This clinical trial is focused on studying Chronic Lymphocytic Leukemia (CLL), a type of cancer that affects the blood and bone marrow. The study is testing a treatment that involves a combination of two medications: Gazyvaro (also known as obinutuzumab) and Venetoclax (also referred to by its code name ABT-199). Gazyvaro is given as an infusion, which means it is administered directly into the bloodstream through a vein, while Venetoclax is taken orally as a tablet.

The purpose of the study is to evaluate the effectiveness and safety of these medications when used together in a specific sequence. Initially, patients will receive Gazyvaro alone, followed by a combination of Gazyvaro and Venetoclax, and then Venetoclax by itself. The study aims to determine if this treatment can help patients with CLL who are not suitable for more intensive treatments. The trial will also explore different ways of continuing Venetoclax treatment, either as a standard maintenance therapy or guided by specific markers in the body.

Participants in the study will undergo a series of treatment cycles over a period of time, with regular monitoring to assess their response to the treatment. The study will look at various outcomes, including the absence of cancer cells in the bone marrow and the overall health and quality of life of the participants. The trial is designed to provide valuable information on how these medications can be used effectively in treating CLL.