Assessment of response was performed by the investigator according to the iwCLL guidelines. PD was defined as occurrence of one of the following events: appearance of any new extra nodal lesion; new palpable lymph node (greater than [>] 1.5 centimeters [cm]); unequivocal progression of non-target lesion; an increase of greater than or equal to (>/=) 50 percent (%) compared to baseline in splenomegaly, hepatomegaly, number of blood lymphocytes with lymphocyte count >/=5000 per microliter (mcL), or in longest diameter of any extra nodal lesion; transformation to a more aggressive histology; decrease of >/=50% compared to baseline in platelet or neutrophil count; or decrease in hemoglobin level by >2 grams per deciliter (g/dL) or to less than [<] 10 g/dL. Percentages are rounded off.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

PFS was defined as the time from randomization until first occurrence of PD/relapse as assessed by the investigator using iwCLL guidelines, or death from any cause, whichever occurred first. PD: occurrence of one of the following: new lesion; new palpable lymph node (>1.5 cm); unequivocal progression of non-target lesion; increase of >/=50% in splenomegaly, hepatomegaly, blood lymphocytes with count >/=5000/mcL, longest diameter of any lesion; transformation to more aggressive histology; decrease of >/=50% in platelet or neutrophil count, or hemoglobin level by >2 g/dL or to <10 g/dL. Participants who had not progressed, relapsed, or died at the time of analysis, were censored on the date of last assessment. In case of no disease assessment after baseline, PFS was censored at the time of randomization+1 day. The median PFS was estimated using Kaplan-Meier method and the 95% confidence interval (CI) was computed using method of Brookmeyer and Crowley.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

Assessment of response was performed by the IRC according to the iwCLL guidelines. PD was defined as occurrence of one of the following events: appearance of any new extra nodal lesion; new palpable lymph node (>1.5 cm); unequivocal progression of non-target lesion; an increase of >/=50% compared to baseline in splenomegaly, hepatomegaly, number of blood lymphocytes with lymphocyte count >/=5000/mcL, or in longest diameter of any extra nodal lesion; transformation to a more aggressive histology; decrease of >/=50% compared to baseline in platelet or neutrophil count; or decrease in hemoglobin level by >2 g/dL or to <10 g/dL. No new IRC data was generated post the primary analysis.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

PFS was defined as the time from randomization until first occurrence of PD/relapse as assessed by the IRC using iwCLL guidelines, or death from any cause, whichever occurred first. PD: occurrence of one of the following: new lesion; new palpable lymph node (>1.5 cm); unequivocal progression of non-target lesion; increase of >/=50% in splenomegaly, hepatomegaly, blood lymphocytes with count >/=5000/mcL, longest diameter of any lesion; transformation to more aggressive histology; decrease of >/=50% in platelet or neutrophil count, or hemoglobin level by >2 g/dL or to <10 g/dL. Participants who had not progressed, relapsed, or died at the time of analysis, were censored on the date of last assessment. In case of no disease assessment after baseline, PFS was censored at the time of randomization+1 day. The median PFS was estimated using Kaplan-Meier method and the 95% CI was computed using method of Brookmeyer and Crowley. No new IRC data was generated post the primary analysis.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

Assessment of response was performed by the investigator according to the iwCLL guidelines. PD was defined as occurrence of one of the following events: appearance of any new extra nodal lesion; new palpable lymph node (>1.5 cm); unequivocal progression of non-target lesion; an increase of >/=50% compared to baseline in splenomegaly, hepatomegaly, number of blood lymphocytes with lymphocyte count >/=5000/mcL, or in longest diameter of any extra nodal lesion; transformation to a more aggressive histology; decrease of >/=50% compared to baseline in platelet or neutrophil count; or decrease in hemoglobin level by >2 g/dL or to <10 g/dL. Percentages are rounded off.

Analysis was performed on ITT population participants with 17p deletion as identified by FISH test.

