Duvelisib With Obinutuzumab in Patients With CLL/SLL Previously Treated With a BTKi (SYNCHRONY)

Inclusion Criteria: * ≥18 years of age * Diagnosis of Chronic lymphocytic leukemia or Small lymphocytic lymphoma that meets at least one of the International Workshop on Chronic Lymphocytic Leukemia (IWCLL) 2008 criteria for treatment (Binet Stage ≥ B and/or Rai Stage ≥ I with symptoms) * Measurable disease with a lymph node or tumor mass \>1.5 cm in at least one dimension as assessed by computed tomography (CT) * Previous exposure to BTKi therapy and meets at least one of the below criteria: * Progressive disease while receiving a BTKi therapy, or stable disease as best response after 12 months of receiving a BTKi therapy * Discontinued a BTKi therapy due to BTKi treatment-related intolerance * Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2 (corresponds to Karnofsky Performance Status \[KPS\] ≥60%) * Subjects must be able to receive outpatient treatment and laboratory monitoring (where specifically indicated) at the institution that administers study drug for the entire treatment period Exclusion Criteria: * Richter's transformation or prolymphocytic leukemia * Refractory to obinutuzumab (defined as progression or relapse \<12 months of receiving obinutuzumab monotherapy or \<24 months of receiving an obinutuzumab-containing regimen) * Progressive disease while previously receiving a PI3K inhibitor (e.g. GS-1101 \[idelalisib\], duvelisib) or a serious/severe AE related to PI3K inhibitor treatment * History of severe reaction to prior monoclonal antibody therapy (defined as a Grade 4 event and/or requiring permanent discontinuation) * Human immunodeficiency virus (HIV) or Human T Cell Lymphotropic Virus 1 (HTLV-1) infection * Prior, current, or chronic hepatitis B or hepatitis C infection * History of tuberculosis treatment within the preceding 2 years