Active postmarketing surveillance: Results from a manufacturer's patient support program for patients under treatment with the first biosimilar trastuzumab (MYL-1401O) approved in Brazil.

Abstract

e14000 Background: The development of biosimilars is increasing around the world, and facilitates patient’s access to these high-tech therapies. Active pharmacovigilance is considered one of the main tools for monitoring the safety of biologics and biosimilars, especially in post marketing. In 2017, trastuzumab (MYL-1401O) became the first trastuzumab biosimilar approved in Brazil. A program to support patients under trastuzumab (MYL-14010) treatment was sponsored by the manufacturer in order to closely monitor adverse events (AE). Methods: This is a prospective observational study based in data from a manufacturer’s patient support program. Patient diagnosed with initial or advanced HER2+ breast cancer (BC) and HER2+ gastric cancer (GC) who received prescription for trastuzumab (MYL-1401O) were invited to participate. They are followed by periodical phone calls after each infusion and up to 3 months after the last infusion of trastuzumab. Treatment related data and AEs were collected. Results: A total of 21 female patients with HER2+ BC receiving trastuzumab (MYL-14010) were enrolled in the program between May 2018 and January 2019. 16 (76,2%) out of these patients with median age 52 years (range 33 to 76) reported 101 AEs (all-causality): 94 (93,1%) non-serious (73 expected / 21 unexpected) and 7 (6,9%) serious (5 expected / 2 unexpected). Considering all unexpected AEs causality assessment was unlikely in 47,8% AEs. The most frequently reported AEs according SOC (system organ classification) were general disorders and administration site conditions (18,8%), nervous system disorders (14,9%) and gastrointestinal disorders (14,9%). The most reported symptoms were nausea, asthenia, infusion reactions, paresthesias and pain in the body. Conclusions: Safety data for biosimilar trastuzumab (MYL-1401O) is consistent with original trastuzumab in female patients with HER2+ BC. Most of the reported AEs were non-serious (93,1%) and expected (77,2%). No new safety signals were detected.