PFS was defined as the time from randomization until first occurrence of PD/relapse as assessed by the investigator using iwCLL guidelines, or death from any cause, whichever occurred first. PD: occurrence of one of the following: new lesion; new palpable lymph node (>1.5 cm); unequivocal progression of non-target lesion; increase of >/=50% in splenomegaly, hepatomegaly, blood lymphocytes with count >/=5000/mcL, longest diameter of any lesion; transformation to more aggressive histology; decrease of >/=50% in platelet or neutrophil count, or hemoglobin level by >2 g/dL or to <10 g/dL. Participants who had not progressed, relapsed, or died at the time of analysis, were censored on the date of last assessment. In case of no disease assessment after baseline, PFS was censored at the time of randomization+1 day. The median PFS was estimated using Kaplan-Meier method and the 95% CI was computed using method of Brookmeyer and Crowley.

Analysis was performed on ITT population participants with 17p deletion as identified by FISH test.

Assessment of response was performed by the IRC according to the iwCLL guidelines. PD was defined as occurrence of one of the following events: appearance of any new extra nodal lesion; new palpable lymph node (>1.5 cm); unequivocal progression of non-target lesion; an increase of >/=50% compared to baseline in splenomegaly, hepatomegaly, number of blood lymphocytes with lymphocyte count >/=5000/mcL, or in longest diameter of any extra nodal lesion; transformation to a more aggressive histology; decrease of >/=50% compared to baseline in platelet or neutrophil count; or decrease in hemoglobin level by >2 g/dL or to <10 g/dL. No new IRC data was generated post the primary analysis.

Analysis was performed on ITT population participants with 17p deletion as identified by FISH test.

PFS was defined as the time from randomization until first occurrence of PD/relapse as assessed by the IRC using iwCLL guidelines, or death from any cause, whichever occurred first. PD: occurrence of one of the following: new lesion; new palpable lymph node (>1.5 cm); unequivocal progression of non-target lesion; increase of >/=50% in splenomegaly, hepatomegaly, blood lymphocytes with count >/=5000/mcL, longest diameter of any lesion; transformation to more aggressive histology; decrease of >/=50% in platelet or neutrophil count, or hemoglobin level by >2 g/dL or to <10 g/dL. Participants who had not progressed, relapsed, or died at the time of analysis, were censored on the date of last assessment. In case of no disease assessment after baseline, PFS was censored at the time of randomization+1 day. The median PFS was estimated using Kaplan-Meier method and the 95% CI was computed using method of Brookmeyer and Crowley. No new IRC data was generated post the primary analysis.

Analysis was performed on ITT population participants with 17p deletion as identified by FISH test.

Response was assessed by investigator according to iwCLL guidelines and was confirmed by repeat assessment >/=4 weeks after initial documentation. CR: peripheral blood lymphocytes <4000/mcL; absence of any new lesion, nodal disease, lymphadenopathy, hepatomegaly, splenomegaly, and constitutional symptoms; neutrophils >1500/mcL, platelets >100000/mcL, hemoglobin >11.0 g/dL without need for transfusion or exogenous growth factors; normocellular bone marrow with <30% lymphocytes; no lymphoid nodules. CRi: fulfilling all CR criteria but persistent cytopenia. PR: >/=50% reduction in two of following: peripheral blood lymphocytes, lymphadenopathy, spleen and/or liver enlargement; and 1 of following: neutrophils >1500/mcL, platelets >100000/mcL, hemoglobin >11.0 g/dL or >/=50% improvement without need for transfusion or exogenous growth factors. nPR: fulfilling all CR criteria but presence of lymphoid nodules. 95% CI was computed using Pearson-Clopper method.Percentages are rounded off.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

