The HER2CLIMB-05 study is a phase III clinical study. phase II trial that investigated the benefit of adding tucatinib to first-line maintenance trastuzumab and pertuzumab in patients with HER2-positive metastatic breast cancer.[1] The addition of tucatinib delayed disease progression and potentially extended chemotherapy-free time.[1] The primary analysis of investigator-assessed progression-free progression was statistically significant and showed a benefit of 8.6 months.[1] In the subgroup with HR-negative tumors, the benefit was more than 12 months, highly statistically significant.[1] In the subgroup with HR-positive tumors, the benefit was 6.9 months, also statistically significant.[1] The results were presented at the San Antonio Breast Cancer Symposium (SABCS) 2025.[1]