JSKN003 Versus Treatment Of Physician'S Choice For HER2-low, Unresectable and/or Metastatic Breast Cancer Subjects

September 8, 2025 updated by: Jiangsu Alphamab Biopharmaceuticals Co., Ltd

A Phase 3, Multicenter, Randomized, Open-Label, Active-Controlled Trial Of JSKN003 Versus Treatment Of Physician'S Choice For HER2-low, Unresectable and/or Metastatic Breast Cancer Subjects

This study is a randomized controlled, open-label, multicenter phase III clinical study evaluating the efficacy and safety of chemotherapy selected by investigator JSKN003 s in subjects with recurrent or metastatic breast cancer who have previously failed first- or second-line chemotherapy in subjects with recurrent or metastatic breast cancer who have failed prior first- or second-line chemotherapy.

The study planned to enroll 408 subjects in a 1:1 ratio and stratified block randomization method assigned to:

  • Experimental group: JSKN003 monotherapy
  • Control group: investigator's chosen chemotherapy drug (capecitabine, gemcitabine, vinorelbine, docetaxel, albumin-bound paclitaxel, or eribulin) monotherapy

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This study is a randomized controlled, open-label, multicenter phase III clinical study evaluating the efficacy and safety of chemotherapy selected by investigator JSKN003 s in subjects with recurrent or metastatic breast cancer who have previously failed first- or second-line chemotherapy in subjects with recurrent or metastatic breast cancer who have failed prior first- or second-line chemotherapy.

The study planned to enroll 408 subjects in a 1:1 ratio and stratified block randomization method assigned to:

  • Experimental group: JSKN003 monotherapy
  • Control group: investigator's chosen chemotherapy drug (capecitabine, gemcitabine, vinorelbine, docetaxel, albumin-bound paclitaxel, or eribulin) monotherapy.

Study Type

Interventional

Enrollment (Estimated)

