Dose tapering to withdrawal stage and long-term efficacy and safety of hetrombopag for the treatment of immune thrombocytopenia: Results from an open-label extension study

Heng Mei, Xiaofan Liu, Yan Li, Hu Zhou, Ying Feng, Guangxun Gao, Peng Cheng, Ruibin Huang, Linhua Yang, Jianda Hu, Ming Hou, Yazhou Yao, Li Liu, Yi Wang, Depei Wu, Liansheng Zhang, Changcheng Zheng, Xuliang Shen, Qi Hu, Jing Liu, Jie Jin, Jianmin Luo, Yun Zeng, Sujun Gao, Xiaohui Zhang, Xin Zhou, Qingzhi Shi, Ruixiang Xia, Xiaobao Xie, Zhongxing Jiang, Li Gao, Yuansong Bai, Yan Li, Junye Xiong, Runzi Li, Jianjun Zou, Ting Niu, Renchi Yang, Yu Hu, Heng Mei, Xiaofan Liu, Yan Li, Hu Zhou, Ying Feng, Guangxun Gao, Peng Cheng, Ruibin Huang, Linhua Yang, Jianda Hu, Ming Hou, Yazhou Yao, Li Liu, Yi Wang, Depei Wu, Liansheng Zhang, Changcheng Zheng, Xuliang Shen, Qi Hu, Jing Liu, Jie Jin, Jianmin Luo, Yun Zeng, Sujun Gao, Xiaohui Zhang, Xin Zhou, Qingzhi Shi, Ruixiang Xia, Xiaobao Xie, Zhongxing Jiang, Li Gao, Yuansong Bai, Yan Li, Junye Xiong, Runzi Li, Jianjun Zou, Ting Niu, Renchi Yang, Yu Hu

Abstract

Background: The efficacy of hetrombopag in Chinese patients with immune thrombocytopenia (ITP) has been demonstrated in a randomized, double-blind, placebo-controlled, multicenter, phase III trial (NCT03222843).

Objective: This study aimed to report comprehensive data on a ≤6-week dose tapering to withdrawal (Stage 3) and an additional 24-week long-term extension period (Stage 4) in this phase III trial.

Patients/methods: Patients who fulfilled the screening criteria were eligible to enter Stage 3 or 4. During Stage 3, hetrombopag was gradually tapered to withdrawal. During Stage 4, hetrombopag treatment was initiated at 2.5, 3.75, 5, or 7.5 mg once daily. The efficacy endpoints during Stage 3 or 4 and the safety profile during the entire treatment period were reported.

Results: Among 194 patients who entered Stage 3, 171 (88.1%) relapsed. The median time to the first relapse since the start of Stage 3 was 15.0 days (95% CI, 14.0-16.0). In Stage 4, 144 (42.5%) patients responded at ≥75% of their assessments and 254 (74.9%) patients achieved platelet count ≥30 × 109 /L at least once, which was at least twice their baseline platelet count in the hetrombopag group (n = 339). The most common adverse events were upper respiratory tract infection (53.1%), thrombocytopenia (27.1%), and urinary tract infection (21.2%) in the hetrombopag group.

Conclusion: The majority of patients who experienced dose tapering to withdrawal experienced a relapse. Long-term treatment with hetrombopag was effective in increasing and maintaining platelet count within the desired range in Chinese adults with ITP. Hetrombopag was well tolerated.

Keywords: extension period; hetrombopag; immune thrombocytopenia; platelet response; thrombopoietin receptor agonist; withdrawal.

© 2021 International Society on Thrombosis and Haemostasis.

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Source: PubMed

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