New hope for Hard-to-Treat breast cancer: drug targets even low HER2 levels
NCT ID NCT05950945
First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This phase 3 trial is testing trastuzumab deruxtecan (T-DXd), a drug that delivers chemotherapy directly to cancer cells with a specific marker (HER2). It includes 250 people with advanced breast cancer that has low or even no HER2, which is often harder to treat. Participants receive the drug every three weeks, and researchers will track how long it takes before they need a different treatment.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- trastuzumab deruxtecan (T-DXd, Enhertu)
- What this could lead to
- If successful, this could provide a new treatment option for people with advanced breast cancer that has low or no HER2 protein, potentially delaying the need for other therapies.
- What could go wrong
- This is an open-label study without a placebo group, so results may be less definitive. Side effects from T-DXd can include lung inflammation, nausea, and low blood counts.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 3
Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.
- Participants
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About 250 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Dec 2023
- Expected to finish
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Oct 2027
An estimate. End dates often move.
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 years and older
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Sign and date the main informed consent form * Must agree to provide a newly obtained or archival baseline biopsy from primary and/or metastatic lesion. * Pathologically documented Breast Cancer (BC) tumor * Is unresectable and/or metastatic. * Is hormone receptor-negative or hormone receptor-positive. * Must include percentage of positively stained cells to characterize if hormone receptor-positive or -negative. * Has confirmed HER2 IHC 1+ or IHC 2+/ISH- (HER2-low) status or HER2 IHC 0 status as determined according to ASCO CAP 2018 guidelines1 based on sample collected during Tissue Screening as described above. * Was never previously HER2-positive (IHC 3+ or IHC 2+/ISH+) on prior pathology testing (per ASCO CAP guidelines). * Was never previously treated with anti-HER2 therapy in the metastatic setting. * Has had at least one and up to two prior lines of therapy in the metastatic setting. * In participants with hormone receptor-positive HER2-low metastatic BC (Cohort 3): * Has recurrent disease \<2 years from the initiation of adjuvant ET OR * Has disease progression on CDK4/6 inhibitor-based regimen within 12 months of completion of adjuvant therapy with a CDK4/6 inhibitor OR * Has disease progression within the first 12 months of CDK4/6 in the first line metastatic setting * Presence of at least one measurable lesion based on computed tomography or magnetic resonance imaging. * Participants with brain metastases are allowed in the study. The brain lesion(s) should be small (\<2 cm), untreated, asymptomatic, not requiring urgent medical intervention, and are asymptomatic and clinically stable. * Has an Eastern Cooperative Oncology Group performance status of 0 or 1. * Has a minimum life expectancy of 12 weeks at Screening. * Has a left ventricular ejection fraction ≥50% within 28 days before enrollment. * Has adequate organ and bone marrow function within 28 days before enrollment. * Has adequate treatment washout period before enrollment. * Male and female subjects of reproductive/childbearing potential must agree to use a highly effective form of contraception. Exclusion Criteria: * Prior treatment with an antibody drug conjugate (ADC). * Uncontrolled or significant cardiovascular disease. * Has a corrected QT interval prolongation. * Has a history of (non-infectious) interstitial lung disease (ILD)/pneumonitis that required steroids, has current ILD/pneumonitis, or where suspected ILD/pneumonitis cannot be ruled out by imaging at Screening. * Has spinal cord compression or clinically active central nervous system metastases. * Has multiple primary malignancies within 3 years, except adequately resected non-melanoma skin cancer, curatively treated in situ disease, other solid tumors curatively treated, or contralateral BC. * Has a history of severe hypersensitivity reactions to either the drug substances or inactive ingredients in the drug product. * Has a history of severe hypersensitivity reactions to other monoclonal antibodies. * Has an uncontrolled infection requiring intravenous (IV) antibiotics, antivirals, or antifungals. * Active primary immunodeficiency, known uncontrolled active human immunodeficiency virus (HIV) infection, or active hepatitis B or C infection. * Has history of receiving a live, attenuated vaccine (messenger RNA and replication-deficient adenoviral vaccines are not considered attenuated live vaccines) within 30 days prior to the first exposure to study drug. * Has unresolved toxicities from previous anticancer therapy, defined as toxicities (other than alopecia) not yet resolved to Grade ≤1 or baseline. * Is pregnant or breastfeeding or planning to become pregnant. * Lung-specific intercurrent clinically significant illnesses. * Any autoimmune, connective tissue, or inflammatory disorders. * Prior complete pneumonectomy.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The study's own enquiry address
This study publishes an address for enquiries. See it below .
