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

Resumo

Introduction: Trastuzumab (Trt) is incorporated into Brazil’s Public Health System (SUS)
for the first-line treatment of HER 2 - positive breast cancer (CaM). The interchangea
bility (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. Objec
tive: To evaluate whether IC between different manufacturers of Trt 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 Trt, via SUS at an Onco
logy Hospital located in southern Brazil. Results: Between 2020 and 2022, SUS made
4 different Trt manufacturers available. one hundred thirty-eight (138) patients were
eligible for analysis. Seventy eight (78) patients received only one type of Trt compound
(Non-interchangeability Group – GNIC) and 60 patients received at least 2 different Trt
compounds (Interchangeability Group – GCI). 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 Trt did not interfere in a statistically sig
nificant way in the RPC.