Zanubrutinib and Venetoclax as Initial Therapy for Chronic Lymphocytic Leukemia (CLL) With Response-based Obinutuzumab

Description

This is an open label, phase II, investigator-initiated clinical trial of 50 subjects. Subjects with CLL/SLL who have treatment indications per the 2018 International Workshop for CLL (iwCLL) will be eligible to enroll. The investigators hypothesize that anti-CD20 therapy may not be required for all patients and a response-adapted strategy will prevent over treatment of a significant number of patients and reduce toxicity of treatment while still achieving a high rate of MRD negativity. The investigators also hypothesize that late addition of anti-CD20 therapy can eliminate low burden residual disease in subjects and maximize undetectable MRD negativity in subjects who remain MRD positive.

All subjects will initiate induction therapy with 3 cycles of zanubrutinib monotherapy in order to debulk subjects and mitigate tumor lysis risk. This lead-in period will then be followed by 12 cycles of zanubrutinib and venetoclax combination. Standard ramp-up protocols for venetoclax based on TLS risk assessed prior to C4D1 will be utilized. All subjects will complete 12 cycles of zanubrutinib and venetoclax combination therapy or 15 cycles of total treatment. Peripheral blood and bone marrow MRD assessments will occur at C16D1. Subjects will continue on combination treatment for an additional 1 month while results of MRD testing are obtained. In total, all subjects will be on treatment for at least 16 full cycles. Subjects that meet definition of MRD negativity will stop therapy at C17D1 and enter an observation phase with study visits every 3 months. Subjects that meet definition of MRD positivity will continue combination therapy with zanubrutinib and venetoclax, but will also receive 6 cycles of obinutuzumab starting at C17D1. In this subgroup, peripheral blood and bone marrow MRD assessments will occur after an additional 6 cycles of the triplet combination therapy (C23D1) at which point all subjects will stop study treatment regardless of MRD status.