Methods
This multicenter, phase I study followed a standard “3 + 3” design and included two parts. In the pyrotinib part, pyrotinib was administered orally, once per day at dose levels of 240, 320, 400, and 480 mg. In the pyrotinib plus docetaxel part, patients received pyrotinib (qd, d1‐21, q3W) combined with docetaxel (60 mg/m