Purpose: Improving the outcome of patients with HER2-negative metastatic breast cancer experiencing tumour progression following first-line chemotherapy remains an urgent medical need. The purpose of the VicTORia trial was to show superiority of everolimus in combination with vinorelbine versus vinorelbine monotherapy as second-line chemotherapy for patients with advanced HER2 negative breast cancer.
Methods: In this randomised phase II trial, 133 patients were recruited in 32 centres in Germany. Patients were randomised 1:1 to second-line chemotherapy either with vinorelbine plus everolimus (arm1) or vinorelbine alone (arm2). Primary endpoint was progression-free survival (PFS). Secondary endpoints were PFS rate at 6 months, overall survival (OS), overall response rate (ORR) and safety. Baseline PI3 K mutational status was determined in plasma samples.
Results: Median progression-free survival was not different between arms (arm1 vs. arm2: 4.01 months, 95% CI 2.40-6.09 vs. 4.08, 95% CI 2.80-5.33). PFS rate at 6 months (arm1 vs. arm2: 39.4%, 95% CI 27.6-50.9% vs. 36.6%, 95% CI 24.6-48.6%), median OS (arm1 vs. arm2: 16.3 months, 95% CI 11.4-19.0 vs. 13.8 months, 95% CI 10.2-19.1) and ORR were not different between arms. Most frequent grade 3/4 adverse events were neutropenia (50% vs. 40%), gastrointestinal toxicities (19.1% vs. 6.1%), and infections (19.1% vs. 7.7%). PI3 K mutational status was neither associated with PFS nor with OS.
Conclusion: Although well tolerated, the efficacy of everolimus and vinorelbine combination therapy was not superior to vinorelbine monotherapy. There was no correlation between PI3 K mutational status and efficacy. EudracCT No 2011-001024-38, ClinicalTrials.gov No NCT01520103.
Keywords: Everolimus; HER2 negative; Metastatic breast cancer; Second-line treatment; Vinorelbine.