HER2 TREAT Study: Retrospective Study to Estimate the Prevalence of HER2-low in Unresectable and/or Metastatic Breast Cancer Patients Who Progress on Anti-Cancer Therapy Identified as HER2-Negative From Patient Medical Records in The Gulf Cooperation Council

September 18, 2025 updated by: AstraZeneca

A Multicenter, Non-Interventional, Retrospective Study Aims to Estimate the Prevalence and Describe the Clinical Manifestations of HER2-Low Breast Cancer Reported in Unresectable and/or Metastatic Breast Cancer Patients Who Progress on Anti-Cancer Therapy Identified as HER2- Negative From Patient Medical Records in The Gulf Council Cooperation Region

HER2-low Breast cancer (BC) has emerged as a new subtype of BC with distinct clinical, pathological, and prognostic features. Little is known about the prevalence of the HER2-low subtype in HER2-negative patients, and previous reports showed variations in the criteria used to define the HER2-low subtype. Besides, data on the clinical features and prognosis of HER2-low patients are limited, and it is still unclear whether HER2-low BC has a prognostic value. Identifying the prevalence and clinical features of HER2-low BC can help establish a more accurate and reproducible definition of HER2-low BC. In the Gulf Cooperation Council (GCC) region, BC is the most common malignancy in women and still poses a significant burden on healthcare resource utilization, moreover, there is only one record for reimbursed HER2 IHC status, categorized as HER2-positive and HER2-negative. It is important to understand the prevalence, clinical features, and outcomes of HER2-low in BC patients from the GCC In this retrospective, non-interventional, multicenter study, the aim to describe the prevalence of HER2-low BC among the current HER2-negative BC population using rescored HER2 IHC samples. The local treatment patterns and the outcomes will be analyzed using the information abstracted from the corresponding medical chart review. The study will cover the GCC region countries (United Arab Emirates [UAE], Saudi Arabia, Qatar, Kuwait, and Oman)

Study Overview

Status

Completed

Conditions

Study Type

Observational

Enrollment (Actual)

517

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

  • Kuwait
      • Kuwait City, Kuwait
        • Research Site
  • Qatar
      • Doha, Qatar
        • Research Site
  • Saudi Arabia
      • Riyadh, Saudi Arabia
        • Research Site
    • Saudi Arabia
      • Makkah al Mukarramah, Saudi Arabia, Saudi Arabia
        • Research Site
  • United Arab Emirates
      • Abu Dhabi, United Arab Emirates
        • Research Site
      • Al Ain City, United Arab Emirates
        • Research Site
      • Dubai, United Arab Emirates
        • Research Site

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

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult (aged > 18 years old) patients with a confirmed diagnosis of HER2-negative (assessed preferably by Ventana 4b5 assay) Unresectable and/or mBC who presented to the participating centers within the period from 1st January 2018 to 31st December 2022 and who are diagnosed and/or progressed on at least one prior systemic anti-cancer therapy (Endocrine therapy, chemotherapy, CDK4/6i, targeted therapies other than anti-HER2, or PDL1 inhibitor) , regardless of their hormonal status.

Description

Inclusion Criteria:

  • women ≥ 18 years of age at date of diagnosis
  • Patients must have a histological or cytological confirmed diagnosis of Unresectable or/and mBC between 01st January 2018 and 31st December 2022.
  • Patients with at least 12 months of follow-up data (from the index date) in the medical records at the participating site unless patient died.
  • Patients must have been diagnosed as HER2-negative (HER2 IHC 0, 1+, 2+/ISH-), regardless of hormone status.
  • Patients who are diagnosed and/or progressed on at least one prior systemic anticancer therapy (e.g., ET, chemotherapy, CDK4/6i, targeted therapies other than anti- HER2, or immunotherapy) in the metastatic setting.
  • Patients must have historical HER2 fixed tissue IHC stained slides in acceptable quality to allow retesting of HER2 expression only in case of the absence of accurate scoring of IHC/ISH in pathology report.

Exclusion Criteria:

  • Have a history of other malignancies other than basal cell carcinoma of the skin and squamous cell carcinoma of the skin.
  • Patients who are HER2 positive (with historical HER2 status of IHC 2+/ISH+ or 3+, or HER2 amplified.

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

Outcome Measure
Time Frame
HER2-low prevalence based on rescoring of historical HER2 fixed tissue slides among HER2-negative Unresectable or/and metastatic Breast Cancer patients.
Time Frame: 1st January 2018 to 31st December 2022
1st January 2018 to 31st December 2022

Collaborators and Investigators

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

Sponsor

AstraZeneca

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

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)

March 5, 2024

Primary Completion (Actual)

September 30, 2024

Study Completion (Actual)

September 30, 2024

Study Registration Dates

First Submitted

November 6, 2023

First Submitted That Met QC Criteria

November 6, 2023

First Posted (Actual)

November 9, 2023

Study Record Updates

Last Update Posted (Estimated)

September 23, 2025

Last Update Submitted That Met QC Criteria

September 18, 2025

Last Verified

September 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • D133FR00197

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal Vivli.org. All requests will be evaluated as per the AZ disclosure commitment: https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

IPD Sharing Time Frame

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA/PhRMA Data-Sharing Principles. For details of our timelines, please refer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure

IPD Sharing Access Criteria

When a request has been approved AstraZeneca will provide access to the anonymized individual patient-level data via secure research environment Vivli.org. A Signed Data Usage Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • CSR

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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