Inclusion Criteria:

          -  Age ≥ 18 years.

          -  Any menopausal status. If pre-/perimenopausal, agreement to receive LHRH agonist
             (goserelin or leuprorelin) / ovarian ablation in case of randomization to arm A

          -  Locally confirmed diagnosis of metastatic adenocarcinoma of the breast without prior
             systemic antineoplastic therapy in the palliative setting.

          -  Hormone receptor (HR)-positive disease, defined as estrogen receptor (ER)-positive
             and/or progesterone receptor (PgR)-positive.

          -  Human epidermal growth factor receptor 2 (HER2)-negative disease (defined as
             immunohistochemistry (IHC) status HER2 negative/+ or IHC HER2++ with chromosomal in
             situ hybridization (CISH)/fluorescent in situ hybridization (FISH) negative).

          -  Presence of visceral metastases (additional non-visceral metastases are allowed).

          -  Presence of target and / or non-target lesions according to RECIST v1.1

          -  Patients eligible for palliative treatment with AI / fulvestrant + ribociclib and
             capecitabine + bevacizumab or paclitaxel + / - bevacizumab according to the respective
             SmPCs.

          -  Eastern Cooperative Oncology Group (ECOG) performance status 0-1.

          -  Adequate organ and bone marrow function within 7 days prior to randomization.

          -  Standard 12-lead ECG values: QT Interval Corrected by the Fridericia Correction
             Formula (QTcF) interval at screening < 450 msec; Mean resting heart rate 50-90 bpm
             (determined from the ECG)

          -  Signed written informed consent prior to beginning of protocol-specific procedures.

        Exclusion Criteria:

          -  Any prior systemic palliative therapy

          -  Prior treatment with any cyclin-dependent kinase 4/6 (CDK4/6) inhibitor.

          -  Prior adjuvant or neoadjuvant taxane therapy if last application within 12 months
             prior to entering the study.

          -  Patient is concurrently using other anti-cancer therapy.

          -  Patient has had major surgery within 28 days prior to randomization or has not
             recovered from major side effects or wound is not fully recovered.

          -  Patient has received extended-field radiotherapy ≤ 4 weeks or limited-field
             radiotherapy ≤ 2 weeks prior to randomization.

          -  Known hypersensitivity to ribociclib, AI, paclitaxel, bevacizumab or any of their
             excipients, or against peanut, soya, Chinese hamster ovarian cell products or
             macrogolglycerol ricinoleate-35.

          -  Clinically significant, uncontrolled heart disease and/or cardiac repolarization
             abnormality (e.g. history of myocardial infarction within 6 months prior study entry,
             long QT syndrome, clinically significant cardiac arrhythmias or systolic blood
             pressure > 140 or < 90 mmHg or diastolic blood pressure > 90 mmHg).

          -  Patient has history of arterial thrombosis within 12 months prior to entering the
             study.

          -  Patient has proteinuria (≥ 2+ on urine dipstick)

          -  Patient with congenital bleeding diathesis, acquired coagulopathy or under full dose
             of anticoagulants.

          -  Patient is currently receiving strong inducers or inhibitors of CYP3A4/5 or medication
             with narrow therapeutic window that are predominantly metabolized through CYP3A4/5 and
             cannot be discontinued 7 days prior to start of study treatment.

          -  Known presence of cerebral metastases unless at least 4 weeks from prior therapy
             completion (including radiation and/or surgery) to starting the study treatment and
             clinically stable central nervous system tumor at the time of screening.

          -  Patient is currently receiving warfarin or other coumarin derived anti-coagulant, for
             treatment, prophylaxis or otherwise. Therapy with heparin, low molecular weight
             heparin (LMWH), or fondaparinux is allowed.

          -  Patient is currently receiving or has received systemic corticosteroids or other
             chronic immunosuppressive therapy ≤ 2 weeks prior to starting study drug.

          -  Patients with advanced symptomatic, visceral spread, that are at risk of
             lifethreatening complications in the short term (including patients with massive
             uncontrolled effusions [pleural, pericardial, peritoneal], pulmonary lymphangitis, and
             over 50% liver involvement).

          -  Patient has a known history of HIV infection (testing not mandatory).

          -  Patient has active untreated or uncontrolled fungal, bacterial or viral infection.

          -  Patient has any other concurrent severe and/or uncontrolled medical condition that
             would, in the investigator's judgment, cause unacceptable safety risks, contraindicate
             patient participation in the clinical study or compromise compliance with the protocol
             (e.g. chronic pancreatitis, chronic active hepatitis, etc.).

          -  Participation in prior investigational studies within 30 days prior to randomization
             or within 5-half lives of the investigational product, whichever is longer.