400

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • China
      • Anyang, China
        • Not yet recruiting
        • Anyang Cancer Hospital
        • Contact:
          • Jing Sun
      • Baoding, China
        • Not yet recruiting
        • Affiliated Hospital of Hebei University
        • Contact:
          • Hua Yang
      • Beijing, China
        • Recruiting
        • Peking University Cancer Hospital
        • Contact:
          • Huiping Li
      • Beijing, China
        • Recruiting
        • Cancer hospital, Chinese Academy of Medical Sciences
        • Contact:
          • Peng Yuan
      • Beijing, China
        • Not yet recruiting
        • Beijing Luhe hospital
        • Contact:
          • Dong Yan
      • Beijing, China
        • Recruiting
        • The First Affiliated Hospital of China Medical University
        • Contact:
          • Yuee Teng
      • Beijing, China
        • Not yet recruiting
        • The First Medical Center of the General Hospital of the People's Liberation Army Chinese People's Liberation Army
        • Contact:
          • Weihong Zhao
      • Changchun, China
        • Not yet recruiting
        • Bethune First Hospital Of Jilin University
        • Contact:
          • Jiuwei Cui
      • Changchun, China
        • Not yet recruiting
        • Jilin Provincial Cancer Hospital
        • Contact:
          • Ying Liu
      • Changde, China
        • Recruiting
        • The First People's Hospital of Changde
        • Contact:
          • Tao Wu
      • Changsha, China
        • Recruiting
        • Hunan Cancer Hospital
        • Contact:
          • Quchang Ouyang
      • Changsha, China
        • Not yet recruiting
        • Central South University Xiangya Hospital
        • Contact:
          • Juan Huang
      • Chengde, China
        • Recruiting
        • Affiliated Hospital of Chengde Medical University
        • Contact:
          • Qingshan Li
      • Chengdu, China
        • Recruiting
        • Sichuan Provincial People's Hospital
        • Contact:
          • Jing Luo
      • Chengdu, China
        • Not yet recruiting
        • West China Hospital, Sichuan University
        • Contact:
          • Ting Luo
      • Chengdu, China
        • Recruiting
        • Sichuan Cancer Hospital
        • Contact:
          • Hao Wang
      • Chongqing, China
        • Not yet recruiting
        • The First Affiliated Hospital of Chongqing Medical University
        • Contact:
          • Lu Gan
      • Chongqing, China
        • Not yet recruiting
        • Cancer Hospital of Chongqing University
        • Contact:
          • Xianjun Tang
      • Dalian, China
        • Not yet recruiting
        • The Second Affiliated Hospital of Dalian Medical University
        • Contact:
          • man Li
      • Fuzhou, China
        • Not yet recruiting
        • Fujian Cancer Hospital
        • Contact:
          • Fan Wu
      • Fuzhou, China
        • Recruiting
        • Fujian Provincial Hospital
        • Contact:
          • Zhenhua Liu
      • Fuzhou, China
        • Recruiting
        • Union Hospital Affiliated to Fujian Medical University
        • Contact:
          • Fangmeng Fu
      • Ganzhou, China
        • Recruiting
        • The First Affiliated Hospital of Gannan Medical University
        • Contact:
          • Ruilian Xie
      • Guangzhou, China
        • Not yet recruiting
        • Sun Yat-sen Memorial Hospital, Sun Yat-sen University
        • Contact:
          • Jieqiong Liu
      • Guangzhou, China
        • Not yet recruiting
        • Guangdong Provincial People's Hospital
        • Contact:
          • Ning Liao
      • Guangzhou, China
        • Recruiting
        • The Affiliated Hospital of Guangdong Medical University
        • Contact:
          • Lixia Li
      • Guanzhou, China
        • Not yet recruiting
        • Sun yat-sen University Cancer Center
        • Contact:
          • Shusen Wang
      • Guiyang, China
        • Recruiting
        • Guizhou Provincial People's Hospital
        • Contact:
          • Yong Li
      • Guiyang, China
        • Recruiting
        • The Affiliated Hospital of Guizhou Medical University
        • Contact:
          • Yong Li
      • Hangzhou, China
        • Not yet recruiting
        • Run Run Shaw Hospital Affiliated to Zhejiang University School of Medicine
        • Contact:
          • Xian Wang
      • Hanzhou, China
        • Not yet recruiting
        • The First Affiliated Hospital of Zhejiang University School of Medicine
        • Contact:
          • Peifen Fu
      • Hanzhou, China
        • Not yet recruiting
        • The Second Affiliated Hospital of Zhejiang University School of Medicine
        • Contact:
          • Jian Huang
      • Hanzhou, China
        • Not yet recruiting
        • Zhejiang Cancer Hospital
        • Contact:
          • Hai Hu
      • Ha’erbin, China
        • Not yet recruiting
        • Harbin Medical University Cancer Hospital
        • Contact:
          • Qingyuan Zhang
      • Hefei, China
        • Not yet recruiting
        • The First Affiliated Hospital of Anhui Medical University
        • Contact:
          • Jiqing Hao
      • Hefei, China
        • Not yet recruiting
        • Anhui Provincial Hospital
        • Contact:
          • Yueyin Pan
      • Hefei, China
        • Not yet recruiting
        • The Second Affiliated Hospital of Anhui Medical University
        • Contact:
          • Fufan Li
      • Hengyang, China
        • Recruiting
        • The First Affiliated Hospital of University of South China
        • Contact:
          • Qin Tong
      • Hohhot, China
        • Recruiting
        • Affiliated Hospital of Inner Mongolia Medical University
        • Contact:
          • Caixia Liu
      • Jiangmen, China
        • Recruiting
        • Jiangmen Central Hospital
        • Contact:
          • Xiaoping Li
      • Jinan, China
        • Recruiting
        • Shandong Cancer Hospital
        • Contact:
          • Huihui Li
      • Jining, China
        • Recruiting
        • Affiliated Hospital of Jining Medical University
        • Contact:
          • Changping Shan
      • Kunming, China
        • Not yet recruiting
        • Yunnan Cancer Hospital
        • Contact:
          • Jianyun Nie
      • Lanzhou, China
        • Recruiting
        • The First Hospital of Lanzhou University
