Pertuzumab in Combination with Trastuzumab and Docetaxel in the Neoadjuvant Treatment for HER2-Positive Breast Cancer

INTRODUCTION: This study aims to assess safety and effectiveness of pertuzumab in combination with trastuzumab and docetaxel in the neoadjuvant treatment (NeoT) of HER2-positive breast cancer. METHODS: Two consecutive retrospective cohorts (n = 94, 2012–2015 and 2015–2017) of adult women with HER2-positive breast cancer, receiving NeoT at the breast clinic in Portugal (IPO-Porto), were followed. All patients had surgery and received trastuzumab as adjuvant therapy. The 2012–2015 cohort received doxorubicin, cyclophosphamide, docetaxel plus trastuzumab, whereas the 2015–2017 cohort was treated with the same protocol plus pertuzumab. RESULTS: The 2012–2015 cohort was older (median 53 years), with locally advanced tumors (48.1%), mostly hormone receptor positive (59.3%). The 2015–2017 cohort was younger (median 43 years) with 60% operable tumors. Pathologic complete response (pCR) improved in the second cohort, while maintaining a good safety profile and tolerability. Clinical staging (p = 0.001) and hormone receptor (p = 0.003) were significant predictors of pCR, but not treatment regimen (p = 0.304). CONCLUSION: Further research with larger samples and longer follow-up is needed to understand the clinical differences. Clinical effectiveness of treatment should also be measured through overall and progression-free survival.