Early Clonal Dynamics During Venetoclax Treatment for Relapsed or Refractory Chronic Lymphocytic Leukemia (CLL)

Patients with CLL/SLL will enroll on the study. Subjects will be treated at the NIH Clinical Center for the duration of the ramp-up phase of venetoclax. After the ramp-up phase is complete, subjects will be transitioned to the care of their local hematologist/oncologist and receive venetoclax monotherapy or in combination with other agent(s) at the discretion of the treating oncologist. Subjects will have the option to follow-up at the NIH every 6 months (from initiation of venetoclax) and at (suspected) progression.