Venetoclax With High-dose Ibrutinib for CLL Progressing on Single Agent Ibrutinib

The purpose of the study is to investigate whether the combination of venetoclax and ibrutinib (administered up to 840 mg per day) might be useful for the treatment of CLL or SLL that is not responding or no longer responding to treatment with ibrutinib alone. The study will evaluate whether this regimen can reduce the amount of cancerous cells in your body. If you agree, you will receive ibrutinib at a dose of up to 840 mg a day by mouth, as well as venetoclax. Although both of these agents are approved by the FDA for the treatment of CLL or SLL, the combination and the dosing schedule of ibrutinib are considered experimental.