        • Contact:
          • Xiaoling Ling
      • Lanzhou, China
        • Not yet recruiting
        • Gansu Provincial Cancer Hospital
        • Contact:
          • Yingxia Tian
      • Linyi, China
        • Not yet recruiting
        • LinYi Cancer Hospital
        • Contact:
          • Jingfen Wang
      • Linyi, China
        • Not yet recruiting
        • Linyi people's hospital
        • Contact:
          • Guixiang Weng
        • Principal Investigator:
          • Guixiang Weng
        • Principal Investigator:
          • Zhongmin Zhang
      • Luoyang, China
        • Recruiting
        • The First Affiliated Hospital of Henan University of Science and Technology
        • Contact:
          • Xinshuai Wang
      • Meizhou, China
        • Recruiting
        • Meizhou People's Hospital
        • Contact:
          • Jingna Wu
      • Nanchang, China
        • Recruiting
        • The Third Hospital of Nanchang
        • Contact:
          • Zhihua Li
      • Nanchang, China
        • Recruiting
        • Jiangxi Provincial Cancer Hospital
        • Contact:
          • Xiaoming Zhong
      • Nanjing, China
        • Recruiting
        • Jiangsu Provincial Cancer Hospital
        • Contact:
          • Yuan Yuan
      • Nanjing, China
        • Not yet recruiting
        • Jiangsu Provincial People's Hospital
        • Contact:
          • Yongmei Yin
      • Nanning, China
        • Not yet recruiting
        • Guangxi Zhuang Autonomous Region People's Hospital
        • Contact:
          • Yanyan Xie
      • Nanning, China
        • Not yet recruiting
        • Cancer Hospital Affiliated to Guangxi Medical University
        • Contact:
          • Weimin Xie
        • Principal Investigator:
          • Weimin Xie
        • Principal Investigator:
          • Li Nong
      • Neijiang, China
        • Recruiting
        • The Second People's Hospital of Neijiang
        • Contact:
          • Xujuan Wang
      • Qingdao, China
        • Not yet recruiting
        • Affiliated Hospital of Qingdao University
        • Contact:
          • Wenfeng Li
      • Shanghai, China
        • Not yet recruiting
        • Fudan University Cancer Hospital
        • Contact:
          • Jian Zhang
      • Shantou, China
        • Not yet recruiting
        • Cancer Hospital Affiliated to Shantou University School of Medicine
        • Contact:
          • De Zen
      • Shaoguan, China
        • Recruiting
        • The People's Hospital of Northern Guangdong
        • Contact:
          • Zhan Huang
      • Shengyang, China
        • Recruiting
        • Liaoning Cancer Hospital
        • Contact:
          • Tao Sun
      • Suining, China
        • Recruiting
        • Suining Central Hospital
        • Contact:
          • Hongwei Yang
      • Suzhou, China
        • Not yet recruiting
        • The Second Affiliated Hospital of Soochow University
        • Contact:
          • Guoqin Jiang
      • Taiyuan, China
        • Not yet recruiting
        • Shanxi Provincial Cancer Hospital
        • Contact:
          • Fuguo Tian
      • Taiyuan, China
        • Not yet recruiting
        • Shanxi Bethune Hospital
        • Contact:
          • Jinnan Gao
      • Taizhou, China
        • Recruiting
        • Zhejiang Taizhou Hospital
        • Contact:
          • Bojian Xie
      • Tianjin, China
        • Recruiting
        • Tianjin Cancer Hospital
        • Contact:
          • Xuchen Cao
      • Wuhan, China
        • Not yet recruiting
        • Zhongnan Hospital of Wuhan University
        • Contact:
          • Hanjun Yu
      • Wuhan, China
        • Not yet recruiting
        • Union Hospital, Tongji Medical College, Huazhong University of Science and Technology
        • Contact:
          • Yanxia Zhao
      • Wuhan, China
        • Recruiting
        • Hubei Provincial Cancer Hospital
        • Contact:
          • Xinhong Wu
      • Wuhan, China
        • Not yet recruiting
        • People's Hospital of Wuhan University
        • Contact:
          • Feng Yao
      • Xi'an, China
        • Recruiting
        • The Second Affiliated Hospital of Xi'an Jiaotong University
        • Contact:
          • Shuqun Zhang
      • Xi'an, China
        • Not yet recruiting
        • The First Affiliated Hospital of Xi'an Jiaotong University
        • Contact:
          • Jin Yang
      • Xiamen, China
        • Recruiting
        • The First Affiliated Hospital of Xiamen University
        • Contact:
          • Zhong Ouyang
      • Xiangyang, China
        • Not yet recruiting
        • Xiangyang Central Hospital
        • Contact:
          • Yuehua Wang
      • Xining, China
        • Recruiting
        • Affiliated Hospital of Qinghai University
        • Contact:
          • Jiuda Zhao
      • Xinxiang, China
        • Recruiting
        • The First Affiliated Hospital of Xinxiang Medical University
        • Contact:
          • Liuzhong Yang
      • Xuzhou, China
        • Recruiting
        • Xuzhou Central Hospital
        • Contact:
          • Xiang Wang
      • Xuzhou, China
        • Not yet recruiting
        • Affiliated Hospital of Xuzhou Medical University
        • Contact:
          • Zhengqiu Zhu
      • Yongzhou, China
        • Recruiting
        • Yongzhou Central Hospital in Hunan Province
        • Contact:
          • Sijuan Ding
      • Zhaoqing, China
        • Recruiting
        • The First People's Hospital of Zhaoqing
        • Contact:
          • Jinhui Ye
      • Zhengzhou, China
        • Not yet recruiting
        • the First Affiliated Hospital of Zhengzhou University
        • Contact:
          • Hong Zong
      • Zhengzhou, China
        • Recruiting
        • Henan Provincial Cancer Hospital
        • Contact:
          • Min Yan
      • Zunyi, China
        • Recruiting
        • The Affiliated Hospital of Zunyi Medical University
        • Contact:
          • Taolang Li
      • Ürümqi, China
        • Recruiting
        • Affiliated Tumor Hospital of Xinjiang Medical University
        • Contact:
          • Bing Zhao
    • Guangdong
      • Guangzhou, Guangdong, China
        • Not yet recruiting
        • Erwei Song
        • Contact:
          • Erwei Song
    • Shanghai Municipality
      • Shanghai, Shanghai Municipality, China
        • Not yet recruiting
        • Jiong Wu
        • Contact:
          • Jiong Wu

