Fixed Duration Pirtobrutinib and Obinutuzumab in Chronic Lymphocytic Leukemia

This study is testing a combination of two drugs — pirtobrutinib (a targeted oral drug that blocks a protein cancer cells need to grow) and obinutuzumab (an antibody that marks cancer cells for destruction by the immune system) — in people with previously untreated chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), both slow-growing blood cancers. The treatment is designed to be given for a fixed duration rather than indefinitely, which may reduce side effects and treatment burden. **You may be eligible if:** - You have been diagnosed with CLL or SLL according to established medical guidelines - You have measurable disease and an indication that treatment is now needed - You have not yet received any systemic therapy for CLL or SLL - You are 18 or older in sufficient health to participate - You are able to take oral medications **You may NOT be eligible if:** - Your CLL has transformed into a more aggressive lymphoma (Richter's transformation), or cancer has spread to the central nervous system - You have a history of bleeding disorders, recent stroke, or brain hemorrhage in the past 6 months - You have significant heart problems (uncontrolled arrhythmia, severe heart failure, or weak heart function) - You have another active cancer with a life expectancy of less than 2 years - You are currently on other investigational agents Talk to your doctor to see if this trial is right for you.