Response was assessed by IRC according to iwCLL guidelines and was confirmed by repeat assessment >/=4 weeks after initial documentation. CR: peripheral blood lymphocytes <4000/mcL; absence of any new lesion, nodal disease, lymphadenopathy, hepatomegaly, splenomegaly, constitutional symptoms; neutrophils >1500/mcL, platelets >100000/mcL, hemoglobin >11.0 g/dL without need for transfusion or exogenous growth factors; normocellular bone marrow with <30% lymphocytes; no lymphoid nodules. CRi: fulfilling all CR criteria but persistent cytopenia. PR: >/=50% reduction in 2 of following: peripheral blood lymphocytes, lymphadenopathy, spleen and/or liver enlargement; 1 of following: neutrophils >1500/mcL, platelets >100000/mcL, hemoglobin >11.0 g/dL or >/=50% improvement without need for transfusion or exogenous growth factors. nPR: fulfilling all CR criteria but presence of lymphoid nodules. 95% CI was computed using Pearson-Clopper method.No new IRC data was generated post primary analysis.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

Response was assessed by investigator according to iwCLL guidelines and was confirmed by repeat assessment >/=4 weeks after initial documentation. CR: peripheral blood lymphocytes <4000/mcL; absence of any new lesion, nodal disease, lymphadenopathy, hepatomegaly, splenomegaly, and constitutional symptoms; neutrophils >1500/mcL, platelets >100000/mcL, hemoglobin >11.0 g/dL without need for transfusion or exogenous growth factors; normocellular bone marrow with <30% lymphocytes; no lymphoid nodules. CRi: fulfilling all CR criteria but persistent cytopenia. PR: >/=50% reduction in 2 of following: peripheral blood lymphocytes, lymphadenopathy, spleen and/or liver enlargement; and 1 of following: neutrophils >1500/mcL, platelets >100000/mcL, hemoglobin >11.0 g/dL or >/=50% improvement without need for transfusion or exogenous growth factors. nPR: fulfilling all CR criteria but presence of lymphoid nodules. 95% CI was computed using Pearson-Clopper method. Percentages are rounded off.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

Response was assessed by the IRC according to the iwCLL guidelines and was confirmed by repeat assessment >/=4 weeks after initial documentation. CR: peripheral blood lymphocytes <4000/mcL; absence of any new lesion, nodal disease, lymphadenopathy, hepatomegaly, splenomegaly, and constitutional symptoms; neutrophils >1500/mcL, platelets >100000/mcL, hemoglobin >11.0 g/dL without need for transfusion or exogenous growth factors; normocellular bone marrow with <30% lymphocytes; no lymphoid nodules. CRi: fulfilling all CR criteria but persistent cytopenia. PR: >/=50% reduction in two of the following: peripheral blood lymphocytes, lymphadenopathy, spleen and/or liver enlargement; and one of the following: neutrophils >1500/mcL, platelets >100000/mcL, hemoglobin >11.0 g/dL or >/=50% improvement without need for transfusion or exogenous growth factors. nPR: fulfilling all CR criteria but presence of lymphoid nodules. The 95% CI was computed using Pearson-Clopper method.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

Percentage of participants who died from any cause, during the study, was reported. Percentage is rounded off.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

OS was defined as the time from the date of randomization to the date of death from any cause. Participants alive at the time of the analysis were censored at the date when they were last known to be alive as documented by the investigator. The median OS was estimated using Kaplan-Meier method and the 95% CI was computed using method of Brookmeyer and Crowley.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

Percentage of participants with PD/relapse, death from any cause, or start of a new non-protocol-specified anti-CLL therapy as assessed by the investigator, during the study, was reported. PD was defined as occurrence of one of the following events: appearance of any new extra nodal lesion; new palpable lymph node (>1.5 cm); unequivocal progression of non-target lesion; an increase of >/=50% compared to baseline in splenomegaly, hepatomegaly, number of blood lymphocytes with lymphocyte count >/=5000/mcL, or in longest diameter of any extra nodal lesion; transformation to a more aggressive histology; decrease of >/=50% compared to baseline in platelet or neutrophil count; or decrease in hemoglobin level by >2 g/dL or to <10 g/dL. Percentages are rounded off.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

