Trastuzumab biosimilars vs trastuzumab originator in the treatment of HER2-positive breast cancer: a systematic review and network meta-analysis

Breast cancer is the most frequently diagnosed cancer in women and ranks second among causes for cancer related death in women. Trastuzumab originator (Herceptin) is a monoclonal antibody used as a standard treatment for breast and metastatic gastric cancer when the cancer cells over-express human epidermal growth factor receptor type 2 (HER2). As the patent of Trastuzumab has now expired, biosimilars are moving into the market. It is still controversial to chose which trastuzumab biosimilar has the best treatment of HER2-positive breast cancer patients. We conducted this network meta-analysis to explore the best trastuzumab biosimilar in the treatment of HER2-positive breast cancer patients.PubMed, Cochrane library databases, China National Knowledge infrastructure (CNKI) and WanFang database up to November 2021 were systematically searched. The following search terms were used: 'trastuzumab originator', and 'trastuzumab biosimilar'. No language restriction was imposed. The reference lists of all retrieved articles were also reviewed to identify additional articles missed by using these search terms.We got 10 studies to conduct network meta-analysis to evaluate efficacy and serious adverse reactions among various trastuzumab biosimilars and trastuzumab originator. The overall response rate (ORR) and pathological complete response (pCR) of SB3 were worse than trastuzumab originator significantly, while the ORR and pCR of other trastuzumab biosimilars had not yet reached statistical differences compared with each other. The cumulative ranking curve (SUCRA) probability indicated that the ORR from best to worst was CT-P6, Herceptin, HLX02, PF-05280014, R-TPR-016, BCD-022, MYL-1401O, SB3, and the pCR from best to worst was PF-05280014, CT-P6, Herceptin, ABP-980, SB3. The serious adverse events (SAEs) of CT-P6 were more than Herceptin and MYL-1401O significantly, while the SAEs of other trastuzumab biosimilars had not statistical differences. The SUCRA probability indicated that the SAEs from best to worst was MYL-1401O, Herceptin, PF-05280014, SB3, HLX02, BCD-22, CT-P6.There was no statistical difference in both ORR and pCR of various trastuzumab biosimilars and Herceptin except SB3. The ORR and pCR of SB3 were worse than Herceptin. Both CT-P6 and PF-05280014 are better in the overall curative effect, but CT-P6 had the highest serious adverse reactions when compared with others. The PF-05280014 might be a better trastuzumab biosimilar in the treatment of HER2-positive breast cancer patients.