Her 2 Positive Breast CancerPhase 2NCT07299825
A Study of A166 in Patients With HER2-Positive Unresectable or Metastatic Breast Cancer
A Phase 2 study testing A166 in people with Her 2 Positive Breast Cancer, run by Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. at 1 site in China.
Trial summary
Evaluation of the efficacy of A166 in Patients with HER2-Positive unresectable or metastatic breast cancer previously treated with TOP1 inhibitor Antibody-Drug Conjugates Read more about this study
- Who is it for?
- Ages 18 to 75 years
- Conditions the study is for
- Her 2 Positive Breast Cancer
- What is being tested?
- A166
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteChina
- Study dates
- 20 Sep 2024to 31 Dec 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Male or female patient ≥ 18 years and ≤ 75 years when signing the informed consent form.
- Breast cancer patients by histopathology and/or cytology documented.
- 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.
- Patients must have experienced disease progression or intolerance during or after the most recent treatment prior to randomization.
- At least one measurable lesion according to RECIST 1.1 criteria.
Who cannot join
- Previous treatment with A166 or any HER2-targeted antibody-drug conjugate (ADC) with a microtubule inhibitor payload.
- Known history of severe hypersensitivity to other monoclonal antibodies, or allergy to A166 or their components.
- Permanent discontinuation of trastuzumab or its biosimilars due to any toxicity in prior treatments.
- Presence of severe corneal epithelial disease at baseline; or inability to perform daily activities without contact lenses.
- Presence of spinal cord compression or clinically active central nervous system (CNS) metastases.
- Other conditions considered by the investigator to make the patient unsuitable for participation in the study.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
China1 site, 1 recruiting
- Recruiting
Henan Provincial Cancer Hospital
Zhenzhou, Henan, 450000
Min Yan, Professor, 037165588404, ym200678@126.com
About this study
Official title: Phase 2 Study of A166 in HER2-positive Metastatic Breast Cancer Patients Who Were Previously Treated With TOP1-ADCs
Evaluation of the efficacy of A166 in Patients with HER2-Positive unresectable or metastatic breast cancer previously treated with TOP1 inhibitor Antibody-Drug Conjugates
Read the detailed description
This study will evaluate the efficacy of A166 in patients with HER2-positive unresectable or metastatic breast cancer previously treated with TOP1 inhibitor Antibody-Drug Conjugates.
A166 will be administered every 3 weeks (Q3W) intravenous (IV) infusion.
- Conditions
- Her 2 Positive Breast Cancer
- Being tested
- A166
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
A166Drug
intravenous(IV) infusion (Q3W)
| Study group | Role | What they receive |
|---|---|---|
| A166 | Experimental | A166 is administered intravenously at a dose of 4.8 mg/kg every 21 (±3) days (q3w). Receives: Drug: A166 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Objective response rate(ORR)
ORR is defined as the percentage of patients who achieve complete response(CR) or partial response (PR), as assessed by investigator per RECIST 1.1
Measured: Within 24 months of last patient enrolled
Secondary outcomes (5)
Progression-free survival (PFS)
PFS, 6-month PFS, 12-month PFS.PFS as assessed by investigator according to RECIST v 1.1
Measured: Within 24 months of last patient enrolled
Overall survival (OS)
OS, 1-year survival rate, 1.5-year survival rate, and 2-year survival rate.OS defined as time from inclusion until death
Measured: Within 48 months of last patient enrolled
Disease control rate(DCR)
DCR is defined as the percentage of patients who achieve CR, PR or stable disease (SD), as assessed by investigator per RECIST 1.1
Measured: Within 24 months of last patient enrolled
Duration of response(DOR)
DoR is defined as the time from the date of first documented CR or PR until date of documented disease progression per RECIST 1.1, as assessed by investigator or death due to any cause, whichever occurs first.
Measured: Within 24 months of last patient enrolled
Clinical Benefit Rate (CBR)
CBR is defined as a patient having a best overall response of a complete response (CR), partial response (PR), or stable disease for at least 6 months.
Measured: Within 24 months of last patient enrolled
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Dec 2025
- Study start20 Sep 2024
- Primary completion20 Sep 2027 (estimated)
- Study completion31 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Her 2 Positive Breast CancerStudies of the same condition, open and under way.
- More trials run by Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd.The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07299825
- Sponsor's protocol ID
- KL166-II-08
- Status last verified
- May 2026
- First submitted
- 3 Dec 2025
- Last updated
- 8 May 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 8 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Phase 2 Study of A166 in HER2-positive Metastatic Breast Cancer Patients Who Were Previously Treated With TOP1-ADCs
- ClinicalTrials.gov ID
- NCT07299825
- Acronym / sponsor ID
- KL166-II-08
- Conditions
- Her 2 Positive Breast Cancer
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd.Industry (pharma, biotech, devices)
- Study start
- 20 Sep 2024 (actual)
- Primary completion
- 20 Sep 2027 (estimated)
- Study completion
- 31 Dec 2027 (estimated)
- First posted
- 23 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Evaluation of the efficacy of A166 in Patients with HER2-Positive unresectable or metastatic breast cancer previously treated with TOP1 inhibitor Antibody-Drug Conjugates
Detailed description
This study will evaluate the efficacy of A166 in patients with HER2-positive unresectable or metastatic breast cancer previously treated with TOP1 inhibitor Antibody-Drug Conjugates.
A166 will be administered every 3 weeks (Q3W) intravenous (IV) infusion.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| A166 | Experimental | Drug: A166A166 is administered intravenously at a dose of 4.8 mg/kg every 21 (±3) days (q3w). |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Male or female patient ≥ 18 years and ≤ 75 years when signing the informed consent form.
- Breast cancer patients by histopathology and/or cytology documented.
- 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.
- Patients must have experienced disease progression or intolerance during or after the most recent treatment prior to randomization.
- At least one measurable lesion according to RECIST 1.1 criteria.
Key exclusion criteria (6 listed)
- Previous treatment with A166 or any HER2-targeted antibody-drug conjugate (ADC) with a microtubule inhibitor payload.
- Known history of severe hypersensitivity to other monoclonal antibodies, or allergy to A166 or their components.
- Permanent discontinuation of trastuzumab or its biosimilars due to any toxicity in prior treatments.
- Presence of severe corneal epithelial disease at baseline; or inability to perform daily activities without contact lenses.
- Presence of spinal cord compression or clinically active central nervous system (CNS) metastases.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| A166intravenous(IV) infusion (Q3W) | Drug | A166 |
Primary outcome
Objective response rate(ORR)
Time frame: Within 24 months of last patient enrolled
ORR is defined as the percentage of patients who achieve complete response(CR) or partial response (PR), as assessed by investigator per RECIST 1.1
5 secondary outcomes
Progression-free survival (PFS)
Time frame: Within 24 months of last patient enrolled
Overall survival (OS)
Time frame: Within 48 months of last patient enrolled
Disease control rate(DCR)
Time frame: Within 24 months of last patient enrolled
Duration of response(DOR)
Time frame: Within 24 months of last patient enrolled
Clinical Benefit Rate (CBR)
Time frame: Within 24 months of last patient enrolled
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 May 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing A166 in people with Her 2 Positive Breast Cancer, run by Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 8 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Min Yan, Professor (0371-65588404, ym200678@126.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Objective response rate(ORR) (time frame: Within 24 months of last patient enrolled). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 May 2026.