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CASE REPORT article

Front. Oncol.
Sec. Breast Cancer
Volume 14 - 2024 | doi: 10.3389/fonc.2024.1444431

Case Report: Prolonged Benefit of ESG401, a Trop2 Antibody-Drug Conjugate, in Endocrine-Refractory Hormone Receptor-Positive, HER-2 Negative Metastatic Breast Cancer

Provisionally accepted
Jing Zhao Jing Zhao 1Fengbo Huang Fengbo Huang 1Xia Xu Xia Xu 2Yan Zhang Yan Zhang 1Xiaoyan Xing Xiaoyan Xing 3Jian Huang Jian Huang 1*Fuming Qiu Fuming Qiu 1*
  • 1 Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
  • 2 Jinhua Central Hospital, Jinhua, Zhejiang Province, China
  • 3 Shanghai Escugen Biotechnology Co., Ltd,, Shanghai, China

The final, formatted version of the article will be published soon.

    Breast cancer (BC) remains a leading cause of cancer-related mortality in women, with hormone receptor-positive (HR+) tumors accounting for a significant proportion of cases. Despite advancements in endocrine therapy (ET), resistance remains a challenge in metastatic settings. The use of cyclin-dependent kinases 4/6 (CDK4/6) inhibitors in combination with endocrine therapy has notably improved survival. In China, when patients develop resistance to CDK4/6 inhibitors (CDK4/6i) or face financial constraints that prevent their use, chemotherapy becomes the standard treatment approach. This highlights an urgent need for effective treatments following CDK4/6i therapy. ESG401 is a novel trophoblast cell-surface antigen 2 (Trop2) directed antibody-drug conjugate (ADC) with promising preclinical and early clinical efficacy and safety data. We report a case of a 61-year-old female with HR+HER2-metastatic breast cancer (MBC) who developed resistance to fulvestrant and subsequent chemotherapy but achieved a durable partial response (PR) lasting more than 22.5 months following ESG401 treatment. This case underscores the potential role of Trop2-directed ADCs, such as ESG401, in overcoming endocrine resistance and providing meaningful clinical benefit in heavily pretreated patients with HR+/HER2-MBC. Furthermore, the patient's exceptionally long clinical benefit distinguishes her from other patients receiving ESG401 treatment. Further exploration of the use of ESG401 in HR+HER2-MBC patients, as well as a deeper understanding of the characteristics of patients that may impact sustained efficacy, in expanded clinical trials is warranted.

    Keywords: Hormone receptor-positive, metastatic breast cancer, Endocrine resistance, Trop2 antibody-drug conjugate, case report

    Received: 05 Jun 2024; Accepted: 12 Nov 2024.

    Copyright: © 2024 Zhao, Huang, Xu, Zhang, Xing, Huang and Qiu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Jian Huang, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
    Fuming Qiu, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China

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