e-Poster Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2020

Abemaciclib combined with endocrine therapy for the adjuvant treatment of high-risk early breast cancer. (#210)

Stephen R D Johnston 1 , Nadia Harbeck 2 , Roberto Hegg 3 , Mazakazu Toi 4 , Miguel Martin 5 , Zhimin Shao 6 , Mario Campone 7 , Erika Hamilton 8 , Joohyuk Sohn 9 , Valentina Guarneri 10 , Javier Cortes 11 , Patrick Neven 12 , Frances Boyle 13 , Ian C Smith 14 , Martin Frenzel 14 , Desiree Headley 14 , Ran Wei 14 , Joanne Cox 14 , Joyce O'Shaughnessy 15 , Priya Rastogi 16
  1. Royal Marsden NHS Foundation Trust, London, UK
  2. Breast Center, Dept OB&GYN, LMU University Hospital, Munich, Germany
  3. Clinica Pesquisas e Centro São Paulo, , São Paulo, Brazil
  4. Kyoto University Hospital, Kyoto, Japan
  5. Hospital General Universitario Gregorio Marañon, Universidad Complutense, Ciberonc, Madrid, Spain
  6. Shanghai Cancer Center, Fudan University, Shanghai, China
  7. Institut de Cancérologie de l’Ouest , Pays de la Loire Saint Herblain-Angers, France
  8. Sarah Cannon Research Institute/Tennessee Oncology, Nashville, TN, USA
  9. Yonsei Cancer Center, Seoul, Korea
  10. Department of Surgery, Oncology and Gastroenterology, Istituto Oncologico Veneto IOV IRCCS, University of Padova, Padova, Italy
  11. IOB institute of Oncology, Quiron Group, Madrid & Barcelona & Vall d´Hebron Institute of Oncology, Barcelona, Spain
  12. Universitaire Ziekenhuizen Leuven, Campus Gasthuisberg, Leuven, Belgium
  13. Patricia Ritchie Centre for Cancer Care and Research, Mater Hospital Sydney, North Sydney , NSW, Australia
  14. Eli Lilly and Company, Indianapolis, IN, USA
  15. Oncology , Baylor University Medical Center, Dallas, TX, USA
  16. NSABP Foundation, University of Pittsburgh, Pittsburgh, PA, USA

Background  

Approximately 90% of patients with breast cancer are diagnosed with early breast cancer (EBC) and ~30% with HR+ disease experience distant relapse. Historical data estimate the 5-year invasive disease-free survival (IDFS) rate for the population at high-risk of recurrence based on clinicopathological features and high Ki-67 to be between 80% and 85% following completion of definitive locoregional therapy and chemotherapy. Abemaciclib is an oral, continuously dosed CDK4 & 6 inhibitor approved for use in HR+, HER2- advanced breast cancer. The efficacy and safety of abemaciclib in the metastatic setting supported Phase 3 evaluation in the adjuvant setting.

Methods  

This open-label phase 3 study randomized (1:1) 5,637 patients with node-positive (N+), HR+, HER2-, high-risk EBC to standard of care (SOC) adjuvant endocrine therapy (ET) with or without abemaciclib (150 mg BID for 2 years). Women and men with ≥4 positive nodes, or 1-3 nodes and at least one of the following features: grade 3 disease, tumor size ≥5 cm, and/or central Ki-67 ≥20%, were eligible. The primary endpoint was IDFS per STEEP criteria and key secondary endpoints included distant recurrence-free survival, overall survival and safety. A preplanned efficacy interim analysis occurred after approximately 293 IDFS events. 

Expected Results  

The results of this efficacy interim analysis will be presented at the ESMO meeting September 2020 and published simultaneously.  

Expected Conclusions  

Following the efficacy interim analysis, the associated conclusions will be presented at the meeting.

ClinicalTrials.gov: NCT03155997