Inclusion Criteria:

        Diagnosis and Criteria for Inclusion:

        All patients:

        To be considered eligible to participate in this study, all of the following requirements
        must be met:

          1. Patient, male or female, is at least 18 years of age.

          2. Patient has a diagnosis of advanced solid malignancy that has failed standard therapy
             or for which standard therapy is not likely to provide meaningful benefit, or patient
             has refused standard therapy.

          3. Patient has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1.

          4. Patient is able to take oral medications.

          5. Female patient, if of childbearing potential, has a negative serum pregnancy test
             within 72 hours prior to taking study drug and agrees to abstain from activities that
             could result in pregnancy from enrollment through 120 days after the last dose of
             study treatment, or be of non-childbearing potential. Non-childbearing potential is
             defined as (by other than medical reasons):

               -  ≥45 years of age and has not had menses for > 1 year.

               -  Amenorrheic for < 2 years without a hysterectomy Post hysterectomy, bilateral
                  oophorectomy, or tubal ligation..

             Note: Abstinence is acceptable if this is the established and preferred contraception
             for the patient.

          6. Male patient agrees to use an adequate method of contraception starting with the first
             dose of study treatment through 120 days after the last dose of study treatment..

          7. Patient is able to understand the study procedures and agrees to participate in the
             study by providing written informed consent.

        Patients with normal hepatic function (Group 1):

        Patients screened for the normal hepatic function group must meet the following additional
        criteria to be eligible for enrollment:

          1. Patient has no history of hepatic impairment.

          2. Patient has liver function test (LFT) results within normal range:

               -  Total bilirubin ≤ ULN

               -  Aspartate aminotransferase (AST) ≤ ULN.

               -  INR ≤1.5 X ULN unless the patient is receiving anticoagulant therapy and the INR
                  is within therapeutic range of intended use of anticoagulants.

          3. Patient has adequate hematologic and renal function as defined below:

               -  Absolute neutrophil count ≥1500/µL

               -  Platelets ≥100,000/µL

               -  Hemoglobin ≥9 g/dL

               -  Serum creatinine ≤1.5 × ULN or a calculated creatinine clearance ≥60 mL/min using
                  the Cockcroft-Gault equation.

        Patients with moderate hepatic impairment (Group 2):

        Patients screened for the moderate hepatic impairment group must meet the following
        additional criteria to be eligible for enrollment:

          1. Patient has stable, moderate hepatic impairment, defined as:

               -  BILI: >1.5 × to 3 × ULN, for at least 2 weeks prior to Day 1

               -  AST: Any value

               -  INR less than 1.8 unless the patient is receiving anticoagulant therapy and the
                  INR is within therapeutic range of intended use of anticoagulants.

          2. Patient has hematologic and renal function as defined below:

               -  Absolute neutrophil count ≥1000/µL

               -  Platelets ≥75,000/µL

               -  Hemoglobin ≥8 g/dL

               -  Serum creatinine ≤1.5 × ULN or a calculated creatinine clearance ≥60 mL/min using
                  the Cockcroft-Gault equation.

          3. Patient's hepatic disease is deemed stable by the Investigator

        Criteria for Exclusion:

        Patients will not be eligible for study entry if any of the following criteria are met:

        All patients:

          1. Patient has undergone palliative radiotherapy within 1 week of study drug
             administration, encompassing >20% of the bone marrow.

          2. Patient is starting chemotherapy within 3 weeks of study drug administration.

          3. Patient has a known hypersensitivity to the components of niraparib or excipients

          4. Patients who received colony-stimulating factors within 2 weeks prior to the first
             dose of study treatment are not eligible.

          5. Patient has persistent chemotherapy associated Grade 2 or greater toxicity except for
             neuropathy, alopecia or fatigue.

          6. Patient has symptomatic uncontrolled brain or leptomeningeal metastases.

          7. Patient has undergone major surgery within 3 weeks of starting the study or patient
             has not recovered from any effects of any major surgery.

          8. Patient is considered a poor medical risk due to a serious, uncontrolled medical
             disorder (other than hepatic impairment) or active, uncontrolled infection.

          9. Patient has received a transfusion (platelets or red blood cells) within 3 weeks of
             receiving niraparib.

         10. Patient is pregnant, breastfeeding, or expecting to conceive children while receiving
             study treatment or for 3 months after the last dose of study treatment.

         11. Patient has a known history of myelodysplastic syndrome (MDS) or acute myeloid
             leukemia (AML).

             NOTE: Exclusion Criteria 12-16 apply patients participating in the PK phase of the
             study.

         12. Patient is currently receiving, or unable to refrain from taking from 4 days prior to
             dosing until the time of the last PK blood draw, any of the following cytochrome (CYP)
             1A2 substrates: alosetron, duloxetine, melatonin, ramelteon, tacrine, tizanidine, and
             theophylline.

         13. Patient is unable to refrain from any intake of grapefruit or grapefruit juice within
             4 days of the first administration of niraparib until the final PK sample collection.

         14. Patient is currently receiving, or unable to refrain from taking from 4 days prior to
             dosing until the last PK blood draw, any of the following P-glycoprotein (P-gp)
             inhibitors: amiodarone, azithromycin, captopril, carvedilol, clarithromycin,
             conivaptan, cyclosporine, diltiazem, dronedarone, erythromycin, felodipine,
             itraconazole, ketoconazole, lopinavir and ritonavir, quercetin, quinidine, ranolazine,
             ticagrelor and verapamil.

         15. Patient is taking proton pump inhibitors, antacids, or histamine 2 (H2) blockers
             within 48 hours prior to niraparib administration, and/or within 6 hours after
             niraparib administration.

         16. Patient has esophagogastrointestinal disease or resection that is likely to interfere
             with the absorption of niraparib.

        Patients with moderate hepatic impairment (Group 2):

        Patients screened for the moderate hepatic impairment group who meet any of the following
        additional criteria will be excluded from the study:

          1. Patient has hepatic encephalopathy, severe portal hypertension and/or porto-systemic
             shunt.

          2. Patient has fluctuating or rapidly deteriorating hepatic function as determined by the
             investigator within the screening period.

          3. Patient has acute liver disease caused by drug toxicity or by an infection.

          4. Patient has biliary obstruction or other causes of hepatic impairment not related to
             parenchymal disorder and/or disease of the liver.

          5. Patient has esophageal variceal bleeding within the past 2 months.

          6. Patient is receiving anticoagulant therapy with warfarin or related coumarins.

          7. Patient has a history of hepatic transplant, systemic lupus erythematosus, or hepatic
             coma.