Pertuzumab, trastuzumab, and docetaxel for HER2-positive metastatic breast cancer (CLEOPATRA study): overall survival results from a randomised, double-blind, placebo-controlled, phase 3 study

Abstract

Summary Background Primary results from the randomised, double-blind phase 3 study CLEOPATRA demonstrated significantly improved median progression-free survival (PFS) with pertuzumab plus trastuzumab plus docetaxel versus placebo plus trastuzumab plus docetaxel in patients with human epidermal growth factor receptor 2 (HER2)-positive first-line metastatic breast cancer (MBC). Overall survival (OS) data at the primary analysis showed a strong trend in favour of the pertuzumab arm but did not reach statistical significance. Here we report confirmatory OS results after one additional year of follow-up. Methods Patients were randomly assigned to study treatment. OS and investigator-assessed PFS were analysed using the Kaplan-Meier approach and log-rank tests stratified by geographic region and prior treatment status. This trial is registered with ClinicalTrials.gov, NCT00567190. Findings In the intent-to-treat population (808 patients), 267 deaths had occurred at data cut-off (placebo arm: 154 of 406 [37·9%], pertuzumab arm: 113 of 402 [28·1%]). Treatment with pertuzumab plus trastuzumab plus docetaxel resulted in a 34% reduction in the risk of death during the course of the study (HR=0·66; 95% CI 0·52–0·84; p=0·0008). Median OS was 37·6 months in the placebo arm and was not yet reached in the pertuzumab arm. A descriptive follow-up analysis of investigator-assessed PFS showed a median PFS of 12·4 and 18·7 months in the placebo versus pertuzumab arm (HR=0·69; 95% CI 0·58–0·81). No new safety concerns were identified with one additional year of follow-up. Adverse events were similar to those reported at the primary analysis with respect to incidence, severity, and specificity. Interpretation This OS analysis demonstrated statistically significant and clinically meaningful survival benefit with pertuzumab plus trastuzumab plus docetaxel in patients with HER2-positive MBC. Updated analyses of investigator-assessed PFS and safety were consistent with the results from the primary analysis. Funding F. Hoffmann-La Roche/Genentech

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“…Our data suggest that the ligand-induced homotypic interactions in D5 and D7 are essential for VEGFR activation, providing strategies for the design of specific VEGFR inhibitors for use in combination with current anti-angiogenic inhibitors. Such an approach with two HER2 antibodies has proven successful in the treatment of patients with HER2-positive metastatic breast cancer (41).…”

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