Biosimilar trastuzumab active post marketing surveillance real world 2020 data update: Results from a patient support program for patients under treatment with the first biosimilar trastuzumab approved in Brazil.

Abstract

e14504 Background: In 2017, biosimilar trastuzumab (Zedora) became the first biosimilar trastuzumab approved in Brazil. In May 2018 an active postmarketing surveillance program was instituted. Data from this program was presented in ASCO in 2019 and 2020. Now, with an extended follow up (May 2018 to December 2020) and more patients included, we present updated data from the surveillance program. Methods: This is a prospective observational study to evaluate data from the patient support program. Patients who received prescription for biosimilar trastuzumab were invited to participate. After agreement of informed consent, they were followed by periodical phone calls after each infusion and up to 3 months after the end of treatment. Treatment related data and adverse events (AEs) were collected. Results: A total of 74 reports containing 656 adverse events (AEs) were received from the active postmarketing surveillance program between May 2018 and December 2020. Of the 74 reports, 73 are female patients with HER2+ breast cancer (BC) and 1 is a male patient with gastric adenocarcinoma. The patients mean age was 52 years (31 to 79 years). Regarding to AEs severity and expectedness, 588 (89.63%) were non-serious AE (413 expected / 175 unexpected) and 68 (10.37%) were serious AE (51 expected / 17 unexpected). Considering all serious unexpected AEs (17), 13 were assessed as not related to trastuzumab therapy and 4 were assessed as related to therapy. For the 175 non-serious unexpected AEs, 56 were assessed as not related to therapy and 119 were assessed as related to therapy. The three most frequently reported AEs according to SOC (System Organ Classification) were general disorders and administration site conditions 111 (16.92%), gastrointestinal disorders 98 (14.93%) and nervous system disorders 88 (13.41%). The five most commonly reported adverse events (MedDRA PT - Preferred term) were diarrhea 27 (4.11%), fatigue 24 (3.66%), nausea 22 (3.35%), weight decreased 18 (2.74%) and infusion related reaction 17 (2.59%). Further monitoring is continued. Conclusions: Nature of AEs noted in patients with breast cancer and gastric cancer treated with biosimilar trastuzumab (Zedora) were consistent with the known safety profile of Trastuzumab. The risk benefit remains consistent with the reference safety information and no new safety signals were detected.[Table: see text]