A phase II clinical trial of neoadjuvant chemotherapy combined with immunotherapy and different radiotherapy fractionation regimens in HR+/HER2- breast cancer.
The modest neoadjuvant response in early-stage HR+/HER2- breast cancer necessitates novel treatment intensification strategies. While radiotherapy can enhance systemic efficacy via immune modulation, the optimal fractionation for integration with immunochemotherapy remains unknown. This multicenter phase II study aims to evaluate the feasibility, safety, and preliminary efficacy of Toripalimab combined with chemotherapy and tumor-directed radiotherapy, specifically investigating three distinct fractionation schedules.
This prospective, multicenter, three-cohort exploratory study enrolls treatment-naïve patients with early-stage HR+/HER2- breast cancer. Participants receive neoadjuvant Toripalimab plus chemotherapy alongside image-guided radiotherapy restricted to the primary tumor. Cohorts are differentiated by fractionation regimen: Arm 1 (8 Gy × 3 fractions, total 24 Gy); Arm 2 (16 Gy single fraction); Arm 3 (0.5 Gy twice daily for 8 cycles, cumulative 8 Gy). A total of 45 patients (15 per cohort) will be enrolled. The primary endpoint is pathological complete response (pCR). Secondary endpoints include objective response rate, recurrence, survival outcomes (OS, EFS, DMFS, IDFS, IBTR), and safety.
This exploratory study will provide feasibility, tolerability, and preliminary efficacy data for a novel multimodal neoadjuvant strategy combining different radiotherapy fractionation patterns with immunotherapy and chemotherapy. Given the descriptive analytical framework, findings are expected to be hypothesis generating and will inform the selection of radiotherapy schedules for future larger-scale randomized trials aimed at improving outcomes in HR+/HER2- breast cancer.
http://www.chictr.org.cn, identifier NCT06639672.
This prospective, multicenter, three-cohort exploratory study enrolls treatment-naïve patients with early-stage HR+/HER2- breast cancer. Participants receive neoadjuvant Toripalimab plus chemotherapy alongside image-guided radiotherapy restricted to the primary tumor. Cohorts are differentiated by fractionation regimen: Arm 1 (8 Gy × 3 fractions, total 24 Gy); Arm 2 (16 Gy single fraction); Arm 3 (0.5 Gy twice daily for 8 cycles, cumulative 8 Gy). A total of 45 patients (15 per cohort) will be enrolled. The primary endpoint is pathological complete response (pCR). Secondary endpoints include objective response rate, recurrence, survival outcomes (OS, EFS, DMFS, IDFS, IBTR), and safety.
This exploratory study will provide feasibility, tolerability, and preliminary efficacy data for a novel multimodal neoadjuvant strategy combining different radiotherapy fractionation patterns with immunotherapy and chemotherapy. Given the descriptive analytical framework, findings are expected to be hypothesis generating and will inform the selection of radiotherapy schedules for future larger-scale randomized trials aimed at improving outcomes in HR+/HER2- breast cancer.
http://www.chictr.org.cn, identifier NCT06639672.
Authors
Lan Lan, Sun Sun, Huang Huang, Zhao Zhao, Bi Bi, Huang Huang, Luo Luo, Jing Jing, Wu Wu, Liu Liu
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