A Prospective Cohort of Obinutuzumab and Chlorambucil (GC) Chemotherapy for the Treatment of Elderly Patients With Chronic Lymphocytic Leukemia Including Next- Generation Sequencing (NGS)-Based Assessment

Inclusion Criteria: * Eligible subjects will be considered for inclusion in this study if they meet all of the following criteria: 1. Newly diagnosed chronic lymphocytic leukemia 2. Age≥ 70 years 3. Satisfy the one of indications for starting treatment guideline <!-- --> 1. Evidence of progressive marrow failure (anemia, thrombocytopenia) 2. AIHA, thrombocytopenia refractory to steroids 3. Massive (\>6cm, LCM) or symptomatic splenomegaly 4. Massive nodes (\>10 cm) or symptomatic 5. Progressive lymphocytosis 6. 50% increase over 2 months or LDT \< 6 months 7. Constitutional Symptoms : weight loss \> 10% in 6 months, significant fatigue, fever \>38 over 2 weeks, night sweat \> 1month 4. ECOG performance status 0-2 5. Total bilirubin ≤ 1.5 x ULN (upper limit of normal) 6. Aspartate aminotransferase (AST) ≤ 5 x ULN, (ALT) ≤ 5 x ULN 7. Creatinine ≤ 3.0 x ULN 8. Provide informed consent Ability to understand the purpose and risks of the study and provide signed and dated informed consent and authorization to use protected health information Exclusion Criteria: 1. Unmet NGS samples by bone marrow biopsy or peripheral bloods at diagnosis 2. Hairy cell leukemia or prolymphocytic leukemia 3. Uncontrolled infection 4. Therapy history with combined chemotherapy or biologic therapy prior to registration 5. History of thromboembolic episodes ≤ 3 months prior to registration 6. Active hepatitis B or C with uncontrolled disease 7. Active other malignancy requiring treatment that would interfere with the assessments of response of the lymphoma to protocol treatment 8. Any severe and/or uncontrolled medical conditions or other conditions that could adversely impact their ability to participate in the study 9. Concurrent participation in another therapeutic clinical trial.