Birth control
Women having periods (or whose periods stopped due to chemotherapy) may need to use barrier contraception (such as condoms) while taking trastuzumab, and for at least six months afterwards. This is because of the possibility of harming a developing fetus. Mechanism of action
The HER2 gene (also known as HER2/neu and ErbB2 gene) is amplified in 20–30% of early-stage breast cancers. Trastuzumab is a monoclonal antibody targeting HER2, inducing an immune-mediated response that causes internalization and recycling of HER2. It may also upregulate cell cycle inhibitors such as p21Waf1 and p27Kip1.The HER2 pathway promotes cell growth and division when it is functioning normally; however, when it is overexpressed, cell growth accelerates beyond its normal limits. In some types of cancer, the pathway is exploited to promote rapid cell growth and proliferation and hence tumor formation. The EGF pathway includes the receptors HER1 (EGFR), HER2, HER3, and HER4; the binding of ligands (e.g. EGF etc.) to HER receptors is required to activate the pathway. The pathway initiates the MAP kinase pathway as well as the PI3 kinase/AKT pathway, which in turn activates the NF-κB pathway. In cancer cells the HER2 protein can be expressed up to 100 times more than in normal cells (2 million versus 20,000 per cell). This overexpression leads to strong and constant proliferative signaling and hence tumor formation.
Iran also approved its own version of the monoclonal antibody in January 2016, as AryoTrust, and announced its readiness to export the drug to other countries in the Middle-East and Central Asia when trade sanctions were lifted.In 2016, the investigational biosimilar MYL-1401O has shown comparable efficacy and safety to the Herceptin branded trastuzumab.Trastuzumab-dkst (Ogivri, Mylan GmbH) was approved in the United States in December 2017, to "treat patients with breast cancer or gastric or gastroesophageal junction adenocarcinoma whose tumors overexpress the HER-2 gene." Ogivri was approved for medical use in the European Union in December 2018.In November 2017, the European Commission approved Ontruzant, a biosimilar-trastuzumab from Samsung Bioepis Co., Ltd, for the treatment of early breast cancer, metastatic breast cancer and metastatic gastric cancer. Ontruzant is the first trastuzumab biosimilar to receive regulatory approval in Europe.Herzuma was approved for medical use in the European Union in February 2018. Herzuma, a trastuzumab biosimilar, was approved in the United States in December 2018. The approval was based on comparisons of extensive structural and functional product characterization, animal data, human pharmacokinetic, clinical immunogenicity, and other clinical data demonstrating that Herzuma is biosimilar to US Herceptin.