Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (pre-randomization phase). Participants with confirmed uMRD were randomized to receive ibrutinib 420 mg orally once daily on a continuous schedule until MRD-positive relapse, PD, or unacceptable toxicity, whichever was earlier. After MRD-positive relapse or disease progression (PD) by iwCLL criteria, subjects can reintroduce 400 mg venetoclax with a 5-week ramp up. If venetoclax was reintroduced, venetoclax treatment was to continue at the dose of 400 mg/day for up to approximately 2 years (cumulative), or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (pre-randomization phase). Participants with confirmed uMRD were randomized to receive placebo orally once daily on a continuous schedule until MRD-positive relapse, PD or unacceptable toxicity, whichever was earlier. If MRD-positive relapse or PD is confirmed after restaging per iwCLL criteria, participants could first reintroduce oral daily ibrutinib with the option of subsequently reintroducing 400 mg venetoclax with a 5-week ramp up, if subsequent disease relapse per iwCLL criteria occurs after ibrutinib reintroduction. If venetoclax was reintroduced, venetoclax treatment was to continue at the dose of 400 mg/day for up to approximately 2 years (cumulative), or earlier PD or unacceptable toxicity.

P-value is from Z test for the difference of two proportions based on Kaplan-Meier estimates with standard error of each arm computed using Greenwood's formula.

comparison: ibrutininb vs. placebo

Participants in the FD cohort without del 17p abnormality (according to non-missing baseline fluorescent in situ hybridization [FISH] results) received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until PD or unacceptable toxicity, whichever was earlier.

Participants received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until disease progression or unacceptable toxicity, whichever was earlier.

Participants with confirmed progression per 2008 International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria after completion of the fixed duration regimen could be retreated with continuous single agent ibrutinib until disease progression or unacceptable toxicity, whichever was earlier, because it is an established standard of care for treatment of relapsed chronic lymphocytic leukemia (CLL).

For participants who experienced durable efficacy after ibrutinib plus venetoclax (ie, time to progression after fixed duration regimen is completed of >2 years), the ibrutinib plus venetoclax fixed duration treatment regimen may have been repeated based on Investigator's clinical discretion and Medical Monitor's approval. Retreatment was for 15 cycles, until disease progression (PD) or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (pre-randomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants in the FD cohort without del 17p abnormality (according to non-missing baseline fluorescent in situ hybridization [FISH] results) received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until PD or unacceptable toxicity, whichever was earlier.

Participants received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until disease progression or unacceptable toxicity, whichever was earlier. Participants with confirmed progression per 2008 International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria after completion of the fixed duration regimen could be retreated with continuous single agent ibrutinib until disease progression or unacceptable toxicity, whichever was earlier, because it is an established standard of care for treatment of relapsed chronic lymphocytic leukemia (CLL). For participants who experienced durable efficacy after ibrutinib plus venetoclax (ie, time to progression after fixed duration regimen is completed of >2 years), the ibrutinib plus venetoclax fixed duration treatment regimen may have been repeated based on Investigator's clinical discretion and Medical Monitor's approval.

Retreatment was for 15 cycles, until disease progression (PD) or unacceptable toxicity.

Participants in the FD cohort without del 17p abnormality (according to non-missing baseline fluorescent in situ hybridization [FISH] results) received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until PD or unacceptable toxicity, whichever was earlier.

Participants received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until disease progression or unacceptable toxicity, whichever was earlier. Participants with confirmed progression per 2008 International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria after completion of the fixed duration regimen could be retreated with continuous single agent ibrutinib until disease progression or unacceptable toxicity, whichever was earlier, because it is an established standard of care for treatment of relapsed chronic lymphocytic leukemia (CLL). For participants who experienced durable efficacy after ibrutinib plus venetoclax (ie, time to progression after fixed duration regimen is completed of >2 years), the ibrutinib plus venetoclax fixed duration treatment regimen may have been repeated based on Investigator's clinical discretion and Medical Monitor's approval.

Retreatment was for 15 cycles, until disease progression (PD) or unacceptable toxicity.

Participants in the FD cohort without del 17p abnormality (according to non-missing baseline fluorescent in situ hybridization [FISH] results) received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until PD or unacceptable toxicity, whichever was earlier.

Participants received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until disease progression or unacceptable toxicity, whichever was earlier. Participants with confirmed progression per 2008 International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria after completion of the fixed duration regimen could be retreated with continuous single agent ibrutinib until disease progression or unacceptable toxicity, whichever was earlier, because it is an established standard of care for treatment of relapsed chronic lymphocytic leukemia (CLL). For participants who experienced durable efficacy after ibrutinib plus venetoclax (ie, time to progression after fixed duration regimen is completed of >2 years), the ibrutinib plus venetoclax fixed duration treatment regimen may have been repeated based on Investigator's clinical discretion and Medical Monitor's approval.

