all disease must be assessed and documented on the Baseline Tumor Assessment Form * Patients must not have history of brain metastases * Patients must have had one and only one prior regimen of systemic therapy for metastatic disease unless the patient meets the criteria below * Prior systemic therapy and chemoradiotherapy for treatment of resectable, borderline resectable or locally advanced unresectable disease is allowed and does not count toward prior therapy for metastatic disease * Patients who received systemic therapy with gemcitabine/nab-paclitaxel for resectable or borderline/locally advanced unresectable disease and progressed with metastatic disease within 3 months of the past dose of systemic therapy are eligible * Patients must have completed systemic therapy at least 14 days prior to registration, any surgical procedure must have been performed at least 14 days prior to registration, and radiation therapy …