Real World Study of Biosimilar Trastuzumab in Her2 Positive Breast Cancer
Real World Study of Biosimilar Trastuzumab in Her2 Positive Breast Cancer
Zedora registration was based on studies of women with metastatic breast cancer, but its
 approval includes adjuvant treatment. Thus, prospective data of drug use in localized disease
 are lacking, as well as are real-world safety and efficacy data, taking into consideration
 comorbidities and compliance difficulties.

 This will be an observational study of patients receiving adjuvant Zedora at several
 Brazilian institutions for the purpose of describing its efficacy and safety.
An observational, multicenter, prospective, real-world study at Brazilian institutions.

 Adult patients with early HER2+ breast cancer receiving adjuvant biosimilar trastuzumab
 (Zedora) at the participating sites after the start of the study and meeting the eligibility
 criteria will be invited to participate. Demographics, comorbidities, disease history, extent
 of exposure to biosimilar trastuzumab (Zedora), adverse events and LVEF values will be
 collected.

 Data collection will be performed using a case report form (CRF) specifically designed for
 the study.

 Study Treatment:

 Biosimilar trastuzumab (Zedora) must be prescribed at the dosage described in the product
 label.

 Treatment duration will be 12 months for patients starting upfront with biosimilar
 trastuzumab (Zedora). Patients switching at any time to biosimilar trastuzumab (Zedora) after
 a period of adjuvant or neoadjuvant Herceptin® use will also be included in the overall
 analysis and subsequently assessed in a subgroup analysis.

 Sample Size:

 Number of patients = 170 Given the inexistence of a specific hypothesis to be tested, the
 statistical analysis will be basically descriptive.

 Sample size is based on the two-sided 95% confidence interval (95% CI) for the invasive
 disease relapse-free survival rate.

 The table below shows the 95% CIs for different rates in a sample of 170 patients, with an
 interval size ranging between 9% and 15%.

 Based on literature, a 3-year relapse-free survival between 88 and 96% is expected. According
 to the table above, a sample of 170 patients allows assessing this endpoint with +/- 6.0%
 accuracy.

 Study duration:

 The estimated time for patient enrollment in the study is one year and may be extended in
 case the sample size is not reached in this period. Biosimilar trastuzumab (Zedora) must be
 prescribed according to the product label and treatment duration will be up to one year. The
 patient will be maintained in the study for 5 years (from start of treatment), unless there
 is tumor recurrence (local or distant).
Inclusion Criteria:

 -  female patients aged 18 years and over

 -  diagnosis of early stage I to III breast cancer confirmed by histopathology test
 according to local guidelines.

 -  human epidermal growth factor receptor 2 (HER2)-positive tumor by immunohistochemistry
 or FISH (Fluorescence In Situ Hybridization), as per the 2018 ASCO assessment
 guideline [J Clin Oncol 36:2105, 2018].

 -  use of at least one dose of biosimilar trastuzumab (Zedora) as adjuvant therapy,
 regardless of previous neoadjuvant trastuzumab or Zedora use or the type of
 chemotherapy combined with the antibody.

 -  Signing of the informed consent form (ICF).

 Exclusion Criteria:

 -  use of biosimilar trastuzumab (Zedora) differently from the provisions in the label.

 -  patients enrolled in and followed up by Programa Vida Plena [Full Life Program].