A Study to Evaluate the Efficacy of Venetoclax Monotherapy in Relapsed/Refractory Participants With Chronic Lymphocytic Leukemia (CLL)

The purpose of this study is to evaluate the efficacy of venetoclax monotherapy in participants with relapsed/refractory CLL with or without the 17p deletion or TP53 mutation, including those who have received prior treatment with a B-cell receptor inhibitor.

Following the Screening period, all eligible participants initiate venetoclax on a once daily (QD) dosing schedule. To mitigate the risk for tumor lysis syndrome (TLS), dosing will start with a 5-week dose titration phase. Participants may receive venetoclax for up to 2 years provided they continue to tolerate the drug, have no evidence of disease progression (based on investigator assessment), do not have unacceptable toxicity and do not meet any of the criteria for subject discontinuation. In countries where venetoclax is not commercially available, participants who continued to derive benefit after 2 years of treatment may extend their treatment for up to 2 additional years in an extended access phase. Participants in the extended access phase of this study who continue to derive benefit from venetoclax after the 2-year extension and are transferring to the venetoclax extension study, Study M19-388 (NCT03844048), may remain in Extended Access for up to 1 additional year or until the extension study is approved and initiated at the site, whichever is sooner.