Inclusion Criteria:

          -  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 adenocarcinoma; prior
             combined chemotherapy and radiotherapy is permissible provided the patient has
             measurable disease outside the radiation port; prior therapy must have been completed
             at least 3 weeks prior to starting study therapy

          -  Eastern Cooperative Oncology Group (ECOG) performance status:

               -  For Part I (Arm A, B): 0-1 (Karnofsky > 70%)

               -  For Part II (Arm C): 0-2 (Karnofsky >= 60%)

          -  Life expectancy of greater than 3 months

          -  Absolute neutrophil count >= 1,500/mcL (measured within 14 days prior to
             administration of ABT-888)

          -  Hemoglobin >= 9.0 g/dl (measured within 14 days prior to administration of ABT-888)

          -  Platelets >= 100,000/mcL (measured within 14 days prior to administration of ABT-888)

          -  Total bilirubin =< 2 x institutional upper limit of normal (measured within 14 days
             prior to administration of ABT-888)

          -  Aspartate aminotransferase(AST)/serum glutamic oxaloacetic transaminase (SGOT) and
             alanine aminotransferase(ALT)/serum glutamate pyruvate transaminase (SGPT) =< 2.5 x
             institutional upper limit of normal unless there is evidence of liver metastases in
             which case the AST (SGOT)/ALT (SGPT) must be =< 5 x institutional upper limit of
             normal (measured within 14 days prior to administration of ABT-888)

          -  Creatinine =< 1.5 x upper limit of normal (ULN) (measured within 14 days prior to
             administration of ABT-888)

          -  Measurable disease by RECIST criteria

               -  For the lead-in, non-randomized portion of Part I, either measurable or evaluable
                  disease is acceptable

               -  For Part I, randomized portion, measurable disease is required

          -  If a woman is of child-bearing potential a negative blood or urine pregnancy test is
             required; (the effects of veliparib on the developing human fetus are unknown; for
             this reason and because other therapeutic agents or modalities used in this trial are
             known to be teratogenic, women of child-bearing potential and men must agree to use
             adequate contraception [hormonal or barrier method of birth control; abstinence] prior
             to study entry and for the duration of study participation; should a woman become
             pregnant or suspect she is pregnant while participating in this study, she should
             inform her treating physician immediately)

          -  Ability to understand and the willingness to sign a written informed consent document

        Exclusion Criteria:

          -  Patients who have had chemotherapy or radiotherapy within 3 weeks (6 weeks for
             nitrosoureas or mitomycin C) prior to entering the study or those who have not
             recovered from adverse events due to agents administered more than 3 weeks earlier

               -  For Part I, prior adjuvant therapy with gemcitabine or a fluoropyrimidine therapy
                  is permitted if completed > 6 months prior to recurrence; no prior PARP inhibitor
                  therapy is allowed

               -  For Part II, no prior PARP inhibitor therapy is permitted; up to two prior
                  treatment regimens are permitted as follows: 1 adjuvant and 1 metastatic; 1
                  locally advanced and 1 metastatic; or 2 metastatic, or a variation thereof

          -  Patients may not be receiving any other investigational agents

          -  History of allergic reactions attributed to compounds of similar chemical or biologic
             composition to veliparib or other agents used in study

          -  For Part I: patients with known contraindications to platinum agents are excluded

          -  Uncontrolled intercurrent illness including, but not limited to, ongoing or active
             infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
             arrhythmia, or psychiatric illness/social situations that would limit compliance with
             study requirements

          -  Pregnant women are excluded from this study because veliparib is a PARP inhibitor with
             the potential for teratogenic or abortifacient effects; because there is an unknown
             but potential risk for adverse events in nursing infants secondary to treatment of the
             mother with veliparib, breastfeeding should be discontinued if the mother is treated
             with veliparib; these potential risks may also apply to other agents used in this
             study

          -  Patients with a known active infection, e.g., hepatitis B virus or hepatitis C virus;
             human immunodeficiency virus (HIV)-positive patients who are otherwise well and who do
             not have evidence of significant immune compromise are eligible

          -  Patients with active seizure or history of seizure are not eligible

          -  Patients with uncontrolled central nervous system (CNS) metastasis are not eligible;
             patients with CNS metastases are to be stable for > 3 months after treatment and off
             steroid treatment prior to study enrollment

          -  Patients with prior malignancy successfully treated who are currently stable and on no
             active treatment are eligible

          -  Patients who are unable to swallow pills/capsules are ineligible

          -  Patients with treatment-related acute myeloid leukemia (AML) (t-AML)/myelodysplastic
             syndrome (MDS) or with features suggestive of AML/MDS are ineligible

          -  Patients with prior allogeneic bone marrow transplant or double umbilical cord blood
             transplantation are ineligible