EFS was defined as the time from date of randomization until the date of PD/relapse, start of a new non-protocol-specified anti-CLL therapy, or death from any cause, whichever occurred first, as assessed by the investigator. PD: occurrence of one of the following: new lesion; new palpable lymph node (>1.5 cm); unequivocal progression of non-target lesion; increase of >/=50% in splenomegaly, hepatomegaly, blood lymphocytes with count >/=5000/mcL, longest diameter of any lesion; transformation to more aggressive histology; decrease of >/=50% in platelet or neutrophil count, or hemoglobin level by >2 g/dL or to <10 g/dL. Participants without any of the specified event at the time of analysis were censored at the date of last adequate response assessment. In case of no post-baseline response assessment, participants were censored at the randomization date. The median EFS was estimated using Kaplan-Meier method and the 95% CI was computed using method of Brookmeyer and Crowley.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

Percentage of participants with PD as assessed by the investigator according to the iwCLL guidelines or death from any cause during the study was reported. PD was defined as occurrence of one of the following events: appearance of any new extra nodal lesion; new palpable lymph node (>1.5 cm); unequivocal progression of non-target lesion; an increase of >/=50% compared to baseline in splenomegaly, hepatomegaly, number of blood lymphocytes with lymphocyte count >/=5000/mcL, or in longest diameter of any extra nodal lesion; transformation to a more aggressive histology; decrease of >/=50% compared to baseline in platelet or neutrophil count; or decrease in hemoglobin level by >2 g/dL or to <10 g/dL. CR, CRi, nPR, and PR have been defined in previous outcomes, and are not repeated here due to space constraint. Percentage is rounded off.

Analysis was performed on ITT population participants who had best overall response of CR, CRi, nPR, or PR.

DOR was defined as the time from first occurrence of a documented response of CR, CRi, nPR, or PR until PD/relapse, as assessed by the investigator according to the iwCLL guidelines, or death from any cause. PD: occurrence of one of the following: new lesion; new palpable lymph node (>1.5 cm); unequivocal progression of non-target lesion; increase of >/=50% in splenomegaly, hepatomegaly, blood lymphocytes with count >/=5000/mcL, longest diameter of any lesion; transformation to more aggressive histology; decrease of >/=50% in platelet or neutrophil count, or hemoglobin level by >2 g/dL or to <10 g/dL. Participants without PD or death after response were censored at the last date of adequate response assessment. The median DOR was estimated using Kaplan-Meier method and the 95% CI was computed using method of Brookmeyer and Crowley. CR, CRi, nPR, and PR have been defined in previous outcomes, and are not repeated here due to space constraint.

Analysis was performed on ITT population participants who had best overall response of CR, CRi, nPR, or PR.

Percentage of participants with start of new non-protocol-specified anti-CLL therapy, as assessed by the investigator, or death from any cause, during the study, was reported. Percentage is rounded off.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

TTNT was defined as the time from randomization until start of new non-protocol-specified anti-CLL treatment or death from any cause. Participants without the event at the time of analysis were censored at the last visit date for this outcome measure analysis. The median TTNT was estimated using Kaplan-Meier method and the 95% CI was computed using method of Brookmeyer and Crowley.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

MRD-negativity was defined as the presence of <1 malignant B-cell per 10000 normal B-cells in a sample of at least 200000 B-cells, as assessed by the allele specific oligonucleotide polymerase chain reaction (ASO-PCR) and/or flow cytometry technique. Percentage of participants with MRD-negativity was reported. The 95% CI was computed using Pearson-Clopper method. Percentage is rounded off.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

MRD-negativity was defined as the presence of <1 malignant B-cell per 10000 normal B-cells in a sample of at least 200000 B-cells, as assessed flow cytometry technique. Percentage of participants with MRD-negativity was reported. The 95% CI was computed using Pearson-Clopper method. Percentages are rounded off.

ITT population included all randomized participants, with participants grouped according to randomized treatment group, regardless of the actual treatment received.

Pharmacokinetic (PK) evaluable population included all participants in the 'Venetoclax + Rituximab' arm who received at least one dose of venetoclax with at least one post-dose PK concentration result available. Here 'Number Analyzed' signifies the number of participants evaluable at specified time point.

