Efficacy and Safety of the use of Pertuzumab in Metastatic Breast Cancer Patients in a Real-World Setting: Results from the SUPER-GONO (Gruppo Oncologico del Nord Ovest) Study

Abstract Background: Real world data have the potential to demonstrate the applicability of the results of randomized studies in the general population. SUPER trial was conducted in order to assess the activity, the efficacy and the safety of the combination of pertuzumab, trastuzumab and chemotherapy in clinical practice.Material and methods: Patients diagnosed with HER2 positive metastatic breast cancer (mBC) and treated with pertuzumab, trastuzumab and chemotherapy were accrued at 18 italian hospitals. Data were retrospectively collected in the time frame between pertuzumab availability in clinical practice and study approval in 2016, and prospectively collected thereafter. Results: Overall 342 HER2 positive mBC were accrued. 172 patients had relapsed disease and 56.4% of them received neo/adjuvant trastuzumab. 205 patients received docetaxel. Objective response rate was 76.3% (95%CI: 71.4–80.7). Median progression free survival (PFS) and overall survival (OS) were 24.3 months (95% CI: 20.0–28.9) and 70.2 months (95% CI: 61.4–79.0) respectively. Triple positive patients treated with endocrine therapy in addition to pertuzumab and trastuzumab maintenance had a significant longer PFS and OS than patients who did not. mPFS was 31.2 months and 13 months respectively (HR=0.47; 95% CI: 0.33–0.66; p<0.001) and mOS was 72.3 months and 56.8 months respectively (HR=0.58; 95% CI: 0.36–0.92; p=0.02). Pretreatment with trastuzumab did not hamper the outcome. In addition, maintaining the dual blockade inhibition at disease progression with the same CT partner or alternative endocrine agent leading to further benefit.Conclusions: SUPER suggests that results of first-line treatment with pertuzumab, trastuzumab and chemotherapy in unselected patients are consistent with findings from CLEOPATRA trial.Moreover, as expected from real world evidence, new insights have emerged.