The HER2CLIMB trial demonstrated that the combination of tucatinib, capecitabine, and trastuzumab achieved a central nervous system overall response rate (CNS-ORR) of 47.3% and a median CNS progression-free survival (PFS) of 9.6 months in patients with active BrMs,8 establishing this triplet as an effective systemic therapy for HER2-positive breast cancer patients with active BrMs after prior treatment. The gene discussed is ERBB2; the disease is breast cancer.