Key Inclusion Criteria:

        In order to be eligible to participate in any phase of this study, an individual must meet
        all of the following criteria:

          1. Provision of written informed consent.

          2. Age ≥ 18 years or the minimum legal adult age (whichever is greater) at the time of
             informed consent.

          3. Adequate hematologic and organ function as defined by the following criteria:

               1. Absolute neutrophil count (ANC) ≥ 1.5 × 10^9/L; excluding measurements obtained
                  within 7 days after daily administration of filgrastim/sargramostim or within 3
                  weeks after administration of pegfilgrastim.

               2. Platelet count ≥ 100 × 10^9/L; excluding measurements obtained within 3 days
                  after transfusion of platelets.

               3. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 3 × upper
                  limit of normal (ULN). If liver function abnormalities are due to underlying
                  liver metastases, AST and ALT ≤ 5 x ULN.

               4. Total serum bilirubin ≤ 1.5 × ULN or ≤ 3 × ULN in the case of Gilbert's disease.

               5. Serum creatinine ≤ 1.5 x ULN or creatinine clearance (CrCl) ≥ 60 mL/min.

          4. Female subjects of childbearing potential must have a negative serum beta human
             chorionic gonadotropin test.

          5. Male subjects and female subjects of childbearing potential must agree to use an
             effective method of contraception per institutional standard prior to the first dose
             and for 90 days after the last dose of ZN-c3.

        Individuals must meet the additional criteria in order to be eligible to participate in
        Phase 1:

          1. Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2.

          2. Measurable or evaluable disease per RECIST version 1.1.

        Individuals must meet these additional criteria in order to be eligible to participate in
        Phase 2 Single Agent part of the study:

          1. ECOG performance status ≤ 1.

          2. Measurable disease per RECIST version 1.1.

        Individuals must meet these additional criteria in order to be eligible to participate in
        Phase 2 combination with a PARP inhibitor:

          1. ECOG performance status ≤ 1.

          2. Measurable disease per RECIST version 1.1.

        Individuals must meet these additional criteria in order to be eligible to participate in
        Phase 2 combination with a PD-1 inhibitor:

          1. ECOG performance status ≤ 1.

          2. Measurable disease per RECIST version 1.1.

        Key Exclusion Criteria:

          1. Any of the following treatment interventions within the specified time frame prior to
             Cycle 1 Day 1:

               1. Major surgery within 28 days.

               2. Radiation therapy within 21 days.

               3. Any prior systemic therapy regardless of the stop date, but the subject must have
                  recovered to eligibility levels from prior toxicity.

               4. Autologous or allogeneic stem cell transplant within 3 months.

               5. Current use of an investigational agent that is not expected to be cleared by the
                  first dosing of study drug or that has demonstrated to have prolonged side
                  effects. Subjects should have recovered from the side effects to a Grade 0 or 1
                  (except alopecia).

          2. A serious illness or medical condition(s) including, but not limited to, the
             following:

               1. Brain metastases that require immediate treatment or are clinically or
                  radiologically unstable.

               2. Leptomeningeal disease that requires or is anticipated to require immediate
                  treatment.

               3. Myocardial impairment of any cause resulting in heart failure by New York Heart
                  Association Criteria Class III or IV.

               4. Other severe acute or chronic medical or psychiatric condition or laboratory
                  abnormality that may increase the risk associated with study participation or
                  study drug administration, or may interfere with the interpretation of study
                  results, and in the judgment of the Investigator would make the subject
                  inappropriate for entry into this study.

               5. Significant gastrointestinal abnormalities

               6. Active or uncontrolled infection.

          3. Unresolved toxicity of Grade > 1 attributed to any prior therapies (excluding Grade 2
             neuropathy, alopecia or skin pigmentation).

          4. Prior therapy with ZN-c3 or known hypersensitivity to any drugs similar to ZN-c3 in
             class.

          5. Subjects with active (uncontrolled, metastatic) second malignancies or requiring
             therapy.