Key clinical point: In the real-world setting, the overall survival (OS) with pertuzumab and trastuzumab emtansine (T-DM1) in patients with human epidermal growth factor hormone receptor 2 (HER2)-positive metastatic breast cancer is inferior to results from pivotal clinical trials.
Major finding: The OS with pertuzumab and T-DM1 was shorter than that reported in the pivotal clinical trials. In the pertuzumab cohort, OS was 43 months and time on treatment was 14 months. In the T-DM1 cohort, median OS and time on treatment were 15 months and 4 months, respectively.
Study details: A population-based retrospective cohort study of patients with ERBB2-positive metastatic breast cancer treated with first-line pertuzumab (n=795) or second-line T-DM1 (n=506).
Disclosures: This study was supported by the Canadian Institutes of Health Research. The authors received personal fees from various sources outside this work. Dr. CM Booth was supported as a Canada Research Chair in Population Cancer Care.
Source: Ethier JL et al. JAMA Oncol. 2021 Jul 8. doi: 10.1001/jamaoncol.2021.2140 .