Inclusion Criteria:

          1. Confirmed deleterious or suspected deleterious germline BRCA1 or BRCA2 mutation

          2. Locally advanced or metastatic breast cancer despite standard therapy and the
             following:

               1. Histologically or cytologically confirmed HER2(-) breast cancer (TNBC or estrogen
                  receptor-positive and/or PR+)

               2. ≤ 2 prior lines of chemotherapy in advanced or metastatic setting

               3. Prior platinum therapy allowed as long as no disease progression while on
                  treatment, or if given in neoadjuvant/adjuvant setting with ≥ 6 months from last
                  platinum to relapse

               4. Prior therapy with an anthracycline and a taxane in neoadjuvant/adjuvant or
                  metastatic setting

               5. Archival tumor tissues will be collected from all patients, if available

               6. For HR(+)/HER2(-) breast cancer only: patients must have received and progressed
                  on at least one endocrine therapy either in adjuvant or metastatic setting, or
                  have disease that the treating physician believes to be inappropriate for
                  endocrine therapy

          3. Measurable disease as defined per RECIST, version 1.1

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

          5. Adequate hematologic and organ function

        Exclusion Criteria:

          1. Unresolved acute effects of prior therapy of ≥ Grade 2

          2. Prior treatment with a PARP inhibitor

          3. Chemotherapy, radiotherapy, biologic therapy, immunotherapy, investigational agent,
             anticancer Chinese medicine, or anticancer herbal remedies ≤ 14 days (or ≤ 5 half
             lives, if applicable, whichever is shorter) prior to Day 1 of Cycle 1

          4. Major surgical procedure, open biopsy, or significant traumatic injury ≤ 14 days prior
             to Day 1 of Cycle 1, or anticipation of need for major surgical procedure during the
             course of the study

          5. Diagnosis of MDS

          6. Other diagnosis of malignancy

          7. Untreated and/or active brain metastases.

          8. Active infection requiring systemic treatment, active viral hepatitis, or active
             tuberculosis

          9. Clinically significant cardiovascular disease

         10. Pregnancy or nursing

         11. Known history of intolerance to the excipients of the BGB-290 capsule