Assessing the Ability of Combination Treatment With Venetoclax to Permit Time Limited Therapy in Chronic Lymphocytic Leukemia

Inclusion Criteria: * Diagnosis of CLL according to the National Cancer Institute (NCI)/International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria or small lymphocytic lymphoma (SLL) according to the World Health Organization (WHO) criteria. This includes previous documentation of: * Biopsy-proven small lymphocytic lymphoma OR * Diagnosis of CLL according to the NCI/IWCLL criteria as evidenced by all of the following: * Peripheral blood lymphocyte count of greater than 5 x10\^9/L * Immunophenotype consistent with CLL defined as: * The predominant population of lymphocytes share both B-cell antigens (CD19, CD20 \[typically dim expression\], or CD23) as well as CD5 in the absence of other pan-T-cell markers (CD3, CD2, etc). * Clonality as evidenced by kappa or lambda light chain restriction (typically dim immunoglobulin expression) * Negative fluorescent in situ hybridization (FISH) analysis for t(11;14)(IgH/CCND1) on peripheral blood or tissue biopsy (e.g. marrow aspirate) or negative immunohistochemical stains for cyclin D1 staining on involved tissue biopsy (e.g. marrow aspirate or lymph node biopsy) * No prior chemotherapy, BTK inhibitor therapy, venetoclax, small molecule signaling inhibitor, or monoclonal anti-body therapy for treatment of CLL or SLL * Has met at least one of the following indications for treatment: * Evidence of progressive marrow failure as manifested by the development of worsening anemia (hemoglobin \[Hg\]…