Interchangeability of Trastuzumab biosimilars in the neoadjuvante treatment of breast cancer: A real-life study

Abstract

 Introduction: Trastuzumab (T) is incorporated into Brazil’s Public Health System (SUS) for the first-line treatment of HER 2 - positive breast cancer (CaM). The interchangeability (IC) between a comparator product and a biosimilar (BS) is a controversial topic. Post-marketing studies are needed to ensure safety and efficacy in IC situations. Objective: To evaluate whether IC between different manufacturers of T BS interferes with the rate of pathological complete response (PCR) in the neoadjuvant treatment of HER 2 – positive CaM. Methods: The clinical data of patients diagnosed with CaM, HER 2 – positive, clinical stage III, between 2020 and 2022 were reviewed. These patients received neoadjuvant treatment based on chemotherapy plus T, via SUS at an Oncology Hospital located in southern Brazil. Results: Between 2020 and 2022, SUS made 4 different T manufacturers available. 138 patients were eligible for analysis. 78 patients received only one type of T compound (Non-interchangeability Group – GNIC) and 60 patients received at least 2 different T compounds. Both groups were clinically comparable (age, histological profile, tumor size and lymph node staging and axillary). The IC rate over time was 11%, 53%, and 33% in 2020, 2021, and 2022, respectively. The PCR was 33.33% in GNIC versus 33.33% in GCI. Both groups were comparable in terms of incidence of myelotoxicity, infusion reactions and cardiotoxicity. Conclusion: The present study demonstrated that the IC between BS of T did not interfere in a statistically significant way in the PCR.