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QuantifyHER: Quantitative Immunofluorescence and/or RT-qPCR for Measuring HER2 in HER2-low Metastatic Breast Cancer

This study will assess whether a quantitative, HER2 assay can accurately and reliably discriminate between responders and non-responders among patients with HER2 IHCI+ metastatic breast cancer who are receiving T-Dxd.

ClinicalTrials.gov IDNCT06551116
PhaseNot Applicable
Enrollment200
SponsorAbramson Cancer Center at Penn Medicine
Age18 Years
SexALL
I'm interested View official listing

Conditions studied

HER2-positive Metastatic Breast Cancer

About this study

This study will assess whether a quantitative, HER2 assay can accurately and reliably discriminate between responders and non-responders among patients with HER2 IHCI+ metastatic breast cancer who are receiving T-Dxd.

Interventions

Primary outcomes

Eligibility information

Inclusion Criteria: * Women and men age \> 18 years * Metastatic breast cancer, histologically- confirmed. Any estrogen receptor (ER) status is allowed. ER status will be determined by local laboratory assessment utilizing ASCO/CAP guidelines. * Primary and/or metastatic tumor with 1+ level of expression of HER2 by immunohistochemistry as determined by local laboratory assessment utilizing ASCO/CAP guidelines. * Measurable disease by cross-sectional imaging at the start of treatment. Patients with measurable bone-only disease or active brain metastases are eligible. * Archival tissue available for biomarker assessment. One specimen should be the most recent metastatic biopsy. If HER2 1+ status was determined on a different specimen (either primary or metastatic tissue), that specimen is also required. Samples obtained from bone metastases that were processed via decalcification methods are not eligible. * Intention to initiate therapy with T-DXd (Enhertu) at FDA-approved dose and schedule as next line of therapy. If T-DXd was already initiated, patients must be registered within 30 days of initiation. * Ability to provide informed consent Exclusion Criteria: * Concurrent Her2-overexpressing metastatic breast cancer (as confirmed by a metastatic biopsy with IHC 3+ or IHC 2+ with FISH amplified as per standard ASCO/CAP guidelines)

Study locations

Showing 10 of 37 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.