Adjuvant WIDER: This study is recruiting people with HR+, HER2- early breast cancer to investigate how safe and effective treatment with a combination of targeted and hormone therapy isA Phase IIIb Study to Characterize the Effectiveness and Safety of Adjuvant Ribociclib in a Wide Patient Population With HR+ HER2- Early Breast Cancer (Adjuvant WIDER)

Inclusion

• Participant has a histologically and/or cytologically confirmed diagnosis of estrogen-receptor positive and/or progesterone receptor positive breast cancer
• Participant has HER2-negative breast cancer
• Participants may have already received any standard neoadjuvant and/or adjuvant ET, including tamoxifen or toremifene, at the time of informed consent signature, but enrollment should occur within 36 months of prior ET start date and the participant should have at least 3 years remaining of endocrine adjuvant therapy. For participants with prior ET treatment > 12 months, the investigator should rule out disease recurrence prior to enrollment. The number of participants with prior ET between 12 and 36 months will be capped at 1000.
• Participant has no contraindication for the adjuvant ET in the study.

• Participant after complete surgical resection with the final surgical specimen microscopic margins free from tumor and in one of below categories:

  • Anatomic Stage Group III
  • Anatomic Stage Group II (subset)
  • Anatomic Stage Group I (high-risk subset as exploratory cohort)
• Participant has an Eastern Cooperative Oncology Group (ECOG) Performance Status of 0,1 or 2.
• Participant has adequate bone marrow and organ function.