eMonarcHER: A Randomized, Double Blind, Placebo-Controlled Phase 3 Study of Abemaciclib plus Standard Adjuvant Endocrine Therapy in Participants with High-Risk, Node-Positive, HR+, HER2+ Early Breast Cancer Who Have Completed Adjuvant HER2-Targeted Therapy

• Must have confirmed HR+, HER2+ lymph node positive early invasive breast cancer 
• Must have undergone definitive surgery of the primary breast tumor
• Must have receievd a minimum of 4 cycles of chemotherapy either in neoadjuvant or adjuvant setting
• Must have completed 9 months to 1 year of followingadjuvant HER2-targeted therapy
  • For those treated with neoadjuvant chemo/HER2, must have received T-DM1 in adjuvant setting 
  • For those not-treated with neoadjuvant chemo/HER2, must have received adjuvant pertuzumab + trastuzumab
• Must have completed adjuvant HER2 therapy within 12 weeks of randomization
• High risk disease defined as follows:
  • Neoadjuvant patients must have positive axillary node at time of surgery
  • Non-neoadjuvant patients must either have
    • 4 or more positive lymph nodes at surgery
    • 1-3 positive lymph nodes with either
      • Grade 3 disease or
      • Tumor size 5 cm or greater
• No inflammatory breast cancer
• No prior invasive breast cancer including most DCIS/LCIS
• No history of VTE
• No prior CDK4/6 agents
• No prior neratinib, tucatinib, trastuzumab deruxtecan, or investigational HER2 therapy
• No history of tamoxifen or AI for primary prevention

• Primary
  • Invasive disease free survival
• Secondary
  • OS
  • Distant relapse free survival
  • PRO measures
  • PK