The efficacy and safety of pyrotinib in treating HER2-positive breast cancer patients with brain metastasis: A multicenter study

Purpose To investigate the efficacy and safety of pyrotinib in treating patients with human epidermal growth factor receptor type 2 (HER2)‐positive breast cancers with brain metastasis. Patients and Methods This is a multicenter retrospective study, and the HER2‐positive breast cancer patients with brain metastasis were studied. The enrolled patients were given pyrotinib 400 mg orally once per day for 21 days as one cycle, and evaluated every two cycles. All relevant data were detected for final assessments including medical history, clinical examination, histopathology, immunohistochemistry, radiographic imaging, treatment outcome, and adverse events. Results Forty‐two female patients in total were enrolled in this study. The objective response rate (ORR) and disease control rate (DCR) of central nervous system (CNS), were found in 20 of 42 (47.6%) and in 39 of 42 (92.8%), respectively, while for extra‐CNS, the respective ORR and DCR were in 9 of 38 (23.6%) and in 36 of 38 (94.7%), respectively. The compounded ORR and DCR were seen in 17 of 42 (40.4%) and in 39 of 42 (92.8%), respectively. The improvement rate of craniocerebral symptoms after treatment was (19/19) 100% and the median duration was 15 months. The median effective time of brain metastases and other metastases was 43 and 50 days. The median follow‐up time was 22 months (interquartile range, 16.0–24.3 months). The median time for progression in brain metastasis was 16.6 months. The median time to progress for our group patients was 11.1 months. Sixteen patients (36%) with adverse reactions were recorded in the study. Conclusion Pyrotinib combined with chemotherapy/radiotherapy or alone showed significantly greater local control rates and progression free survival (PFS), with manageable toxicity for patients with HER2‐positive breast cancer with brain metastases, and further follow‐up will provide an overall survival (OS) data.