MDASI is a 25-item validated questionnaire consisting of 2 parts. Part 1: 19-items divided into 2 scales, Core Symptom Severity (average of Questions 1 to 13; total 13 items: pain, fatigue, nausea, disturbed sleep, distress, shortness of breath, remembering things, lack of appetite, drowsiness, dry mouth, sadness, vomiting, and numbness) and Module Symptom Severity (average of Questions 14 to 19; total 6 items: night sweats, fevers and chills, lymph node swelling, diarrhea, bruising easy or bleeding, and constipation). Part 2: 6-items to assess Interference (symptom distress) (average of Questions 20 to 25; total 6 items: general activity, walking, work, mood, relations with other people, and enjoyment of life). Each item was rated from 0 to 10, with lower scores indicating better outcome. Total score for Core Symptom Severity, Module Symptom Severity, and Interference are reported which range from 0 to 10, with lower scores indicating better health-related quality of life (HRQoL).

Patient reported outcomes (PRO) evaluable population included all participants with baseline and at least one post-baseline PRO assessment. Here, 'Overall Number of Participants Analyzed' = participants evaluable for this outcome measure and 'Number Analyzed' = participants evaluable at specified time point.

EORTC QLQ-C30 is a validated self-report measure consisting of 30 questions incorporated into 5 functional scales (Physical, Role, Cognitive, Emotional, and Social), 3 symptom scales (fatigue, pain, nausea, and vomiting), a global health status/global QoL scale, and single items (dyspnea, appetite loss, sleep disturbance, constipation, and diarrhea). Most questions used 4-point scale (1='Not at all' to 4='Very much'), while 2 questions used 7-point scale (1='very poor' to 7='Excellent'). Scores were averaged, transformed to 0-100 scale; where higher score for functional scales=poor level of functioning; higher score for global health status/global QoL=better HRQoL.

Patient reported outcome (PRO) evaluable population included all participants with baseline and at least one post-baseline PRO assessment. Here, 'Overall Number of Participants Analyzed' = participants evaluable for this outcome measure and 'Number Analyzed' = participants evaluable at specified time point.

The EORTC QLQ-CLL16 module is designed for participants with Stage 0 to Stage 4 CLL. It is composed of 16 questions and there are four multi-item scales on Fatigue (2 items), Treatment-related side effects (TRSE, 4 items), Disease-related symptoms (DRS, 4 items), and Infection (4 items); and two single-item scales on social activities and future health worries. Multi-item scales score are reported and the total score for each multi-item scale was transformed to result in a total score range of 0 to 100, where higher score = poor HRQoL.

PRO evaluable population included all participants with baseline and at least one post-baseline PRO assessment. Here, 'Overall Number of Participants Analyzed' = participants evaluable for this outcome measure and 'Number Analyzed' = participants evaluable at specified time point.

An AE was defined as any untoward medical occurrence in a participant administered with Mircera and which does not necessarily have a causal relationship with Mircera. A Serious Adverse Event (SAE) is any significant hazard, contraindication, side effect that is fatal or life threatening; requires in-patient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; is a congenital anomaly/birth defect; is medically significant or requires intervention to prevent one or other of the outcomes listed above. AEs were assessed using National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0 (NCI CTCAE, v4.0)

SE population included all randomized participants who received at least one dose of study treatment with participants grouped according to the actual treatment received.

An AE was defined as any untoward medical occurrence in a participant administered with Mircera and which does not necessarily have a causal relationship with Mircera. A SAE is any significant hazard, contraindication, side effect that is fatal or life threatening; requires in-patient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; is a congenital anomaly/birth defect; is medically significant or requires intervention to prevent one or other of the outcomes listed above. TLS and IRRs were graded using the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE v4.0). Grade 1 = Mild; Grade 2 = Moderate; Grade 3 = Severe or medically significant; Grade 4 = Life-threatening; Grade 5 = Death. A higher grade indicates a worse outcome.

SE population included all randomized participants who received at least one dose of study treatment with participants grouped according to the actual treatment received.