Roche has received FDA approval for the PATHWAY HER2 (4B5) test as a companion diagnostic to identify biliary tract cancer (BTC) patients who may benefit from 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 now the first and only FDA-approved companion diagnostic for identifying HER2-positive BTC patients eligible for HER2-targeted therapy.
Significance of the Approval
Biliary tract cancer accounts for 3% of all gastrointestinal cancers in the US. The prognosis for BTC patients is generally poor, with a five-year overall survival rate of only 19% for localized disease and 3% for cancer that has spread. This is largely due to late diagnosis and limited effective treatment options. HER2, a receptor protein, is expressed in various cancers and serves as a predictive biomarker for HER2-targeted therapies. Prior to this approval, no validated HER2 test existed to identify eligible BTC patients.
"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."
About the PATHWAY HER2 (4B5) Test
The PATHWAY anti-HER2/neu (4B5) Rabbit Monoclonal Primary Antibody test is designed to deliver clear and reliable results, enabling informed therapeutic decisions. It standardizes immunohistochemistry (IHC) processes, reducing the potential for human error and minimizing variability. The Roche HER2 (4B5) clone demonstrates high concordance with HER2 FISH and achieves consistently high proficiency assessment scores. Previously, the test was indicated for identifying breast cancer patients eligible for HER2-targeted treatments like Herceptin, KADCYLA, or ENHERTU.
ZIIHERA (zanidatamab-hrii) and HER2 in BTC
ZIIHERA is the first FDA-approved treatment for adults with previously-treated, unresectable or metastatic HER2-positive (IHC 3+) biliary tract cancer. The companion diagnostic approval of the PATHWAY HER2 (4B5) test is crucial for identifying patients most likely to benefit from this targeted therapy. Studies have shown that HER2 amplification is present in a subset of BTC patients, making them potential candidates for HER2-directed treatments.
Implications for BTC Treatment
This approval represents a significant advancement in the management of biliary tract cancer. By providing a standardized and reliable method for identifying HER2-positive patients, the PATHWAY HER2 (4B5) test enables clinicians to make more informed treatment decisions and potentially improve outcomes for patients with this aggressive cancer.
