Using a more precise HER2 protein test to find breast cancer patients who could benefit from trastuzumab-deruxtecan

Research Project 1

NIH-funded research Washington University · NIH-11172474

This project looks at whether a more precise lab test for HER2 protein can identify breast cancer patients, including those called HER2-low or HER2-zero, who may benefit from the drug trastuzumab-deruxtecan (DS-8201a).

Quick facts

Grant typeNIH-funded research
Study typeNIH-funded research
Funding institutionWashington University NIH-funded
Lab location1 site (Saint Louis, United States)
Project IDNIH-11172474 on NIH RePORTER

What this research studies

Antibody-drug conjugates like trastuzumab-deruxtecan deliver chemotherapy directly to HER2-expressing cancer cells, and some patients classified as HER2-low or HER2-zero by standard IHC have still responded. The team will use a mass-spectrometry based CLIA assay (MRM-MS) that measures HER2 protein over a wider range than routine tests, running it on tumor samples. They will compare those quantitative HER2 levels with clinical responses to DS-8201a to see if the new test better predicts who benefits. The work aims to improve patient selection for this targeted chemotherapy and may involve sending samples to a certified lab or enrolling at participating centers.

Who could benefit from this research

Good fit: Ideal candidates are people with breast cancer classified as HER2-low or HER2 0 by routine IHC (IHC 0–2+/ISH-) who have available tumor tissue and are eligible for or have received DS-8201a treatment.

Not a fit: Patients whose tumors clearly lack HER2 protein by multiple testing methods or those with cancers unrelated to HER2-driven biology are unlikely to benefit from this HER2-targeted approach.

Why it matters

Potential benefit: If successful, the assay could help more accurately select breast cancer patients who are likely to benefit from trastuzumab-deruxtecan, potentially expanding treatment to some labeled HER2-low or HER2-zero.

How similar studies have performed: Trastuzumab-deruxtecan has shown benefit in clinical trials for HER2-positive and HER2-low breast cancers, but using a mass-spectrometry HER2 assay to predict response is a newer and relatively untested approach.

Where this research is happening

Saint Louis, United States

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.