Journal Article

Activity and safety of SHR3680, a novel antiandrogen, in patients with metastatic castration-resistant prostate cancer: a phase I/II trial

Du, Chuanjun, Wan, Ben, Sun, Zhongquan, Yang, Xinfeng, Bai, Aobing, Yao, Xin, Ji, Dongmei, Han, Weiqing, Ye, Dingwei, Zou, Qing, He, Chaohong, Chong, Tie, Luo, Hong, Jin, Chunlei, Qin, Xiaojian, Zou, Jianjun, Zhu, Shaoxing, Gu, Weijie

2022

Overview

Background Antagonizing the androgen-receptor (AR) pathway is an effective treatment strategy for patients with metastatic castration-resistant prostate cancer (CRPC). Here, we report the results of a first-in-human phase 1/2 study which assessed the safety, pharmacokinetics, and activity of SHR3680 (a novel AR antagonist) in patients with metastatic CRPC. Methods This phase 1/2 study enrolled patients with progressive metastatic CRPC who had not been previously treated with novel AR-targeted agents. In the phase 1 dose-escalation portion, patients received oral SHR3680 at a starting daily dose of 40 mg, which was subsequently escalated to 80 mg, 160 mg, 240 mg, 360 mg, and 480 mg per day. In phase 2 dose-expansion portion, patients were randomized to receive daily dose of 80 mg, 160 mg, or 240 mg of SHR3680. The primary endpoint in phase 1 was safety and tolerability and in phase 2 was the proportion of patients with a prostate-specific antigen (PSA) response (≥ 50% decrease of PSA level) at week 12. Results A total of 197 eligible patients were enrolled and received SHR3680 treatment, including 18 patients in phase 1 and 179 patients in phase 2. No dose-limiting toxicities were reported and the maximum tolerated dose was not reached. Treatment-related adverse events (TRAEs) occurred in 116 (58.9%) patients, with the most common one being proteinuria (13.7%). TRAEs of grade ≥ 3 occurred in only 23 (11.7%) patients, and no treatment-related deaths occurred. Antitumor activities were evident at all doses, including PSA response at week 12 in 134 (68.0%; 95% CI, 61.0–74.5) patients, stabilized bone disease at week 12 in 174 (88.3%; 95% CI, 87.2–95.5) patients, and responses in soft tissue lesions in 21 (34.4%, 95% CI, 22.7–47.7) of 61 patients. Conclusion SHR3680 was well tolerated and safe, with promising anti-tumor activity across all doses tested in patients with metastatic CRPC. The dose of 240 mg daily was recommended for further phase 3 study. Trial registration Clinical trials.gov NCT02691975; registered February 25, 2016.

• Publisher: BioMed Central,BioMed Central Ltd,BMC
• Subject: Androgen Antagonists - pharmacokinetics / Androgen Antagonists - therapeutic use / Androgen Receptor Antagonists - therapeutic use / Androgen-receptor antagonist / Antiandrogens / Biomedicine / Castration-resistant prostate cancer / Dosage and administration / Drug therapy / Health aspects / Humans / Male / Maximum Tolerated Dose / Medicine / Medicine & Public Health / Metastasis / Patient outcomes / Phase 1/2 study / Prostate cancer / Prostate-Specific Antigen / Prostate-specific antigen response / Prostatic Neoplasms, Castration-Resistant - drug therapy / Prostatic Neoplasms, Castration-Resistant - pathology / Research Article / SHR3680 / Targeted Therapies