Editor’s Note: The treatment of HER2-positive breast cancer remains a focal point in clinical research. At the 2024 San Antonio Breast Cancer Symposium (SABCS), a phase 1b study led by Dr. Biyun Wang from Fudan University Shanghai Cancer Center presented promising results (Abstract No. P5-05-02). This study explored the pharmacokinetics and preliminary efficacy of a novel HER2 antibody-drug conjugate (ADC), GQ1001, combined with pyrotinib in patients with HER2-positive metastatic breast cancer (MBC) who had undergone prior treatments. Here, we provide an overview of this groundbreaking research.

Oncology Frontier: Prof. Wang, could you summarize the highlights of your team’s research?

Dr. Biyun Wang: This investigator-initiated trial (IIT) from our center garnered significant attention at this year’s SABCS, sparking discussions among domestic and international experts.

GQ1001, developed by Keymed Biosciences using the iLDC technology platform, represents a next-generation HER2 ADC. Its global studies have demonstrated strong safety and efficacy across various HER2-positive solid tumors.

In this study, we combined GQ1001 with pyrotinib to treat patients with HER2-positive advanced breast cancer who had previously been treated with trastuzumab. The results were highly encouraging:

• Efficacy: Among the 15 enrolled patients, the objective response rate (ORR) was 80%. This included one patient achieving complete response (CR). Notably, four patients remained on treatment for over a year, and one patient has been on the regimen for nearly two years, continuing to benefit.
• Safety: The combination therapy demonstrated a favorable safety profile with no new toxicities reported.

These findings suggest that this regimen holds promise for addressing unmet treatment needs, particularly in patients who have developed resistance to other HER2 ADC therapies like trastuzumab deruxtecan (T-DXd). Moving forward, we aim to enroll more patients exposed to HER2-DXd to explore the potential of GQ1001 in this population.

Dr. Biyun Wang

• Director of the Department of Medical Oncology (Breast and Genitourinary Oncology), Fudan University Shanghai Cancer Center
• Chief Physician and Master’s Supervisor
• Executive Member of the Chinese Society of Clinical Oncology (CSCO)
• Chair of the CSCO Youth Committee
• Secretary-General of the CSCO Patient Education Expert Committee
• Member of the CSCO Breast Cancer Expert Committee
• Chair of the CRPC Committee, Shanghai Anti-Cancer Association
• Standing Committee Member, Breast Cancer Professional Committee, Shanghai Anti-Cancer Association

Chengcheng Gong

• Medical Oncologist, Fudan University Shanghai Cancer Center
• Graduate of Fudan University Shanghai Medical College
• First author of several SCI-indexed publications
• Presenter at multiple international and national conferences
• Principal investigator of four research grants
• Member and Secretary, CSCO Youth Committee
• Youth Member, Breast Professional Committee, Chinese Female Physicians Association
• Secretary-General, Multidisciplinary Breast Tumor Committee, Shanghai Society of Private Healthcare Institutions