neoPEHP is a multicohort, open-label, exploratory, phase 2 study. Patients were eligible if they had previously untreated, histologically confirmed, unilateral, invasive, HER2-positive, ER-positive breast cancer and were suitable for neoadjuvant therapy. Patients were treated every 3 weeks with intravenous trastuzumab (8 mg/kg loading dose followed by 6 mg/kg) and oral pyrotinib (400 mg po QD) for six cycles plus oral palbociclib (125 mg once a day for 21 days in a 4-week cycle) and oral exemestane (25 mg po QD) every 4 weeks for 24 weeks. The primary endpoints was pathological complete response.

Inclusion Criteria:

• We judged patients eligible for the first study cohort if they had previously untreated, histologically confirmed, unilateral, invasive, HER2-positive (3+ on immunohistochemistry or neu-amplified) and ER-positive (>10% of cells in the tumour expressing ER) breast cancer. Other inclusion criteria were age 18 years or older, Eastern Cooperative Oncology Group (ECOG) performance status of 1 or less, and tumour classified between cT1c and cT4a-d.

Exclusion Criteria:

• metastatic disease, bilateral breast cancer, other malignant disease, inadequate bone marrow or renal function, impaired liver function, impaired cardiac function, uncontrolled hypertension, pregnancy, and refusal to use contraception.