The results of the phase 3, randomized, open-label KAITLIN study (NCT01966471) showed that T-DM1 + P (18 cycles) was not superior to the standard taxane + trastuzumab + pertuzumab (THP) regimen (three or four cycles), each administered after three or four cycles of anthracycline-based chemotherapy, when used as adjuvant therapy in the treatment of high-risk HER2-positive early stage breast cancer [11]. The gene discussed is ERBB2; the disease is breast cancer.