Evaluation of [68Ga]Ga-NOTA-anti-HER2-sdAb PET/CT for Predicting Pathological Complete Response After Neoadjuvant Chemotherapy in HER2 Positive Early Breast Cancer (GATHER)

July 22, 2026 updated by: Centre Henri Becquerel

Evaluation of [68Ga]Ga-NOTA-anti-HER2-sdAb PET/CT for Predicting Pathological Complete Response After Neoadjuvant Chemotherapy in HER2 Positive Early Breast Cancer (GATHER): a Study Protocol for a Monocentric, Prospective, Interventional, Phase 2, Imaging Biomarker Trial.

The GATHER trial aim to evaluate the diagnostic performance of [68Ga]Ga-NOTA-anti-HER2-sdAb PET/CT in predicting pCR following neoadjuvant chemotherapy. This study is part of the development of new functional, non-invasive approaches with the aim of offering personalized therapeutic approaches.

Study Overview

Status

Status

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

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.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

In early-stage HER2-positive breast cancer, neoadjuvant chemotherapy is frequently required, and pathological complete response (pCR) correlates with excellent prognosis. However, no non-invasive imaging method reliably predicts pCR, making surgery mandatory despite its aesthetic, functional, and psychological burden. Recently, new functional imaging tracers targeting the HER2 protein have been developed. Among these, [68Ga]Ga-NOTA-anti-HER2-sdAb is of particular interest due to its molecular characteristic; it has demonstrated favorable safety profile and ability to identify HER2+ cells in vivo. This trial evaluates its ability to predict pCR, with the prospect of paving the way for future therapeutic de escalation and surgical sparing.

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.
Interventional

Enrollment (Estimated)

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.
42

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

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

Description

Inclusion Criteria:

  • Female aged 18 years or older
  • Histologically proven HER2-positive early breast cancer, defined as IHC 3+ or IHC 2+ with ISH amplification
  • Indication for neoadjuvant chemotherapy combined with anti-HER2 targeted therapy followed by surgery, as determined by a multidisciplinary tumor board
  • ECOG performance status of 0 or 1
  • Affiliated to or beneficiary of a social protection scheme
  • Written informed consent signed prior to any study-specific procedure

Exclusion Criteria:

  • Pregnant or breastfeeding women

    • Patient not treated with curative intent
    • History of ipsilateral breast cancer treated by surgery and/or radiotherapy
    • Lobular histology
    • Known contraindication or hypersensitivity to [68Ga]Ga-NOTA-anti-HER2-sdAb or any of its radiopharmaceutical excipients
    • Known contraindication or hypersensitivity to [18F]F-FDG or any of its radiopharmaceutical excipients
    • Concurrent enrollment in another clinical trial evaluating radiopharmaceuticals
    • Patient under guardianship, curatorship, or judicial protection
    • Patient deprived of liberty
    • Inability to understand the study or comply with trial constraints due to linguistic, psychological, or geographical barriers

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

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: [68Ga]Ga-NOTA-anti-HER2-sdAb Positron Emission Tomography
Patients will undergo an [68Ga]Ga-NOTA-anti-HER2-sdAb PET/CT before neoadjuvant chemotherapy and 15 days prior the scheduled surgery
Other: [68Ga]Ga-NOTA-anti-HER2-sdAb Positron Emission Tomography
Patients will undergo an [68Ga]Ga-NOTA-anti-HER2-sdAb PET/CT before neoadjuvant chemotherapy and 15 days prior the scheduled surgery

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
Concordance rate between the response estimated by [68Ga]Ga-NOTA-anti-HER2-sdAb PET/CT and the invasive pathological complete response
Time Frame: 2 weeks after surgery
The concordance rate is defined as the proportion of patients correctly classified by the post-therapeutic PET/CT compared to the gold standard histopathological assessment (ypT0/is ypN0).
2 weeks after surgery

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
Concordance rate between the response estimated by [68Ga]Ga-NOTA-anti-HER2-sdAb PET/CT and the pCR on both invasive and non-invasive components
Time Frame: two weeks after surgery
The concordance rate is calculated as the proportion of correctly classified patients compared to the non-invasive pCR definition (ypT0 ypN0), in addition to the invasive definition (ypT0/is ypN0)
two weeks after surgery
Comparison of the diagnostic performance of [68Ga]Ga-NOTA-anti-HER2-sdAb PET/CT against other conventional imaging modalities in predicting the invasive pCR
Time Frame: Two weeks after surgery
ΔSUV is defined as the relative change in SUVmax between the baseline and post-therapeutic [68Ga]Ga-NOTA-anti-HER2-sdAb PET/CT, compared according to invasive pathological complete response (ypT0/is ypN0).
Two weeks after surgery

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.
Centre Henri Becquerel

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Florian Clatot, MD, PhD, Centre Henri Becquerel

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.
July 15, 2026

Primary Completion (Estimated)

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.
September 1, 2027

Study Completion (Estimated)

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.
March 1, 2028

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).
May 12, 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 12, 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 18, 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.
July 23, 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.
July 22, 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.
July 1, 2026

More Information

Terms related to this study

Keywords

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.
  • CHB25.04
  • 2025-523286-23-00 (Ctis)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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