Abstract P3-02-07: Combined Chemo-endocrine Therapy Maybe a New Option for HR+/HER2− Advanced Breast Cancer: A Prospective, Single-center Clinical Study of Fulvestrant plus Oral Vinorelbine
Authors: Wang Xue , Yue Jian , Wang Jiayu , Zhang Pin , Ma Fei , Xu Binghe , Yuan Peng 
Published: March 2023

Background Fulvestrant have demonstrated synergistic antitumor effect with chemotherapy regimen. This study evaluates the efficacy and safety of Fulvestrant with Vinorelbine in patients with hormone receptor positive (HR+)/human epidermal growth factor receptor-2-negative (HER2−) recurrent or metastatic breast cancer. Methods In this prospective, single-arm and investigator-initiated clinical study, patients with recurrent or metastatic HR+/HER2− breast cancer after the first line adjuvant endocrine therapy for &gt; 1 year were eligible, in which the subjects of the first line was defined as the patients with recurrence and metastasis after adjuvant endocrine therapy for over 1 year and did not receive treatment for the recurrence and metastasis and the second-line defined as the patients who had disease progression after receiving first-line endocrine therapy or first-line chemotherapy). Patients were administered i.m. Fulvestrant 500mg (day 1 per cycle for 28 days) and oral Vinorelbine (60 mg/m2 on day 1, 8 and 15 of each cycle). The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate (ORR), disease control rate (DCR), duration of response (DoR), and safety. The Kaplan–Meier method and log-rank test were used to evaluate PFS and OS. Results Total 38 HR+/HER2- advanced breast cancer patients with median follow-up time (25.1 months) were enrolled in, and median PFS [9.86 months (95% CI: 7.2, 23.13)] were discovered. The median PFS of the first-line and the second-line treatment population were 20.73 months (95% CI: 9.82, NR) and 4.27 months (95% CI: 3.68, NR), respectively. The median OS of the intent-to-treat (ITT) and the first-line treatment population were not reached, and the OS of the second-line treatment was 28.2 months (95% CI: 11.5, NR). The ORR of the ITT population was 39.47% (95% CI: 23.93, 55.01). The ORR of the patients receiving first-line and second-line treatments were 44.44% (95% CI: 25.70, 63.19) and 27.27% (95% CI: 0.95, 53.59), respectively. The DCR of ITT population was 92.11% (95% CI: 83.54, 100.00)], and the median DoR was approximately 15.33 months (95% CI: 7.23, 22.54)]. In the safety analysis, most of the adverse events were grade of 1/2, and none of grade 4/5 adverse events were reported. Conclusion This is the first exploratory study of Fulvestrant with oral Vinorelbine regimen in the treatment of HR+/HER2− recurrent and metastatic breast cancer conducted worldwide. The combinative chemo-endocrine therapy was efficacious, safe and promising for patients with HR+/HER2− advanced breast cancer.

Citation Format: Xue Wang, Jian Yue, Jiayu Wang, Pin Zhang, Fei Ma, Binghe Xu, Peng Yuan. Combined Chemo-endocrine Therapy Maybe a New Option for HR+/HER2− Advanced Breast Cancer: A Prospective, Single-center Clinical Study of Fulvestrant plus Oral Vinorelbine [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-02-07.