An observational study in HER2-positive Metastatic Breast Cancer, sponsored by Abramson Cancer Center at Penn Medicine. Recruiting at 37 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-08.
Sponsored by Abramson Cancer Center at Penn Medicine · Observational
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.
Abramson Cancer Center at Penn Medicine is the lead sponsor of 446 studies on the registry; 86 are open to participants now.
Of its 32 completed or terminated interventional studies of FDA-regulated products, 14 (44%) have results posted.
Counted across the registry records on this site, refreshed daily.
Patients with HER2 IHC1+ metastatic breast cancer, histologically confirmed
Exclusion Criteria:
Analysis of HER2 expression via QIF and mRNA assays
Diagnostic Test: CE-10-IVD
Leftover tumor tissue from a routine biopsy will be sent for analysis.
Real-World Objective Response Rate
Association between quantitative HER2 expression (as a continuous variable) and real-world objective response rate
Time frame: from date of first dose of T-DXd to date of last dose of T-DXd for each. Up to 100 months
Real-World Progression Free Survival
Association between quantitative HER2 expression (as a continuous variable) and real world Progression Free Survival
Time frame: from date of first dose of T-DXd to date of last dose of T-DXd for each.Up to 100 months
Real-World Progression Free Survival and Objective Response Rate by estrogen receptor expression
Association between HER2 expression by quantitative immunofluorescence and mRNA in HER2 IHC 1+ tumors and both rwORR and rwPFS, stratified by mRNA ER expression
Time frame: from date of first dose of T-DXd to date of last dose of T-DXd for each. Up to 100 months
Threshold for HER2 QIF and/or mRNA levels
cut-off value for HER2 QIF, mRNA and the combination below which patients will not respond to T-DXd."
Time frame: from date of first dose of T-DXd to date of last dose of T-DXd for each. Up to 100 months
Association between combined mRNA + QIF and real-world Objective Response Rate
Comparison, based on rwORR, of a linear combination of HER2 QIF and mRNA, versus either alone in ability to discriminate T-DXd responders from non- responders
Time frame: from date of first dose of T-DXd to date of last dose of T-DXd for each. Up to 100 months
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Abramson Cancer Center at Penn Medicine