A. Jo Chien, Kevin M Kalinsky, Julissa Molina-Vega, Rita Mukhtar, Karthik Giridhar, Olufunmilayo I Olopade, Amrita Basu, Smita M Asare, Paul Henderson, Gillian Hirst, Ruixiao Lu, Ella Jones, Nola Hylton, Lamorna Brown-Swigart, Laura J van 't Veer, Douglas Yee, Ingrid Mayer, Laura J Esserman. Abstract OT1-10-02: I-SPY2 endocrine optimization protocol (EOP): A pilot neoadjuvant endocrine therapy study with amcenestrant as monotherapy or in combination with abemacicilib or letrozole in molecularly selected HR+/HER2- clinical stage 2/3 breast cancer. Cancer Research. 2022 Feb 15; 82(4_Supplement):ot1-10-02-ot1-10-02.