Venetoclax tablets will be administered orally.

PFS by investigator assessment is defined as the duration from date of randomization to date of PD or death due to any cause, whichever occurs first.

OS is defined as the time from date of randomization to date of death from any cause.

MRD-negative rate is defined as the percentage of participants who reach MRD-negative status (that is, less than [<] 1 chronic lymphocytic leukemia (CLL) cell per 10,000 leukocytes or <0.01 percentage [%]) in the peripheral blood.

An adverse event (AE) is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study.

An AE is any untoward medical occurrence in a clinical study participant administered a pharmaceutical (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the intervention. Severity will be graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 5.0. Severity scale ranges from Grade 1 (Mild) to Grade 5 (Death). Grade 1= Mild, Grade 2= Moderate, Grade 3= Severe, Grade 4= Life-threatening and Grade 5= Death related to adverse event.

Percentage of participants with rate of discontinuation due to AEs will be reported.

Percentage of participants with dose reduction due AEs will be reported.

The adherence rate is defined as the percentage of total dose taken over the total dose prescribed.

Duration of treatment is defined as the time period in days between the date of first study treatment administration and date of last administration.

Time to worsening is defined as time interval (months) from randomization to first observation of deterioration. Time to worsening as measured by EQ-5D-5L will be reported.

Time to worsening is defined as time interval from randomization to first observation of deterioration. Time to worsening as measured by EORTC QLQ-C30 will be reported.

Time to worsening is defined as time interval from randomization to first observation of deterioration. Time to worsening as measured by EORTC QLQ-CLL17 will be reported.

Time to Worsening is defined as time interval (months) from randomization to first observation of deterioration. Time to worsening as measured by FACIT-fatigue total score will be reported.