Efficacy and safety of pyrotinib for patients with HER2-positive advanced breast cancer : a retrospective multicenter real-world study

Purpose: The incidence of breast cancer ranks first among female malignancies that affect women's health. Human epidermal growth factor 2 (HER2) positive breast cancer accounts for 20% − 30% of the invasive breast cancer, which is related to the poor prognosis of the tumor. This study aimed to observe the efficacy and safety of pyrotinib in HER2-positive advanced breast cancer in the real world. Methods This multicenter retrospective study was performed on the clinical data of HER2-positive advanced breast cancer patients treated with pyrotinib from March 2019 to April 2022. Progression-free survival (PFS), overall survival (OS), objective response rate (ORR), disease control rate (DCR), clinical benefit rate (CBR) and occurrence of adverse events were observed after treatment, and possible predictors of efficacy were explored. Results A total of 91 female patients enrolled, with a median age of 51 years (range, 30–76), a median PFS of 14.3 months (95%CI: 8.8–19.8), and a median OS of 30.0 months (95%CI: 23.8–36.2). Short-term efficacy showed that 4 cases of complete remission (CR), 61 cases of partial remission (PR), 23 cases of stable disease (SD) and 3 cases of progression disease (PD) were identified, and the ORR, DCR and CBR were 71.4%, 96.7% and 74.7%, respectively. The main treatment-related adverse event was diarrhea. Log-rank analysis showed a significant difference in OS between patients with liver metastases and patients with non-liver metastases (15.8 months vs 31.4 months, HR = 2.30, P  < 0.05). The results of the Cox regression model indicated that the number of pyrotinib treatment lines was an independent risk factor affecting PFS and OS of patients (HR PFS =1.81, HR OS =1.91, P  < 0.05). Conclusions Pyrotinib-based regimens were safe and effective in the treatment of HER2-positive advanced breast cancer, and the earlier use was better. Pyrotinib-based therapy might have some advantages in patients without liver metastases. This study set the stage for further exploration of the treatment paradigm of pyrotinib.