Gemcitabine Hydrochloride and Cisplatin With or Without Veliparib or Veliparib Alone in Treating Patients With Locally Advanced or Metastatic Pancreatic Cancer

Inclusion Criteria: * Male or female patients with cytologically or histologically confirmed locally advanced or metastatic pancreas adenocarcinoma with a BRCA1 or 2 or PALB2 mutation confirmed by report from Myriad Genetics (United States of America \[USA\]); reports from other molecular diagnostic companies can be used to confirm mutations as well; BRCA 1 or 2 or PALB2 mutation can be confirmed locally for all international sites * For part I, non-randomized, lead-in portion, patients with a known BRCA 1 or 2 or PALB2 mutation are eligible along with patients who potentially may have a likelihood of having a BRCA mutation (e.g., personal or family history of breast, pancreas, ovary, endometrial, prostate or other likely related malignancy) * For part I, randomized portion, a known BRCA 1 or 2 or PALB2 mutation is required * For part I (arms A, B): Patients can have either locally advanced or metastatic pancreas adenocarcinoma for which no prior therapy has been administered for either locally advanced or metastatic disease; prior adjuvant therapy is permissible if gemcitabine or a fluoropyrimidine was administered with or without radiation and if disease recurrence has been documented at least 6 months after completion of adjuvant therapy * For part II (arm C): Patients can have either locally advanced or metastatic pancreas adenocarcinoma; up to two prior treatment regimens are permissible (excluding a prior PARP inhibitor) for either localized or metastatic pancreas…