A Phase 2 Open-Label Study of the Efficacy and Safety of ABT-199 (GDC-0199) in Chronic Lymphocytic Leukemia (CLL) Subjects With Relapse or Refractory to B-Cell Receptor Signaling Pathway Inhibitor Therapy

Inclusion Criteria:

* Participant must have a diagnosis of chronic lymphocytic leukemia (CLL) that meets 2008 Modified International Workshop on Chronic Lymphocytic Leukemia National Cancer Institute-Working Group (IWCLL NCI-WG) criteria
* Participant has relapsed/refractory disease with an indication for treatment
* Participant has refractory disease or developed recurrence after therapy with a B-cell receptor pathway inhibitor (BCR PI)
* Participant must have an Eastern Cooperative Oncology Group performance score of ≤ 2
* Participant must have adequate bone marrow function at Screening
* Participant must have adequate coagulation profile, renal, and hepatic function, per laboratory reference range at Screening

Exclusion Criteria:

* Participant has undergone an allogeneic stem cell transplant within the past year
* Participant has developed Richter's transformation confirmed by biopsy
* Participant has active and uncontrolled autoimmune cytopenia
* Participant has malabsorption syndrome or other condition that precludes enteral route of administration
* Participant is human immunodeficiency virus (HIV) positive or has chronic hepatitis B or hepatitis C virus requiring treatment
* Participant has known contraindication or allergy to both xanthine oxidase inhibitors and rasburicase