Retreatment was for 15 cycles, until disease progression (PD) or unacceptable toxicity.

Participants in the FD cohort without del 17p abnormality (according to non-missing baseline fluorescent in situ hybridization [FISH] results) received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until PD or unacceptable toxicity, whichever was earlier.

Participants received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until disease progression or unacceptable toxicity, whichever was earlier. Participants with confirmed progression per 2008 International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria after completion of the fixed duration regimen could be retreated with continuous single agent ibrutinib until disease progression or unacceptable toxicity, whichever was earlier, because it is an established standard of care for treatment of relapsed chronic lymphocytic leukemia (CLL). For participants who experienced durable efficacy after ibrutinib plus venetoclax (ie, time to progression after fixed duration regimen is completed of >2 years), the ibrutinib plus venetoclax fixed duration treatment regimen may have been repeated based on Investigator's clinical discretion and Medical Monitor's approval.

Retreatment was for 15 cycles, until disease progression (PD) or unacceptable toxicity.

Participants in the FD cohort without del 17p abnormality (according to non-missing baseline fluorescent in situ hybridization [FISH] results) received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until PD or unacceptable toxicity, whichever was earlier.

Participants received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until disease progression or unacceptable toxicity, whichever was earlier. Participants with confirmed progression per 2008 International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria after completion of the fixed duration regimen could be retreated with continuous single agent ibrutinib until disease progression or unacceptable toxicity, whichever was earlier, because it is an established standard of care for treatment of relapsed chronic lymphocytic leukemia (CLL). For participants who experienced durable efficacy after ibrutinib plus venetoclax (ie, time to progression after fixed duration regimen is completed of >2 years), the ibrutinib plus venetoclax fixed duration treatment regimen may have been repeated based on Investigator's clinical discretion and Medical Monitor's approval.

Retreatment was for 15 cycles, until disease progression (PD) or unacceptable toxicity.

Participants received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until disease progression or unacceptable toxicity, whichever was earlier. Participants with confirmed progression per 2008 International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria after completion of the fixed duration regimen could be retreated with continuous single agent ibrutinib until disease progression or unacceptable toxicity, whichever was earlier, because it is an established standard of care for treatment of relapsed chronic lymphocytic leukemia (CLL). For participants who experienced durable efficacy after ibrutinib plus venetoclax (ie, time to progression after fixed duration regimen is completed of >2 years), the ibrutinib plus venetoclax fixed duration treatment regimen may have been repeated based on Investigator's clinical discretion and Medical Monitor's approval.

Retreatment was for 15 cycles, until disease progression (PD) or unacceptable toxicity.

Participants received 420 mg of single agent ibrutinib for first 3 cycles followed by ibrutinib plus venetoclax combination treatment (ibrutinib 420 mg and venetoclax 400 mg orally once daily on a continuous schedule) for 12 cycles (a cycle is defined by 28 days) or until disease progression or unacceptable toxicity, whichever was earlier. Participants with confirmed progression per 2008 International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria after completion of the fixed duration regimen could be retreated with continuous single agent ibrutinib until disease progression or unacceptable toxicity, whichever was earlier, because it is an established standard of care for treatment of relapsed chronic lymphocytic leukemia (CLL). For participants who experienced durable efficacy after ibrutinib plus venetoclax (ie, time to progression after fixed duration regimen is completed of >2 years), the ibrutinib plus venetoclax fixed duration treatment regimen may have been repeated based on Investigator's clinical discretion and Medical Monitor's approval.

Retreatment was for 15 cycles, until disease progression (PD) or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.

Participants received 420 mg of single-agent ibrutinib for the first 3 cycles followed by ibrutinib plus venetoclax combination treatment for at least 12 cycles (a cycle is defined as 28 days) prior to randomization (prerandomization phase). Participants who completed the planned pre-randomization treatment were eligible to be randomized according to their confirmed undetectable minimal residual disease (uMRD) status: Participants with confirmed uMRD were randomized to receive blinded ibrutinib 420 mg or placebo orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. Participants with uMRD not confirmed were randomized to receive open-label ibrutinib 420 mg or open-label ibrutinib 420 mg plus venetoclax 400 mg orally once daily on a continuous schedule until PD or unacceptable toxicity, whichever was earlier. The venetoclax could be administered cumulative from pre-randomization to randomization phase at the dose of 400 mg/day for up to approximately 2 years, or earlier PD or unacceptable toxicity.