Abstract 290P
Background
Trastuzumab emtansine (T-DM1) has shown great effectiveness in treating HER2-positive metastatic breast cancer, but therapies after T-DM1 progression are still controversial. Here, we report the real-world data of tyrosine kinase inhibitors (TKIs) based therapy in T-DM1 resistant HER2-positive metastatic breast cancer.
Methods
From August 2019 to April 2021, 48 HER2-positive metastatic breast cancer patients received TKIs-based therapy after T-DM1 progression in Jiangsu Province Hospital. We evaluated the efficacy and safety of TKIs in treating T-DM1 resistant HER2-positive metastatic breast cancer.
Results
48 patients received TKIs-based therapies as a second or later line therapy. 46 (95.8%) patients received a combined therapy, including TKIs plus capecitabine, vinorelbine or trastuzumab. 2 (4.2%) patients received TKIs alone. The median progression-free survival (PFS) was 10.5 months (95%CI 5.432-15.568). Objective response rate (ORR) was 17.4%, and clinical benefit rate (CBR) was 73.9%. For patients who had brain metastasis (n=11), the median PFS was 10.5 months (95%CI 7.406-13.594) and intracranial ORR was 27.3%. No difference was observed between lapatinib (n=32) and pyrotinib (n=16) groups (8.0 months vs. 13.3 months, P=0.243). The most common adverse events were hand-foot syndrome (11, 22.9%) and thrombocytopenia (10, 20.8%).
Conclusions
TKIs-based therapy could improve the survival of T-DM1 resistant HER2-positive metastatic breast cancer patients, including those with brain metastasis. This provides a new therapeutic option for HER2-positive breast cancer treatments.
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.