Venetoclax as Consolidation in CLL Patients Treated With BTK Inhibitor Monotherapy

Inclusion Criteria: * 1\. Age: 18-80 years-old. * 2\. Patients must have a diagnosis of CLL/SLL. * 3\. Detectable MRD by flow cytometry (10\^-4 sensitivity) in the peripheral blood. * 4\. Patients who are on BTK inhibitor monotherapy for more than 6 months. This study includes patients who are taking one of the following BTK inhibitors: ibrutinib, zanubrutinib, orelabrutinib, and acalabrutinib. * 5\. Patients need to have a response of at least PR (CR/PR) to BTK inhibitor monotherapy. * 6\. Eastern Cooperative Oncology Group (ECOG) Performance Status ≤ 2. * 7\. Patients must have adequate renal and hepatic function: * Serum bilirubin ≤ 1.5 × upper limit of normal (ULN) or ≤ 3 × ULN for patients with Gilbert's disease; * Serum creatinine clearance of ≥ 50 ml/min (calculated or measured); * ALT and AST ≤ 3.0 × ULN, unless clearly due to disease involvement. * 8\. Adequate bone marrow function: * Platelet count of greater than 50,000/µl, with no platelet transfusion in prior 2 weeks; * ANC ≥ 1000/µl in the absence of growth factor support unless due to compromised bone marrow production from CLL, indicated by ≥ 80% CLL in marrow; * Hemoglobin ≥ 8g/dL. * 9\. Adequate cardiac function, as assessed by: * Absence of uncontrolled cardiac arrhythmia; * Echocardiogram demonstrating LVEF ≥ 35%; * NYHA functional class ≤ 2. * 10\. Ability to provide informed consent and adhere to the required follow-up. Exclusion Criteria: * 1\. Richter transformation. * 2\. Active malignancy requirin…