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The places running it
68 sites in 9 countries. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Show contact details
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Study contacts
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Contact
Email: •••••@•••••
Locations
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307 Hospital of PLA
RECRUITINGBeijing, 100161, China
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Alrijne Ziekenhuis Leiden
RECRUITINGLeiden, 2334, Netherlands
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Amphia Ziekenhuis Molengracht
RECRUITINGBreda, 4818 CK, Netherlands
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Amsterdam UMC, Locatie VUMC
RECRUITINGAmsterdam, 1081 HV, Netherlands
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Anhui Provincial Cancer Hospital
RECRUITINGHefei, 230031, China
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Azienda Ospedaliera Universitaria Policlinico Sant Orsola Malpighi IRCCS
RECRUITINGBologna, 40138, Italy
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Azienda Ospedaliera Universitaria Policlinico Umberto I - Università di Roma La Sapienza
RECRUITINGRome, 00161, Italy
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Beaumont Hospital
RECRUITINGDublin, Dublin 9, Ireland
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Beijing Hospital
RECRUITINGBeijing, 100006, China
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Bernhoven Uden
RECRUITINGUden, 5406, Netherlands
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Beth Israel Lahey Health
WITHDRAWNBurlington, Massachusetts, 01805, United States
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CEPHO - Centro de Estudos e Pesquisas de Hematologia e Oncologia
RECRUITINGSanto André, 09060-650, Brazil
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CEPON - Centro de Pesquisas Oncológicas de Santa Catarina
RECRUITINGFlorianópolis, 88034-000, Brazil
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CIONC-Centro Integrado de Oncologia de Curitiba
RECRUITINGCuritiba, 80810-050, Brazil
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Catarina Pesquisa Clinica
RECRUITINGSanta Catarina, 88301-220, Brazil
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Centre Hospitalier Universitaire de Liege Sart-Tilman
WITHDRAWNLiège, 4000, Belgium
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Centro Hospitalar de Lisboa Norte E P E Hospital de Santa Maria
RECRUITINGLisbon, 1649-028, Portugal
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Centro de Oncologia - Unidade Brasília - Hospital Sírio Libanês
RECRUITINGBrasília, 71635-610, Brazil
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Clinica Universidad de Navarra
RECRUITINGPamplona, 31008, Spain
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Cliniques Universitaires Saint-Luc
WITHDRAWNBrussels, 1200, Belgium
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Clínica de Pesquisas e Centro de Estudos em Oncologia Ginecológica e Mamária Ltda
RECRUITINGSão Paulo, 01317-001, Brazil
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Complejo Hospitalario Universitario Insular Materno-Infantil
RECRUITINGLas Palmas de Gran Canaria, 35016, Spain
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Complejo Hospitalario Universitario de Santiago
RECRUITINGSantiago de Compostela, 15706, Spain
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Cork University Hospital
RECRUITINGCork, T12 EC8P, Ireland
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Dana-Farber Cancer Institute
RECRUITINGBoston, Massachusetts, 02215, United States
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Elisabeth TweeSteden Ziekenhuis
RECRUITINGTilburg, 5022 GC, Netherlands
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Ensino e Terapia de Inovação Clínica AMO-ETICA
RECRUITINGSalvador, 41810-570, Brazil
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Fiona Stanley Hospital
WITHDRAWNMurdoch, 6150, Australia
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Fondazione Policlinico Universitario Agostino Gemelli IRCCS
RECRUITINGRome, 00168, Italy
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Fudan University Shanghai Cancer Center
RECRUITINGShanghai, 200032, China
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Fujian Cancer Hospital
RECRUITINGFujian, 350011, China
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Fundacao Faculdade Regional de Medicina de Sao Jose do Rio Preto
RECRUITINGSão José do Rio Preto, 15090-000, Brazil
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Fundação Champalimaud
RECRUITINGLisbon, 1400-038, Portugal
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Fundação Doutor Amaral Carvalho
RECRUITINGJaú, 17.210 - 080, Brazil
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GZA Ziekenhuizen
WITHDRAWNAntwerp, 2610, Belgium
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GZA Ziekenhuizen
RECRUITINGWilrijk, 2610, Belgium
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Galway University Hospital
WITHDRAWNGalway, H91 YR71, Ireland
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GenesisCare St Andrews Hospital
TERMINATEDAdelaide, 5000, Australia
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Haga Ziekenhuis
RECRUITINGThe Hague, 2545 AA, Netherlands
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Henan Cancer Hospital
RECRUITINGZhengzhou, 450008, China
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Hospital Arnau de Vilanova de Valencia
RECRUITINGValencia, 46015, Spain
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Hospital Beata Maria Ana
RECRUITINGMadrid, 28007, Spain
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Hospital Clinico Universitario de Valencia
