ERBB2 and breast cancer: The primary objective of the study is iDFS.64 Trastuzumab rezetecan is also being evaluated as a neoadjuvant treatment in the prospective, single-arm study (NCT05911958) in patients with early or locally advanced breast cancer who are HR-positive and have low HER2 expression.65 Finally, the same drug is being evaluated in a single-arm, phase II trial (NCT05635487) in combination with pyrotinib maleate, an irreversible inhibitor of HER1, HER2, and HER4 tyrosine kinases.