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Jiang H, Ouyang Q, Yin Y, Tong Z, Shen K, Yuan Z, Geng C, Liu Y, Song G, Ran R, Li W, Qu Q, Wang M, Meng L, Tong Y, Li H. Proxalutamide in patients with AR-positive metastatic breast cancer: Results from an open-label multicentre phase Ib study and biomarker analysis. Eur J Cancer 2022; 176:1-12. [PMID: 36182805 DOI: 10.1016/j.ejca.2022.08.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/20/2022] [Accepted: 08/24/2022] [Indexed: 12/15/2022]
Abstract
AIM Proxalutamide is a novel second-generation non-steroidal androgen receptor (AR) antagonist. This study aimed to evaluate the preliminary efficacy and safety of proxalutamide in patients with AR-positive metastatic breast cancer (AR+ mBC). METHODS In this open-label, dose-expansion, multicentre phase Ib trial, patients with AR+ mBC (immunohistochemistry [IHC] ≥1%) received proxalutamide orally once daily. Two proxalutamide dose cohorts (cohort A: 200 mg; cohort B: 300 mg) were sequentially investigated. Primary endpoints were disease control rate (DCR) at 8 and 16 weeks and recommended phase II dose (RP2D). RESULTS Forty-five patients with three median lines (range, 1-13) prior systemic therapy were enrolled (cohort A, n = 30; cohort B, n = 15). Among 39 evaluable patients, DCR at 8 and 16 weeks was 25.6% (95% confidence interval [CI], 11.9-39.4%), with 26.9% in cohort A and 23.1% in cohort B. No patient achieved partial response or complete response. Proxalutamide 200 mg/day was determined as RP2D. The 6-month progression-free survival (PFS) rate was 19.6% (95% CI, 10.2-37.5%). In the triple-negative subgroup, DCR at 8 weeks was 38.5%, with median PFS of 9.1 months (95% CI, 7.8-NA) in those who achieved response at 8 weeks (n = 5). Most common grade 3/4 adverse events were aspartate aminotransferase increase (8.9%) and γ-glutamyltransferase increase (8.9%). By biomarker analysis, patients with moderate AR expression of IHC (26%-75%), PIK3CA pathogenic mutations, or <60 ng/ml cell-free DNA yield showed longer PFS. CONCLUSION Proxalutamide showed promising anti-tumour activity with good tolerability in patients with heavily pretreated AR+ mBC, supporting further investigation. TRIAL REGISTRATION This clinical study was prospectively registered at chinadrugtrials.org.cn (Identifier: CTR20170757) and clinical trials.gov (Identifier: NCT04103853).
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Affiliation(s)
- Hanfang Jiang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Breast Oncology, Peking University Cancer Hospital & Institute, Beijing, China
| | - Quchang Ouyang
- Department of Breast Oncology, Hunan Cancer Hospital, Changsha, Hunan, China
| | - Yongmei Yin
- Department of Breast Oncology, Jiangsu Province Hospital, Nanjing, Jiangsu, China
| | - Zhongshen Tong
- Department of Breast Oncology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Kunwei Shen
- Department of Breast Oncology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Zhongyu Yuan
- Department of Breast Oncology, Sun-Yat-sen University Cancer Center, Guangzhou, Guangdong, China
| | - Cuizhi Geng
- Department of Breast Centre, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Yaxin Liu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Breast Oncology, Peking University Cancer Hospital & Institute, Beijing, China
| | - Guohong Song
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Breast Oncology, Peking University Cancer Hospital & Institute, Beijing, China
| | - Ran Ran
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Breast Oncology, Peking University Cancer Hospital & Institute, Beijing, China
| | - Wei Li
- Department of Breast Oncology, Jiangsu Province Hospital, Nanjing, Jiangsu, China
| | - Qing Qu
- Department of Breast Oncology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Meiyu Wang
- Suzhou Kintor Pharmaceuticals, Inc., Suzhou, Jiangsu, China
| | - Luping Meng
- Suzhou Kintor Pharmaceuticals, Inc., Suzhou, Jiangsu, China
| | - Youzhi Tong
- Suzhou Kintor Pharmaceuticals, Inc., Suzhou, Jiangsu, China.
| | - Huiping Li
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Breast Oncology, Peking University Cancer Hospital & Institute, Beijing, China.
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