A Multicenter Chart Review Study for Evaluating The Efficacy and Safety of Neoadjuvant Trastuzumab Plus Taxane With and Without Pertuzumab Therapy in Locally Advanced HER2 Positive Breast Cancer Patients

In 2013, the Food and Drug Agency (FDA) granted accelerated approval to pertuzumab for use in the neoadjuvant setting with trastuzumab and chemotherapy for HER2+ locally advanced breast cancer (either greater than 2 cm in diameter or node positive), based on improvement in pCR in the NeoSphere (Neoadjuvant Study of Pertuzumab and Herceptin in an Early Regimen Evaluation) and TRYPHAENA (Trastuzumab plus Pertuzumab in Neoadjuvant HER2- positive Breast Cancer) studies. Full approval of pertuzumab in the early stage for patients at high risk of recurrence was recently received based on results of the adjuvant APHINITY study. NeoSphere study demonstrated a higher breast pCR rate with THP 17 (docetaxel, trastuzumab, pertuzumab) as compared to TH (breast pCR 45.8 versus 29%), and TRYPHAENA study also demonstrated high total pCR rates with FEC (5- fluorouracil, epirubicin, and cyclophosphamide)-THP (pCR 54.7%) and TCHP (docetaxel, carboplatin, HP, pCR 63.6%).

Pertuzumab is a humanized monoclonal antibody and is the first of a novel class of HER2-targeted agents known as HER2 dimerization inhibitors. This agent bind to a distinct epitope on the extracellular domain of the HER2 receptor (the domain II dimerization arm), blocking the interaction between HER2 and other HER family receptors. Potent inhibition of HER-mediated intracellular signaling results in cancer cell growth inhibition and death.

In Turkey, Pertuzumab has been authorized as neoadjuvant therapy for breast cancer patients since March 2019. Before this date pertuzumab was also available after patient- based approvals. Due to lack of local data regarding outcomes of pertuzumab in neoadjuvant therapy for breast cancer patients, this study will be the first in this area, in terms of national real world data.

This study is a Non-Interventional Study (NIS) with secondary data usage. It is designed as a multi-center retrospective cohort study in which the data of adult breast cancer patients, who are treated with as neoadjuvant therapy and underwent breast surgery in participating centers, were taken from hospital records.

NIS secondary data use based on electronic health records and paper files. Required key, primary and secondary variables will be ready including pCR data at the hospital records. If not, at the time of surgery there will be biopsy / imaging and other laboratory results, so primary or sub-investigator could also assess response and note as a source document.