A166 for HER2-positive advanced or metastatic breast cancer
Official title: Phase 2 Study of A166 in HER2-positive Metastatic Breast Cancer Patients Who Were Previously Treated With TOP1-ADCs
Run by Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. · NCT07299825 · Data updated 2026-11-12
This trial will test whether A166 helps adults with HER2-positive unresectable or metastatic breast cancer who previously received a topoisomerase inhibitor–based HER2 antibody-drug conjugate.
Quick facts
| Phase | Phase 2 |
|---|---|
| Study type | Interventional |
| Ages | 18 Years to 75 Years |
| Sex | All |
| Enrollment | 40 (estimated) |
| Sponsor | Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. Industry-sponsored |
| Drugs / interventions | trastuzumab |
| Locations | 1 site (Zhenzhou, Henan) |
| Status | Recruiting |
| Started | September 20, 2024 |
| Main results expected | September 20, 2027 |
| Study ends | December 31, 2027 |
| Registry record updated | May 8, 2026 |
| Trial ID | NCT07299825 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Adults aged 18–75 with histologically confirmed HER2-positive unresectable or metastatic breast cancer, at least one measurable lesion, prior treatment including a HER2 ADC with a topoisomerase inhibitor payload, and up to five prior systemic therapy lines are ideal candidates.
✕Probably not a fit
Patients previously treated with A166 or with prior HER2 ADCs carrying a microtubule inhibitor payload, those with severe baseline corneal epithelial disease, or those who had to permanently stop trastuzumab for toxicity are unlikely to benefit from this trial.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This Phase 2 interventional trial gives intravenous A166 every three weeks to adults with HER2-positive unresectable or metastatic breast cancer who have progressed after prior therapy, including at least one HER2 ADC with a topoisomerase inhibitor payload. Eligible patients are 18–75 years old, have measurable disease by RECIST 1.1, and have received no more than five prior lines of systemic therapy. Key exclusions include prior A166 or any HER2-directed ADC with a microtubule inhibitor payload, severe hypersensitivity to monoclonal antibodies, permanent discontinuation of trastuzumab for toxicity, or significant corneal epithelial disease. The study will measure anti-tumor activity and clinical outcomes on a schedule of Q3W IV dosing at a single lead site in Henan, China.
Why it matters
Potential benefit: If successful, A166 could shrink tumors or delay disease progression in patients whose cancer progressed after prior HER2-targeted ADCs with topoisomerase inhibitors.
How similar studies have gone: Other HER2-targeted ADCs (for example trastuzumab deruxtecan) have shown strong activity in HER2-positive breast cancer, but the benefit of a new ADC like A166 after prior TOP1-ADC exposure is less well established.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: 1. Male or female patient ≥ 18 years and ≤ 75 years when signing the informed consent form. 2. Breast cancer patients by histopathology and/or cytology documented. 3. In the advanced or metastatic stage, having received no more than 5 lines of systemic therapy, one of which must include a HER2 ADC with a topoisomerase inhibitor payload. 4. Patients must have experienced disease progression or intolerance during or after the most recent treatment prior to randomization. 5. At least one measurable lesion according to RECIST 1.1 criteria. Exclusion Criteria: 1. Previous treatment with A166 or any HER2-targeted antibody-drug conjugate (ADC) with a microtubule inhibitor payload. 2. Known history of severe hypersensitivity to other monoclonal antibodies, or allergy to A166 or their components. 3. Permanent discontinuation of trastuzumab or its biosimilars due to any toxicity in prior treatments. 4. Presence of severe corneal epithelial disease at baseline; or inability to perform daily activities without contact lenses. 5. Presence of spinal cord compression or clinically active central nervous system (CNS) metastases. 6. Other conditions considered by the investigator to make the patient unsuitable for participation in the study.
Where it's running
-
Henan Provincial Cancer Hospital
Zhenzhou, Henan, China Recruiting
Study contacts
- Study coordinator: Min Yan, Professor
- Email: ym200678@126.com
- Phone: 0371-65588404
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Other studies for the same condition or treatment. Recruiting studies are listed first.
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.