Objective To assess the efficacy and safety of pyrotinib (an irreversible pan-HER (human epidermal growth factor receptor) inhibitor), trastuzumab, and docetaxel compared with placebo, trastuzumab, and docetaxel for untreated HER2 positive metastatic breast cancer.
Design Randomised, double blind, placebo controlled, multicentre, phase 3 trial.
Setting 40 centres in China between 6 May 2019 and 17 January 2022.
Participants 590 female patients (median age 52 (interquartile range 46-58) years) with untreated HER2 positive metastatic breast cancer.
Interventions Eligible patients were randomised 1:1 to receive either oral pyrotinib (400 mg once daily) or placebo, both combined with intravenous trastuzumab (8 mg/kg in cycle 1 and 6 mg/kg in subsequent cycles) and docetaxel (75 mg/m2) on day 1 of each 21 day cycle. Randomisation was stratified by treatment history of trastuzumab in the (neo)adjuvant setting and hormone receptor status. Patients, investigators, and the sponsor’s study