NCT06551116 · Abramson Cancer Center at Penn Medicine
QuantifyHER: Quantitative Immunofluorescence and/or RT-qPCR for Measuring HER2 in HER2-low Metastatic Breast Cancer
What this study is about
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.
View original scientific description
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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
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)
Where
- San Francisco, California
- Derby, Connecticut
- Fairfield, Connecticut
- Glastonbury, Connecticut
- Greenwich, Connecticut
- Guilford, Connecticut
- Hartford, Connecticut
- New Haven, Connecticut
- Stamford, Connecticut
- Torrington, Connecticut
- Trumbull, Connecticut
- Waterbury, Connecticut
And 18 more locations — see the full list below.
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 8, 2026 · Source of record for eligibility and locations