Inclusion Criteria:

• Age ≥ 18 years.
• Diagnosis of chronic lymphocytic leukemia (CLL) per diagnostic criteria and relapsed or refractory CLL per the iwCLL guidelines.
• Previously treated with 1-3 lines of therapy (e.g. completed ≥ two treatment cycles per therapy), including at least one standard chemotherapy-containing regimen.
• Patients previously treated with bendamustine only if their duration of response was ≥ 24 months.
• Eastern Cooperative Oncology Group (ECOG) performance score of ≤ 1.
• Adequate bone marrow function.
• Adequate renal and hepatic function.
• Patients must use effective birth control throughout study until 1 year after rituximab treatment; female patients must not be pregnant or breast-feeding.

Exclusion Criteria:

• Transformation of CLL to aggressive non-Hodgkin lymphoma or CNS involvement by CLL.
• Undergone an allogenic stem cell transplant.
• A history of significant renal, neurologic, psychiatric, endocrine, metabolic, immunologic, cardiovascular or hepatic disease.
• Hepatitis B or C or known HIV positive.
• Receiving warfarin treatment.
• Received an anti-CLL monoclonal antibody within 8 weeks prior to the first dose of study drug.
• Received any anti-cancer or investigational therapy within 14 days prior to the first dose of study drug or has not recovered from previous therapy.
• Received CYP3A4 inhibitors (such as fluconazole, ketoconazole and clarithromycin) or inducers (such as rifampin, carbamezapine, phenytoin, St. John's Wort) within 7 days prior to the first dose of GDC-0199.
• Prior GDC-0199 treatment.
• Patients with another cancer, history of another cancer considered uncured on in complete remission for < 5 years, or currently under treatment for another suspected cancer except non-melanoma skin cancer or carcinoma in situ of the cervix that has been treated or excised and is considered resolved.
• Malabsorption syndrome or other condition that precludes enteral route of administration.
• Other clinically significant uncontrolled condition(s) including, but not limited to, systemic infection (viral, bacterial or fungal).
• Vaccination with a live vaccine within 28 days prior to randomization