A Study to Compare the Efficacy and Safety of a Combined Regimen of Venetoclax and Obinutuzumab Versus Fludarabine, Cyclophosphamide, and Rituximab (FCR)/ Bendamustine And Rituximab (BR) in FIT Patients With Previously Untreated Chronic Lymphocytic Leukemia (CLL) Without DEL (17P) or TP53 Mutation

Inclusion Criteria:

* Ability to comply with the study protocol, in the investigator's judgment
* Aged 18 years or older
* Have previously untreated documented Chronic Lymphocytic Leukemia (CLL) according to the International Workshop on Chronic Lymphocytic Leukemia (iwCLL) criteria
* CLL requiring treatment according to the iwCLL criteria
* Cumulative Illness Rating Scale (CIRS) score ≤ 6 and creatinine clearance (CrCl) ≥ 70 mL/min
* Hematology values within the following limits, unless cytopenia is caused by the underlying disease (i.e., no evidence of additional bone marrow (BM) dysfunction; e.g., myelodysplastic syndrome, hypoplastic BM):

  * Absolute neutrophil count ≥ 1.0 x 109/L, unless there is BM involvement
  * Platelet count ≥ 75 x 109/L and more than 7 days since last transfusion, or ≥ 30 x 109/L if there is BM involvement
* Adequate liver function as indicated by a total bilirubin, aspartate aminotransferase, and Alanine transaminase ≤ 2 times the institutional upper limit of normal (ULN) value, unless directly attributable to the participant's CLL
* Life expectancy \>6 months
* For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraception and agreement to refrain from donating eggs
* For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive methods, and agreement to refrain from donating sperm

Exclusion Criteria:

* Transformation of CLL to aggressive Non-Hodgkin's Lymphoma (NHL)
* Participants with Small Lymphocyclic Lymphoma (SLL) only
* Known central nervous system involvement
* Participants with a history of confirmed progressive multifocal leukoencephalopathy (PML)
* Detected del(17p) or TP53 mutation (valid test within 6-months from screening is required for randomisation)
* An individual organ/system impairment score of 4 as assessed by the Cumulative Illness Rating Scale (CIRS) definition limiting the ability to receive the treatment regimen of this trial with the exception of eyes, ears, nose, throat organ system
* Participants with uncontrolled autoimmune hemolytic anemia or immune thrombocytopenia
* History of prior malignancy
* Participants with infections requiring IV treatment (Grade 3 or 4) within the last 8 weeks prior to enrollment
* Evidence of other clinically significant uncontrolled conditions including but not limited to active or uncontrolled systemic infection (e.g., viral, bacterial, or fungal)
* History of severe allergic or anaphylactic reactions to humanized or murine monoclonal antibodies or known sensitivity or allergy to murine products
* Hypersensitivity to fludarabine, bendamustine, cyclophosphamide, rituximab, obinutuzumab, or venetoclax or to any of the excipients (e.g., trehalose)
* Pregnant women and nursing mothers
* Vaccination with a live vaccine ≤ 28 days prior to randomization
* Prisoners or participants who are institutionalized by regulatory or court order or persons who are in dependence to the Sponsor or an investigator
* History of illicit drug or alcohol abuse within 12 months prior to screening, in the investigator's judgment
* Positive test results for chronic hepatitis B virus (HBV) infection (defined as positive hepatitis B surface antigen \[HBsAg\] serology)
* Positive test result for hepatitis C (hepatitis C virus \[HCV\] antibody serology testing)
* Participants with known infection with HIV or Human T-Cell Leukemia Virus 1 (HTLV-1)
* Any serious medical condition or abnormality in clinical laboratory tests that, in the investigator's judgment, precludes the participant's safe participation in and completion of the study
* Received any of the following agents within 28 days prior to the first dose of study treatment:

  * Immunotherapy
  * Radiotherapy
  * Hormone therapy
  * Any therapies intended for the treatment of lymphoma/leukemia whether approved or experimental
* Participants who have received the following agents:

  * Strong and moderate CYP3A inhibitors/inducers within 7 days prior to the initiation of study treatment
  * Steroid therapy for anti-neoplastic intent with the exception of inhaled steroids for asthma, topical steroids, or replacement/stress corticosteroids within 7 days prior to the first dose of study drug administration
  * Consumed grapefruit, grapefruit products, Seville oranges(including marmalade containing Seville oranges), or star fruit within 3 days prior to the first dose of study drug and throughout venetoclax administration
* Inability to swallow a large number of tablets.