Roche has received FDA approval for the PATHWAY HER2 (4B5) test as a companion diagnostic to identify patients with previously-treated, unresectable, or metastatic HER2-positive biliary tract cancer (BTC) who may be eligible for treatment with Jazz Pharmaceuticals' ZIIHERA (zanidatamab-hrii). This approval marks a significant advancement in personalized medicine for BTC, a cancer with limited treatment options and poor prognosis.
The PATHWAY HER2 (4B5) test is designed to assess HER2-positive status in BTC patients, helping clinicians determine if they are likely to respond to HER2-targeted therapy. HER2, a receptor protein expressed in various cancers, serves as a predictive biomarker. Until now, no approved and validated HER2 test existed specifically for identifying eligible BTC patients.
Clinical Significance
"This test is a step forward in furthering access to personalised medicine," said Jill German, Head of Pathology Lab at Roche Diagnostics. "The prognosis for patients diagnosed with BTC is poor, as very few treatment options exist. Now, these patients have access to the first standardised test that could make them eligible for targeted therapy, potentially improving clinical outcomes."
ZIIHERA is the first FDA-approved treatment for adults with previously-treated, unresectable, or metastatic HER2-positive (IHC 3+) biliary tract cancer. The approval of the PATHWAY HER2 (4B5) test will help ensure that ZIIHERA is used in the appropriate patient population, maximizing its potential benefit.
Disease Burden and Unmet Need
BTC accounts for approximately 3% of all gastrointestinal cancers in the US. The prognosis for BTC patients is generally poor due to a lack of early detection tools, challenging anatomical access, aggressive tumor biology, and limited effectiveness of systemic treatments. Most cases are diagnosed at an advanced stage, with five-year overall survival rates of only 19% for localized disease and 3% for cancer that has spread to other areas.
About the PATHWAY HER2 (4B5) Test
The PATHWAY anti-HER2/neu (4B5) Rabbit Monoclonal Primary Antibody test provides clear and reliable results, aiding in therapeutic decisions. It is already indicated for identifying breast cancer patients eligible for HER2-targeted treatments like Herceptin, KADCYLA, or ENHERTU. The test is used with the fully automated VENTANA BenchMark slide staining instrument.
The assay standardizes all immunohistochemistry (IHC) processes, reducing the possibility of human error and minimizing variability. The Roche HER2 (4B5) clone achieves consistently high proficiency assessment scores and demonstrates high concordance with HER2 FISH, empowering laboratories to employ a reliable HER2 IHC primary antibody.
