118P A multicenter, prospective, non-interventional study to investigate the treatment patterns of neratinib in human epidermal growth factor receptor 2-positive (HER2+) early breast cancer in China: NER-Tree study - An interim analysis on patient characteristics and pretreatment patterns

Neratinib, an oral irreversible pan-HER tyrosine kinase inhibitor, was approved in 2020 in China based on the ExteNET trial, which is no longer reflective of the current treatment landscape of HER2+ early breast cancer (EBC) in China, with increasing clinical uses of neoadjuvant treatment and recently approved adjuvant anti-HER2 therapies including pertuzumab and trastuzumab emtansine. Thus, there is a need to understand the real-world extended adjuvant neratinib use in China. This is a multi-center, prospective, non-interventional study planning to enroll 500 HER2+ EBC patients who scheduled 1 year neratinib treatment after anti-HER2 adjuvant therapy. Pre-specified interim analyses are planned after recruitment of 250 and 500 patients. The primary and secondary objectives are to describe the real-world adjuvant treatment patterns and to observe the safety of patients treated with neratinib respectively. The exploratory objectives are to observe invasive disease recurrence patterns and patient-reported quality of life. As of 21 September 2023, 250 patients are included in the analysis. The median age of patients was 50.0 years. A total of 161 patients (64.4%) were postmenopausal. At primary diagnosis, 57.2% of the patients had HER2+/hormone receptor positive (HR+) tumors; 24.4% of the patients had cT1 and 57.2% had cT2; 73.6% of patients were N+ and 88.4% had Stage II+ III tumors. A total of 84 patients (33.6%) received neoadjuvant therapy. Fourt-five (53.6%) patients did not achieve a pCR. Trastuzumab plus pertuzumab was the most commonly used neoadjuvant therapy whether the patient achieved pCR or not (97.6% for pCR, 92.3% for non-pCR). A total of 250 patients (100%) received adjuvant treatment, of whom 88% received trastuzumab plus pertuzumab and 10.4% received trastuzumab only. The results from the NER-Tree study describe the use of the extended adjuvant neratinib in patients with HER2+ EBC that received more recent anti-HER2 therapies including pertuzumab in combination with trastuzumab in China.