ERBB2 and breast cancer: Indeed, T-DM1 (trastuzumab emtansine) and T-DXd were initially approved only for HER-2 positive breast cancer patients,180 however, in the DESTINY-Lung01 trial, only NSCLC patients with HER-2 mutations, rather than those with HER-2 amplification or overexpression, showed significant benefit, leading to the accelerated approval by FDA.181