Real-World Treatment of ADC-Resistant HER2-Low Advanced Breast Cancer

May 8, 2026 updated by: The First Affiliated Hospital with Nanjing Medical University

Optimal Treatment Strategies for ADC-Resistant HER2-Low Advanced Breast Cancer: A Multicenter, Retrospective Real-World Study

This is a multicenter, retrospective real-world study aiming to evaluate the efficacy and safety of post-antibody-drug conjugate (post-ADC) treatment strategies in patients with HER2-low advanced breast cancer who have developed resistance to prior ADC therapy. The study plans to enroll approximately 220 eligible patients from three centers in China (Jiangsu Province Hospital, Nanjing Drum Tower Hospital, and Nanjing General Hospital of Nanjing Military Command) between January 2018 and December 2025. Key efficacy outcomes include progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and clinical benefit rate (CBR). Safety outcomes include the incidence of grade 3/4 adverse events and serious adverse events. Subgroup analyses will compare different post-ADC regimens (e.g., alternative ADC, chemotherapy, endocrine therapy, immunotherapy) and explore the impact of visceral metastasis and prior ADC treatment response on subsequent outcomes. This study seeks to identify optimal post-ADC treatment strategies and preferred patient populations for clinical benefit.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
220

Contacts and Locations

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

Study Locations

  • China
    • Jiangsu
      • Nanjing, Jiangsu, China, 210029
        • The First Affiliated Hospital with Nanjing Medical University

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

Patients with histologically confirmed HER2-low advanced or metastatic breast cancer who received antibody-drug conjugate (ADC) therapy in the advanced setting and subsequently experienced disease progression.

Description

Inclusion Criteria:

  • females aged ≥18 years.
  • confirmed pathologic diagnosis of HER2-low MBC (defined as HER2 IHC 1+ or 2+ without gene amplification by FISH detection).
  • patients had disease progression following ADC treatment in advanced setting and had undergone at least one available efficacy evaluation.
  • patients received at least one subsequent anti-tumor treatment following ADC failure, with at least one available efficacy evaluation.

Exclusion Criteria:

  • patients previously treated with ADC during neoadjuvant or adjuvant setting.
  • patients who had not experienced disease progression on their first ADC (ADC1) regimen and remained on ADC1 treatment.
  • patients with no documented subsequent anti-tumor therapy following ADC1 treatment.
  • patients who lacked evaluable efficacy assessment data during ADC1 or post-ADC therapy.
  • patients with incomplete clinicopathological information.

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

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
real-world (rwPFS) of post-ADC therapy
Time Frame: up to 12 months.
the duration from the post-ADC treatment initiation to either disease progression or death from any cause, whichever came first
up to 12 months.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
objective response rate (ORR)
Time Frame: at 12 weeks
ORR was defined as the percentage of patients achieving a best overall response of complete response (CR) or partial response (PR).
at 12 weeks
Clinical benefit rate (CBR) of post-ADC therapy
Time Frame: at 12 weeks
CBR was determined by the percentage of patients achieving disease control, defined as complete response (CR), partial response (PR), or stable disease (SD).
at 12 weeks
overall survival (OS) of post-ADC therapy
Time Frame: up to 24 months
Overall survival was defined as the duration from post-ADC treatment initiation to death from any cause.
up to 24 months

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
The First Affiliated Hospital with Nanjing Medical 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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 1, 2018

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 14, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 8, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 14, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 14, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2026-SR-247

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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