Purpose

This phase III trial studies how well ibrutinib and obinutuzumab with or without venetoclax work in treating patients with chronic lymphocytic leukemia. Ibrutinib may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Obinutuzumab is a monoclonal antibody. It binds to a protein called CD20, which is found on B cells (a type of white blood cell) and some types of cancer cells. This may help the immune system kill cancer cells. Venetoclax is in a class of medications called B-cell lymphoma-2 (BCL-2) inhibitors. It may stop the growth of cancer cells by blocking Bcl-2, a protein needed for cancer cell survival. Giving ibrutinib, obinutuzumab, and venetoclax may work better than giving ibrutinib and obinutuzumab in treating patients with chronic lymphocytic leukemia.