Efficacy and safety of pyrotinib-based regimens in patients with HER2-positive stage III/IV breast cancer: a real-world retrospective study in China.

Background: Data from multiple clinical trials have shown that pyrotinib has demonstrated significant efficacy and acceptable tolerability in patients with HER2-positive advanced breast cancer (BC). However, the short time to market in China limits our comprehensive understanding of the drug's long-term efficacy and potential adverse events (AEs) from the drug. Therefore, this study analyzed the clinical efficacy and safety of pyrotinib-based regimens in a real-world database. Materials and Methods: This study retrospectively analyzed patients with HER2-positive stage III/IV BC who were treated with pyrotinib-based regimens from October 2018 to October 2022 at the Affiliated Tumor Hospital of Guangxi Medical University. Tumor assessments were based on RECIST 1.1, and AEs were assessed and graded according to NCI-CTCAE 5.0. Long-term efficacy was evaluated by calculating median progression-free survival (mPFS, defined as the time from treatment initiation until disease progression or death). Results: Of the 37 included patients, the objective response rate (ORR) was 62.2%, the disease control rate (DCR) was 94.6%, and the median progression-free survival length was 12.0 months (95% CI [5.8 ∼18.2] months). A subgroups comparison found that significant differences were observed in patients who had not used lapatinib ( Conclusion: Pyrotinib-based regimens have shown satisfactory clinical efficacy in HER2-positive stage III/IV BC patients, and pyrotinib is well tolerated with manageable adverse events.