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 (EBC) in China: Updated interim analysis from the NER-Tree study.

Abstract

e12507 Background: Neratinib, a pan-HER tyrosine kinase inhibitor, was approved in China in 2020 based on the results of the ExteNET trial. With the increasing use of neoadjuvant treatment and recent approval of additional adjuvant anti-HER2 therapies, the current treatment landscape for HER2+ EBC in China has recently evolved. A real-world study investigating neratinib use in a Chinese population will provide valuable insights into the evolving landscape of HER2+ EBC and offer a better understanding of neratinib's effectiveness and safety in patients who have received different prior treatments. Methods: This is a multi-center, prospective, non-interventional study enrolled 500 patients with HER2+ EBC scheduled to receive extended adjuvant neratinib treatment. (NCT05491057) The primary and secondary objectives are to describe real-world adjuvant treatment patterns and to observe the safety of neratinib, respectively. This interim analysis will report the patient characteristics and prior treatments before receiving extended adjuvant neratinib. Results: As of 28 October 2024, 500 patients were included in the analysis. The median age of patients was 50.5 years. A total of 328 patients (65.6%) were postmenopausal. At primary diagnosis, a total of 275 patients (55.0%) had HER2+/hormone receptor positive (HR+) tumors; 286 patients (57.2%) had stage I-II tumors, and 183 patients (36.6%) had stage III tumors. A total of 166 patients (33.2%) received neoadjuvant therapy. Ninety-six of them (57.8%) did not achieve pCR. Trastuzumab plus pertuzumab was the most used neoadjuvant (n=152, 91.6%) and adjuvant (451, 90.2%) treatment. The median time from completion of previous adjuvant therapy until the start of neratinib treatment was 1.14 months (interquartile range: 0.69 - 2.43). The initial dose of neratinib was <240 mg for 67% and 240 mg for 33% of the patients. Two hundred ninety-seven patients (59.4%) adopted anti-diarrheal strategies at least once, including drug prophylaxis (loperamide or other agents (90, 18%), dose escalation (140, 28%), or both (67, 13.4%). Conclusions: The profile of patients and pattern of anti-HER2 treatment prior to extended adjuvant neratinib reflected the current treatment landscape for HER2+ EBC in China. With increasing clinical experience, more than half of patients using neratinib in the real-world setting are now receiving diarrhea prophylaxis. Clinical trial information: NCT05491057 . Adjuvant regimen Total N=500 Patients with neoadjuvant treatment, n (33.2%) Patients without neoadjuvant treatment, n N=334 (66.8%) Totaln=166 pCRn=59 (35.5%) non-pCRn=96 (57.8%) Trastuzumab 38 (7.6) 3 (1.8) 0 3 (3.1) 35 (10.5) Trastuzumab+Pertuzumab 451 (90.2) 153 (92.2) 59 (100) 85 (88.5) 298 (89.2) T-DM1 9 (1.8) 9 (5.4) 0 8(8.3) 0 Other anti-HER2 therapy 2 (0.4) 1 (0.6) 0 0 1(0.3)