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 1. The subject is able to understand the informed consent form, voluntarily participate and sign the informed consent form.

    2. The subject ≥ 18 years old on the day of signing the informed consent form, male or female.

    3. Unresectable locally recurrent or metastatic breast cancer, previous histopathological reports of HER2 IHC 1+ or 2+ and ISH-, previous histopathological reports have not been diagnosed as HER2 IHC 3+ or 2+ and ISH+.

    4. Have received at least 1 to 2 lines of chemotherapy regimens for breast cancer in the relapse/metastatic stage.

    5. Willing to provide sufficient archived tumor pathology specimens for central laboratory detection of HER2 status.

    6. Documented radiographic disease progression (during or after the most recent treatment).

    7. At least one extracranial measurable lesion at baseline according to RECIST 1.1 criteria.

    8. Expected survival ≥ 3 months. 9. ECOG score of 0 or 1 within 14 days prior to administration. 10. Female subjects of childbearing potential or male subjects of fertile partner consent to use highly effective contraception from the signing of informed consent.

    11. Laboratory tests within 14 days before administration and cardiac function tests within 28 days meet the criteria.

    12. Have sufficient elution of previous treatment before administration.

Exclusion Criteria:

  • 1. Untreated, or unstable brain parenchymal metastases, spinal cord metastases or compression, cancerous meningitis.

