Recruiting

A Study to Investigate Mechanisms of Resistance to Breast Cancer Therapies

This study will evaluate mechanisms of resistance to anti-breast cancer therapies in tumor and blood samples from participants with human epidermal growth factor receptor (HER2) positive, hormone receptor (HR) positive or triple negative breast cancer.

ClinicalTrials.gov IDNCT06274515

PhasePHASE4

Enrollment320

SponsorHoffmann-La Roche

Age18 Years

SexALL

I'm interested View official listing

Conditions studied

Breast Cancer

About this study

Interventions

Procedure: Tumor Tissue and Blood Draw — Participants will have their blood drawn on the day a tissue sample is taken from a progressive tumor lesion.

Primary outcomes

Changes from baseline in HER2 protein levels measured at the time of disease progression/recurrence (Cohorts H1 and H2) (At least 6 months)
Changes from baseline in HER2 gene copy number measured at the time of disease progression/recurrence (Cohorts H1 and H2) (At least 6 months)
Changes from baseline in estrogen receptor (ER) protein levels measured at the time of disease progression/recurrence (Cohorts H1 and H2) (At least 6 months)
Changes from baseline in HER2 protein levels measured at the time of disease progression/recurrence (Cohort H3) (Less than 6 months)
Changes from baseline in HER2 gene copy number measured at the time of disease progression/recurrence (Cohort H3) (Less than 6 months)
Changes from baseline in ER protein levels measured at the time of disease progression/recurrence (Cohort H3) (Less than 6 months)
Changes from baseline in genes related to CDK4/6 resistance (incl. cell cycle alterations and tyrosine kinase receptors, Cohort R1) (At least 6 months)
Changes from baseline in genes related to endocrine resistance (incl. cell cycle alterations and tyrosine kinase receptors, Cohort R1) (At least 6 months)

Eligibility information

General Inclusion Criteria: * Willingness to undergo a procedure to obtain tumor tissue (e.g. biopsy) and blood draw * Diagnosis of HER2+, HR+ (for cohort R1) or triple negative breast cancer (for cohort T1) as per local assessment * Availability of an archival tumor tissue (most recent pre-treatment tumor tissue is preferred) * Unequivocally growing tumor lesion (progressive lesion) that is accessible for resection, excision or core needle biopsy * Discontinuation of prior anti-cancer treatment outlined below should not be longer than 4 weeks from participation in this study Inclusion criteria for participants in the cohorts studying acquired resistance * Participant had undergone regular monitoring for disease progression as per local practice (preferably every 3-6 months) while on most recent breast cancer therapy * Accessible tumor lesion that newly appeared or a lesion that started to regrow while the participant was at least 6 months on therapy Inclusion criteria for participants in the cohort studying primary resistance * Accessible tumor lesion that continued to increase in size or a newly appearing lesion (as confirmed by routine tumor assessment) while treated for at least 4 weeks but less than 6 months on therapy Exclusion Criteria: * Any risks factors that increase the risk of complications associated with the procedure to obtain tumor tissue (e.g. bleeding disorders) * Any serious medical condition or abnormality in clinical laboratory tests that precludes an individual's safe participation in and completion of the study * Participant has started treatment with subsequent anti-cancer therapy * Participants whose progressive tumor lesion that is targeted for biopsy/resection is in the bone * Discontinuation of treatment was due to a reason other than disease progression

Study locations

Institut Jules Bordet, Anderlecht, 1070 Belgium
AZ KLINA, Brasschaat, 2930 Belgium
CHU de Liège (Sart Tilman), Liège, 4000 Belgium
AZ Delta (Campus Rumbeke), Roeselare, 8800 Belgium
Aalborg Universitetshospital, Aalborg, 9000 Denmark
Sjællands Universitetshospital, Næstved, Næstved, 4700 Denmark
Helsinki University Central Hospital, Helsinki, 00029 Finland
Tampere University Hospital, Tampere, 33520 Finland
St. Elisabeth Krankenhaus Köln GmbH, Cologne, 50935 Germany
KEM/Evang. Kliniken Essen Mitte gGmbH, Essen, 45136 Germany

Showing 10 of 28 reported sites. See the official listing for all locations.

Before you participate: Varda Clinical is an independent discovery tool, not the study sponsor or a medical provider. Eligibility can only be determined by the official study team. Discuss potential risks and benefits with a qualified healthcare professional.

Source: ClinicalTrials.gov. Record last refreshed by Varda Clinical: 2026-09-27.