This phase II trial studies how well the combination of ibrutinib and venetoclax works in treating patients with chronic lymphocytic leukemia whose cancer has stopped responding to ibrutinib alone. Both ibrutinib and venetoclax may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Giving ibrutinib and venetoclax together after development of ibrutinib resistance may work better than discontinuing ibrutinib and switching to other chemotherapy drugs.
PRIMARY OBJECTIVES: I. Overall response rate to combination ibrutinib and venetoclax after 12 cycles (intervention cohort). II. Rate of mutation negative status after 12 cycles of combination venetoclax and ibrutinib (intervention cohort ). SECONDARY OBJECTIVES: I. Incidence of BTK C481S mutations during ibrutinib treatment (observation cohort). II. Progression-free survival after development of a BTK C481S mutation (observation cohort). III. Progression-free and overall survival after adding venetoclax to ibrutinib (intervention cohort). IV. Type and incidence of adverse events during combination ibrutinib and venetoclax treatment in this patient population (intervention cohort). EXPLORATORY OBJECTIVES: I. Determine patient and disease characteristics associated with clinical disease progression in a univariable and multivariable analysis (observation cohort). II. Determine the changes in the allelic frequency of ibrutinib resistance mutations after their development (observation cohort) and after venetoclax is added (intervention cohort). III. Determine novel resistance mechanisms to ibrutinib and ibrutinib/venetoclax combination therapy by whole exome and ribonucleic acid (RNA) sequencing at baseline and clinical relapse. IV. Perform BH3 profiling and correlate with response to combination venetoclax and ibrutinib therapy. OUTLINE: This is a dose-escalation study of venetoclax. OBSERVATION COHORT: Patients who are taking ibrutinib enter Observation cohort and undergo screening every 3 months for development for genetic mutations. If mutations develop, patients undergo increased screening for development of clinical disease progression. Patients who develop clinical disease progression with or without mutations enter the Intervention cohort. INTERVENTION COHORT: Patients receive venetoclax orally (PO) daily and ibrutinib PO once daily (QD) on days 1-28. Cycles repeat every 28 days in the absence of disease progression or unacceptable toxicity. Patients who achieve minimal residual disease (MRD) negative complete remission (CR) after 12 or 24 cycles continue receiving ibrutinib PO QD on days 1-28 in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 3 months for 2 years and then every 6 months thereafter.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Given PO
Given PO
Overall response rate (ORR) (intervention cohort)
Defined as the percentage of patients who have achieved any response better than stable disease after 12 cycles of combination ibrutinib and venetoclax treatment. All eligible patients who take one study dose of venetoclax will be considered evaluable and included in the denominator when calculating the ORR. ORR will be estimated with a 95% exact binomial confidence interval at the response assessment after 12 cycles of combination ibrutinib and venetoclax therapy, and 24 if applicable.
Time frame: After 12 cycles of combination therapy, assessed up to 3 years
Rate of mutation negative status (intervention cohort)
Rate of mutation negative status will be estimated with a 95% exact binomial confidence interval at the response assessment after 12 cycles of combination ibrutinib and venetoclax therapy, and 24 if applicable.
Time frame: After 12 cycles of combination therapy, assessed up to 3 years
Incidence of BTK C481S mutations (observation cohort)
Person-time incidence of developing a BTK C481S mutation will be calculated by dividing the number of new mutations observed while on ibrutinib therapy by the total number of months patients are receiving ibrutinib and were at risk.
Time frame: Up to 3 years
Progression-free survival (PFS) after development of a BTK C481S mutation (observation cohort)
Will be calculated in the observation cohort from the date a BTK C481S mutation was first reported until the date of clinical disease progression by International Workshop on Chronic Lymphocytic Leukemia (IWCLL) 2018 criteria or death from any cause, whichever occurs first.
Time frame: Up to 3 years
PFS after adding venetoclax to ibrutinib (intervention cohort)
PFS will be calculated in the intervention cohort from the start date of combination therapy (C1D1) until the date of progressive disease or death from any cause. Will be described using the method of Kaplan-Meier.
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Time frame: Up to 3 years
Overall survival (OS) after adding venetoclax to ibrutinib (intervention cohort)
OS will be calculated in the intervention cohort from the start date of combination therapy (C1D1) until the date of progressive disease or death from any cause. Will be described using the method of Kaplan-Meier.
Time frame: Up to 3 years
Incidence of adverse events (intervention cohort)
Graded per National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0 with the exception of hematologic adverse events. Adverse events will be summarized by type, severity and perceived attribution. Hematologic adverse events will be graded according to CLL-specific criteria described in the IWCLL 2018 guidelines. The maximum grade for each type of toxicity will be recorded for each patient and frequency tables will be reviewed to determine the toxicity patterns. In addition, will also summarize the number of patients who discontinue combination therapy due to adverse events.
Time frame: Up to 3 years