Long-term Outcome Analysis of Pyrotinib in Patients With HER2-Positive Metastatic Breast Cancer and Brain Metastasis: A Real-World Study

Pyrotinib is approved for the treatment of HER2-positive advanced breast cancer in China; however, data on overall survival and efficacy in patients with brain metastasis are scarce. This study evaluated the effectiveness of pyrotinib in a real-world setting, especially in patients with brain metastasis. Background Pyrotinib is currently approved for the treatment of HER2-positive advanced breast cancer in China. Data on the overall survival (OS) and efficacy in patients with brain metastasis (BM) remain scarce. This study evaluated the effectiveness of pyrotinib in a real-world setting, especially in patients with BM. Methods We reviewed patients with metastatic breast cancer treated with pyrotinib-based therapy between June 2018 and June 2022. Progression-free survival (PFS), OS, objective response rate, and safety were analyzed following the administration of pyrotinib. Results A total of 239 patients were included. The median PFS in patients who received pyrotinib-based therapy as first-line (15/239), second-line (115/239), or third-or-higher-line (109/239) treatment was 14.00, 9.33, and 8.20 months, respectively, and the median OS was not reached, 29.07 and 22.23 months, respectively. The median PFS in patients who pretreated with trastuzumab (214/239), trastuzumab plus pertuzumab (22/239), lapatinib (68/239), or trastuzumab emtansine (14/239) was 9.33, 6.87, 7.20, and 7.20 months, respectively. In 61 patients with BM, the median PFS was 7.50 months, the median central nervous system (CNS)-PFS was 11.17 months, and the median OS was 21.27 months. Furthermore, 19 patients with concomitant brain radiotherapy tended to achieve a longer OS than 42 patients without radiation (34.17 vs. 20.70 months, P = .112). Conclusions Long-term outcomes of pyrotinib-based therapy are promising for patients with HER2-positive metastatic breast cancer in real world and in patients with BM, regardless of the treatment lines and prior anti-HER2 therapies.