RECRUITINGValencia, 46010, Spain
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Hospital Erasto Gaertner - Liga Paranaense de Combate ao Câncer
RECRUITINGCuritiba, 81520-060, Brazil
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Hospital General Universitario Morales Meseguer
RECRUITINGMurcia, 30008, Spain
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Hospital Nossa Senhora da Conceicao
RECRUITINGRio Grande, 88701-160, Brazil
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Hospital Universitario 12 de Octubre
RECRUITINGMadrid, 28041, Spain
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Hospital Universitario Donostia
WITHDRAWNDonostia / San Sebastian, 20014, Spain
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Hospital Universitario Puerta de Hierro Majadahonda
RECRUITINGMajadahonda, 28222, Spain
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Hospital Universitario Virgen Macarena
RECRUITINGSeville, 41009, Spain
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Hospital Universitario Virgen de las Nieves
RECRUITINGGranada, 18014, Spain
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Hospital das Clínicas FMRP-USP
RECRUITINGRiberão Preto, 14015-010, Brazil
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Hospital de Braga
RECRUITINGBraga, 4710-243, Portugal
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Hospital de la Santa Creu i Sant Pau
RECRUITINGBarcelona, 08025, Spain
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Humanitas Istituto Clinico Catanese
RECRUITINGMisterbianco, 95045, Italy
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ICESP - Instituto do Câncer do Estado de São Paulo Octavio Frias de Oliveira
RECRUITINGSão Paulo, 01246-000, Brazil
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ICO l'Hospitalet - Hospital Duran i Reynals
RECRUITINGBarcelona, 08908, Spain
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IOV - Istituto Oncologico Veneto IRCCS
RECRUITINGPadova, 35128, Italy
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Institut Jules Bordet
RECRUITINGAnderlecht, 1070, Belgium
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Instituto Português de Oncologia de Lisboa Francisco Gentil, EPE
WITHDRAWNLisbon, 1099-023, Portugal
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Instituto Português de Oncologia do Porto Francisco Gentil, EPE
WITHDRAWNPorto, 4200-072, Portugal
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Instituto de Cancer de Londrina
RECRUITINGLondrina, 86015-520, Brazil
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Istituto Nazionale Tumori Fondazione G Pascale
RECRUITINGNaples, 80131, Italy
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Istituto Nazionale per la Ricerca sul Cancro di Genova
RECRUITINGGenova, 16132, Italy
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Istituto Tumori Giovanni Paolo II IRCCS Ospedale Oncologico Bari
WITHDRAWNBari, 70124, Italy
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Jiangxi Cancer Hospital
RECRUITINGNanchang, 330029, China
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Maastricht University Medical Center
RECRUITINGMaastricht, 6229 HX, Netherlands
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Mater Hospital Sydney
TERMINATEDNorth Sydney, New South Wales, 2065, Australia
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Medisch Centrum Leeuwarden
RECRUITINGLeeuwarden, 8934 AD, Netherlands
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Monash Medical Centre Moorabbin
TERMINATEDEast Bentleigh, Victoria, 3165, Australia
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Mount Sinai Medical Center
TERMINATEDMiami Beach, Florida, 33140, United States
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Nanchang People's Hospital
RECRUITINGNanchang, 330006, China
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Nuovo Ospedale di Prato
RECRUITINGPrato, 59100, Italy
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Oncosite - Centro de Pesquisa Clinica e Oncologia
RECRUITINGIjuí, 98700-000, Brazil
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Ospedale San Raffaele
RECRUITINGMilan, 20132, Italy
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Ospedale Santa Chiara
RECRUITINGTrento, 38123, Italy
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Overlook Medical Center
RECRUITINGSummit, New Jersey, 07901, United States
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Shandong Cancer Hospital
RECRUITINGJinan, 250117, China
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St James Hospital
RECRUITINGDublin, D08 NHY1, Ireland
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St Vincent's University Hospital
RECRUITINGDublin, D04 T6F4, Ireland
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Sun Yat sen University Cancer Center
RECRUITINGGuangzhou, 510060, China
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The Affiliated Hospital of Qingdao University
WITHDRAWNQingdao, 266000, China
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USF College of Medicine
WITHDRAWNTampa, Florida, 33602, United States
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UZ Leuven
WITHDRAWNLeuven, 3000, Belgium
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Universitair Ziekenhuis Brussel
WITHDRAWNBrussels, 1090, Belgium
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Xijing Hospital (The First Affiliated Hospital of the Air Force Medical University)
WITHDRAWNXi'an, 710032, China
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Yunnan Cancer Hospital
WITHDRAWNKunming, 650107, China
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Zhejiang Cancer Hospital
RECRUITINGHangzhou, 310022, China
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