Abstract 285P
Background
Pyrotinib, a novel irreversible pan-ErbB receptor tyrosine kinase inhibitor, has shown promising antitumor activity and manageable toxicity in HER2-positive metastatic breast cancer. However, the efficacy and safety of pyrotinib-based treatment in the real-world setting in China is limited. The aim of this study was to evaluate actual clinical outcomes in HER2-positive metastatic breast cancer treated with pyrotinib.
Methods
In this retrospective study, 275 patients who received pyrotinib-based therapy for HER2-positive metastatic breast cancer from 12 institutions between March 2019 to August 2020 were initially included. Progression-free survival (PFS), objective response rate (ORR), and treatment-related adverse events (TRAEs) were analyzed.
Results
Eight out of 275 patients were lost to follow up and the clinical outcomes of 267 patients were reported in this study. Of them, 213 (79.8%) patients had visceral metastatic lesions, 141 (52.9%) had more than 3 metastatic sites, 240 (89.9%) had received trastuzumab-based therapy, 54 (20.2%) had received lapatinib-based therapy, and 226 (84.7%) received pyrotinib-based therapy as a second or further line of treatment. The treatment regimens of 267 patients included pyrotinib alone (11.2%), pyrotinib in combination with capecitabine (58.4%), vinorelbine (6.0%), or nab-paclitaxel (5.2%). The median age and follow-up time were 51 years and 8.0 months, respectively. The median PFS of 267 patients was 11.0 months. Lapatinib-naïve patients had significantly longer PFS than lapatinib-treated patients (12.0 months vs. 5.0 months, P<0.0001). Of 254 patients who were available for ORR evaluation, 5 (2.0%) achieved complete response, and 84 (33.1%) had partial response. ORR for lapatinib-naive and lapatinib-treated patients was 38.0% and 24.5%, respectively. The most common grade 3 or 4 adverse events were diarrhea (18.0%), hand-foot syndrome (6.7%) and mucositis (2.6%).
Conclusions
Among patients with HER2-positive metastatic breast cancer, pyrotinib-based therapy demonstrated encouraging effects and acceptable tolerability in the real-world setting. More data would be further analyzed and reported.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.