A Phase 1b Study Evaluating the Safety and Tolerability of ABT-199 in Combination With Rituximab in Subjects With Relapsed Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma

Inclusion Criteria: * Subject must be greater then or equal to 18 years of age. * Subject must have relapsed Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma. * Subject has an Eastern Cooperative Oncology Group performance score of less than or equal to 1. * Subject must have adequate bone marrow independent of growth factor support per local laboratory reference range at Screening. * Subject must have adequate coagulation, renal, and hepatic function, per laboratory reference range at Screening. Exclusion Criteria: * Chronic lymphocytic leukemia or Small Lymphocytic Lymphoma subject has undergone an allogeneic or autologous stem cell transplant. * Subject has uncontrolled autoimmune hemolytic anemia or thrombocytopenia. * Subject has tested positive for human immunodeficiency virus. * Seropositivity for hepatitis B surface antigen or hepatitis C virus antibody or ribonucleic acid. * History of severe allergic or anaphylactic reactions to rituximab. * Subject has received a live viral vaccine within 6 months prior to the first dose of study drug. * Subject has received a monoclonal antibody for anti-neoplastic intent within 8 weeks prior to the first dose of study drug. * Subject has received any of the following within 14 days prior to the first dose of study drug, or has not recovered to less than grade 2 clinically significant adverse effect(s)/toxicity(s) of the previous therapy: * Any anti-cancer therapy including chemotherapy, immunotherapy, or radiotherapy; * Investigational therapy, including targeted small molecule agents. * Subject has a cardiovascular disability status of New York Heart Association Class greater then or equal to 2. Class 2 is defined as cardiac disease in which subjects are comfortable at rest but ordinary physical activity results in fatigue, palpitations, dyspnea or anginal pain. * Subject has a significant history of renal, neurologic, psychiatric, pulmonary, endocrinologic, metabolic, immunologic, cardiovascular, or hepatic disease that in the opinion of the investigator would adversely affect his/her participating in this study. * Subject has a history of other active malignancies other than CLL/SLL within the past 2 years prior to study entry, with the exception of: * Adequately treated in situ carcinoma of the cervix uteri; * Basal cell carcinoma of the skin or localized squamous cell carcinoma of the skin; * Previous malignancy confined and surgically resected (or treated with other modalities) with curative intent. * Subject has malabsorption syndrome or other condition that precludes enteral route of administration. * Subject exhibits evidence of other clinically significant ongoing or recent condition(s) including, but not limited to: * Ongoing systemic infection (viral, bacterial, or fungal); * Diagnosis of fever and neutropenia within 1 week prior to study drug administration