e13023 Background: Real-World Evidence (RWE) are gain importance once they are designed to evaluate the effectiveness of drugs whose efficacy has already been demonstrated in randomized controlled trials. In 2017, Brazil approved the first biosimilar of trastuzumab for treatment of breast cancer (BC) with overexpression of HER2. The anti-HER2 treatment significantly improves outcome in patients with HER2-positive BC. Trastuzumab-dkst is clinically effective biosimilar and help to increase access to BC treatment. The aim of this RWE is to address the effectiveness of adjuvant biosimilar trastuzumab-dkst in Brazilian women with early HER2+ BC. Methods: This is a national, multicenter, observational, prospective, RWE study conducted in Brazilian institutions. A hundred and seventy female adult patients, with diagnosis of early stage HER2-positive BC, who received at least one dose of trastuzumab-dkst as adjuvant therapy will be included. The follow-up period will be 5 years after the first dose of trastuzumab-dkst, unless tumor recurrence or death. The safety endpoints are the occurrence adverse events. The effectiveness endpoints are invasive disease relapse-free survival rate at 18, 24, 30 and 36 months after the start of biosimilar use, the invasive disease relapse-free survival after curative-intent surgery and overall survival after curative intent surgery. Given the inexistence of a specific hypothesis to be tested, sample size was based on the accuracy of the two-sided 95% confidence interval (95% CI) for the invasive disease relapse-free survival rate. Results: The recruitment planning covered 21 sites across the five regions of Brazil: North, Northeast, Midwest, Southeast, and South. From those 21 sites, 14 ( > 50%) have already been approved by their local ethical committee for patient recruitment. At 7 months, we have enrolled 50 patients over the five Brazilian regions, which means 29.4% of the total. Conclusions: To conduct RWE in Brazil is still challenging and we have listed 5 possible reasons: (1) there are few RWE studies running in the country, (2) we do not have trialists experienced in RWE design; (3) low medical commitment to adverse event report in RWE; (4) low budget for RWE; (5) slow ethics and regulatory process approval in Brazil. Considering the pioneering and challenges to develop the RWE in Brazil, we are achieving optimum adherence from medical sites. Moreover, roughly one quarter of the target recruitment was reached in the first 7 months after the study start date. Clinical trial information: NCT03892655 .
Real-world data of subcutaneous trastuzumab and intravenous pertuzumab as neoadjuvant therapy for localized HER2+ breast cancer in Panama
