The Impact of Initial Tumor Response on Survival Outcomes of Patients With HER2-Positive Advanced Breast Cancer Treated With Docetaxel, Trastuzumab, and Pertuzumab: An Exploratory Analysis of the CLEOPATRA Trial

The CLEOPATRA trial (NCT00567190) established a dual anti-HER2 blockade in combination with docetaxel as the first-line standard of care for patients with metastatic HER2-positive breast cancer. While this treatment is overall associated with significant improvement in progression-free survival (PFS) and overall survival (OS), not all patients respond equally. We hypothesized that a radiological complete response (CR) at week 9 (i.e., first disease re-evaluation) is associated with prolonged OS and PFS compared to radiological partial response (PR) or stable disease (SD).