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Observational study on HER2-low breast cancer treatment with Trastuzumab Deruxtecan

A Prospective, Non-interventional Study (NIS) With Trastuzumab Deruxtecan For Patients With HER2-low Expressing Unresectable and/or Metastatic Breast Cancer Accompanied By a Disease Registry of Patients Treated With Conventional Chemotherapy (DESTINY Breast Respond HER2-low Europe)

Daiichi Sankyo · NCT05945732

This study is testing how well Trastuzumab deruxtecan works for adults with advanced HER2-low breast cancer who have already had chemotherapy.

Quick facts

Study typeObservational
Enrollment1155 (estimated)
Ages18 Years and up
SexAll
SponsorDaiichi Sankyo (industry)
Drugs / interventionschemotherapy, Trastuzumab
Locations211 sites (Graz and 210 other locations)
Trial IDNCT05945732 on ClinicalTrials.gov

What this trial studies

This observational study aims to evaluate the effectiveness of Trastuzumab deruxtecan (T-DXd) in adult patients with unresectable or metastatic HER2-low breast cancer who have previously undergone chemotherapy. It will collect data on patient demographics, clinical characteristics, treatment patterns, tolerability, and management of adverse drug reactions. Patients will receive treatment according to the established guidelines without the administration of any additional drug products as part of the study. Additionally, data on conventional chemotherapy treatments will be gathered to enhance understanding of treatment outcomes.

Who should consider this trial

Good fit: Ideal candidates include adults aged 18 and older with confirmed unresectable or metastatic HER2-low breast cancer who have received prior chemotherapy.

Not a fit: Patients who are pregnant, breastfeeding, or currently participating in a blinded interventional study may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide valuable insights into the effectiveness and tolerability of T-DXd for patients with HER2-low breast cancer, potentially improving treatment options.

How similar studies have performed: While this study focuses on a specific patient population, similar approaches using targeted therapies in breast cancer have shown promise in previous studies.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Adult patient (age ≥ 18 years) with histological or cytological confirmed diagnosis of unresectable and/or mBC
* Documented HER2-low status (IHC1+, IHC2+/ISH-)
* Patients who have received prior chemotherapy in the metastatic setting or patients who have developed disease recurrence during or within 6 months of completing adjuvant chemotherapy
* Decision to newly initiate therapy of T-DXd or conventional chemotherapy according to the physicians choice per SmPC
* Written and signed Informed Consent to participate in the study

Exclusion Criteria:

* Pregnancy or breastfeeding
* Patients who at time of data collection for this study are participating in or have participated in an interventional study that remains blinded.

No other specific exclusion criteria are defined, as patients will be treated according to the proposed indication statements in the SmPC.

Where this trial is running

Graz and 210 other locations

+161 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Unresectable Breast Cancer, Metastatic Breast Cancer, HER2-low Expressing Breast Cancer, Trastuzumab Deruxtecan, Enhertu®

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.