Pertuzumab, trastuzumab, and docetaxel for Chinese patients with previously untreated HER2-positive locally recurrent or metastatic breast cancer (PUFFIN): final analysis of a phase III, randomized, double-blind, placebo-controlled study

Purpose: PUFFIN (NCT02896855), a Chinese bridging study in patients with previously untreated HER2-positive locally recurrent or metastatic breast cancer, assessed consistency of efficacy and safety of pertuzumab plus trastuzumab and docetaxel versus placebo, trastuzumab, and docetaxel, with CLEOPATRA (NCT00567190). Methods: Eligible patients, n = 243, were randomized 1:1, stratified by visceral disease and hormone receptor status, to pertuzumab, trastuzumab, and docetaxel or placebo, trastuzumab, and docetaxel. Primary endpoint: investigator-assessed progression-free survival (PFS). Secondary endpoints: safety and overall survival (OS). After primary analysis, patients could cross over to the pertuzumab arm. Results: Updated median PFS: 16.5 months (pertuzumab arm) and 12.5 months (placebo arm), with a hazard ratio (HR) of 0.60 [95% confidence interval (CI) 0.45, 0.81; p = 0.0008]. Median OS was not reached in either arm; the OS HR was 0.68 (95% CI 0.45, 1.03; p = 0.0658). Safety was similar in both arms with no new safety signals: 73.8% (pertuzumab arm) and 69.2% (placebo arm) experienced grade ≥ 3 adverse events. No heart failure, symptomatic left ventricular systolic dysfunction, or left ventricular ejection fraction decline of < 40% were reported. Conclusions: The PUFFIN final analysis showed, per the primary analysis, that overall efficacy of pertuzumab plus trastuzumab and docetaxel was consistent with CLEOPATRA. Safety remained consistent with the known pertuzumab profile. Overall, PUFFIN contributes to the totality of data with pertuzumab in previously untreated HER2-positive locally recurrent or metastatic breast cancer and supports the favorable benefit–risk profile of pertuzumab in Chinese patients. Trial registration: ClinicalTrials.gov, NCT02896855, registered 7 September 2016.