Patients receiving a lower dose of 5.4 mg/kg, which is the same as the recommended and approved dosage in HER2-positive breast cancer, had an ORR, median PFS, and median OS of 49.0%, 9.9 months, and 19.5 months, respectively, while those on 6.4 mg/kg showed an ORR and median PFS of 56.0% and 15.4 months, respectively [81] (Table 8). The gene discussed is ERBB2; the disease is breast cancer.