Pyrotinib plus capecitabine for trastuzumab-resistant, HER2-positive advanced breast cancer (PICTURE): a single-arm, multicenter phase 2 trial
Jun Cao, Yuee Teng, Huiping Li, Lili Zhang, Quchang Ouyang, Weimin Xie, Yueyin Pan, Zhenchuan Song, Xiaoling Ling, Xiaohong Wu, Jingwei Xu, Li Li, Liping Ren, Hong Wang, Dongxian Zhou, Jing Luo, Xichun Hu
Abstract
BACKGROUND: Patients with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer and primary resistance to trastuzumab have a poor clinical outcome and lack good evidence to inform clinical decision. This study investigated the efficacy and safety of pyrotinib plus capecitabine in this population. METHODS: twice a day on days 1-14 of each 21-day cycle until disease progression or intolerable toxicity. The primary endpoint was investigator-assessed progression-free survival (PFS). RESULTS: Between June 2019 and September 2021, 100 patients were enrolled with a median age of 51 years (range, 24-69). All patients had been treated with trastuzumab and 21 (21.0%) patients had prior use of pertuzumab. As of August 31, 2022, the median follow-up duration was 20.1 months (range, 1.3-38.2). The median PFS was 11.8 months (95% confidence interval [CI], 8.4-15.1), which crossed the pre-specified efficacy boundary of 8.0 months. The objective response rate was 70.0% (70/100), with a median duration of response of 13.8 months (95% CI, 10.2-19.3). The disease control rate was 87.0% (87/100). The median overall survival was not reached. The most common grade ≥ 3 treatment-emergent adverse event was diarrhea (24 [24.0%]). No treatment-related deaths occurred. CONCLUSIONS: Pyrotinib plus capecitabine can be considered to be a treatment option in HER2-positive advanced breast cancer patients who have shown primary resistance to trastuzumab. Even in the era of modern anti-HER2 treatments, this clinical setting warrants more investigations to meet unmet needs. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04001621. Retrospectively registered on June 28, 2019.