Pyrotinib for HER2-positive metastatic breast cancer: a systematic review and meta-analysis

BACKGROUND: Human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer patients continue to progress despite multiple anti-HER2-targeted treatments. A number of studies have found that Pyrotinib, a small-molecule pan-ErbB receptor tyrosine kinase inhibitor (TKI), is effective in treating patients with HER2-positive metastatic breast cancer. This systematic review and meta-analysis aimed to evaluate the efficacy and safety of Pyrotinib in the treatment of HER2-positive metastatic breast cancer. METHODS: PubMed, Embase, Web of Science, and Cochrane Library databases were searched until February 2022. Research on HER2-positive metastatic breast cancer being treated with Pyrotinib in any line of therapy was included, both prospective and retrospective. Statistical pooling and meta-analysis of data from the included studies were performed to explore the efficacy and safety of Pyrotinib in HER2-positive metastatic breast cancer. RESULTS: In this meta-analysis, 23 studies were included. The overall objective response rate was 0.49 (95% CI: 0.40, 0.58) for Pyrotinib in HER2-positive metastatic breast cancer and 0.52 (95% CI: 0.32, 0.71) in those with brain metastases. The objective response rate of Pyrotinib was superior to that of other second-line therapeutics in comparison (RR =1.38, 95% CI: 1.25, 1.52), but was relatively inferior to trastuzumab emtansine (T-DM1) (RR =0.82, 95% CI: 0.36, 1.85). The combined median progression-free survivals (PFSs) for Pyrotinib in metastatic breast cancer and those with brain metastases were 8.2 (95% CI: 6.8, 9.5) months and 8.9 (95% CI: 6.2, 11.7) months, respectively. The most common adverse reaction was diarrhea with an all-grade incidence of 0.84 (95% CI: 0.74, 0.92), followed by nausea and vomiting of 0.52 (95% CI: 0.36, 0.68). CONCLUSIONS: In any line of treatment for HER2-positive metastatic breast cancer, the Pyrotinib-containing regimens demonstrated considerable tumor response, disease control, and survival with manageable adverse effects.