    2. Patients with only skin lesions as target lesions. 3. Those with a history of other primary malignant tumors within 5 years before administration.

    4. Selection of the control drug by the investigator who is not suitable for the protocol prescribed.

    5. Previous use of antibody conjugates containing topoisomerase I inhibitors. 6. There is a third gap fluid that cannot be controlled by drainage, etc. 7. Previous or current interstitial pneumonia/lung disease requiring systemic hormone therapy.

    8. Inability to swallow, chronic diarrhea, intestinal obstruction, or other factors that affect oral administration and absorption of the drug.

    9. Previous or current autoimmune disease. 10. Have uncontrolled comorbidities. 11. The toxicity of previous antitumor therapy has not been restored to grade ≤1 (NCI-CTCAE v5.0).

    12. History of previous immunodeficiency. 13. History of life-threatening allergic reactions or known ≥ grade 3 allergy to any component or excipient in the investigational pharmaceutical formulation.

    14. Other conditions that the investigators believe will affect the safety or adherence to drug treatment in this study, including but not limited to psychiatric disorders, alcohol or drug abuse.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: JSKN003
Administered intravenously according to protocol.
Drug: JSKN003
Administered intravenously according to protocol.
Active Comparator: The chemotherapy chosen by the investigator
The mono-chemotherapy drugs selected by the investigators included capecitabine, gemcitabine, vinorelbine, docetaxel, albumin-bound paclitaxel, or eribulin. The option should be determined before randomization.
Drug: Capecitabine tablets
Administered according to protocol, as one option for investigator's choice (determined before randomization).
Drug: Gemcitabine hydrochloride for injection
Administered according to protocol, as one option for investigator's choice (determined before randomization).
Drug: Vinorelbine tartrate injection
Administered according to protocol, as one option for investigator's choice (determined before randomization).
Drug: Paclitaxel for injection (albumin-bound type)
Administered according to protocol, as one option for investigator's choice (determined before randomization).
Drug: Docetaxel injection
Administered according to protocol, as one option for investigator's choice (determined before randomization).
Drug: Eribulin mesylate injection
Administered according to protocol, as one option for investigator's choice (determined before randomization).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Progression Free Survival (PFS)
Time Frame: up to approximately 3 years after the first enrollment
PFS evaluated by BICR according to RECIST v1.1 criteria is defined as the time from randomization to the first recorded disease progression or death from any cause as a result of BICR evaluation according to RECIST v1.1 criteria.
up to approximately 3 years after the first enrollment

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Overall survival（OS）
Time Frame: up to approximately 3 years after the first enrollment
OS, defined as the time from randomization to death from any cause;
up to approximately 3 years after the first enrollment
Objective Response Rate (ORR)
Time Frame: up to approximately 3 years after the first enrollment
BICR and investigators were judged according to RECIST v1.1 criteria ，objective response rate (ORR), defined as the proportion of participants achieving a complete response (CR) or partial response (PR) according to RECIST v1.1 criteria;
up to approximately 3 years after the first enrollment
Duration of Response (DOR)
Time Frame: up to approximately 3 years after the first enrollment
BICR and investigators were judged according to RECIST v1.1 criteria，Duration of response (DoR), defined as the time from the first recorded response (CR/PR) to the first documented disease progression (PD) or death from any cause;
up to approximately 3 years after the first enrollment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Jiangsu Alphamab Biopharmaceuticals Co., Ltd

Investigators

  • Principal Investigator: Erwei Song, Sun Yat-sen Memorial Hospital of Sun Yat-sen University
  • Principal Investigator: Jiong Wu, Fudan University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

December 1, 2023

Primary Completion (Estimated)

April 1, 2026

Study Completion (Estimated)

March 1, 2029

Study Registration Dates

First Submitted

September 22, 2023

First Submitted That Met QC Criteria

October 6, 2023

First Posted (Actual)

October 12, 2023

Study Record Updates

Last Update Posted (Estimated)

September 12, 2025

Last Update Submitted That Met QC Criteria

September 8, 2025

Last Verified

September 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • JSKN003-302

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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