Fig. 1

Study schema for the NeoPalAna trial. Eligible patients with clinical stage II-III ER+/HER2− breast cancer received anastrozole monotherapy for 28 days in cycle 0, followed by addition of palbociclib on cycle 1, day 1 (C1D1), for four 28-day cycles unless C1D15 Ki-67 was > 10%. Breast surgery occurred after a washout of 3–5 weeks of palbociclib while the patient was continued on anastrozole, except for eight patients who also received cycle 5 of palbociclib immediately prior to surgery. Serial tumor biopsies and blood collections occurred at baseline, C1D1, C1D15, and time of surgery