The US Food and Drug Administration (FDA) has approved a label expansion for Roche’s PATHWAY anti-HER2/neu (4B5) Rabbit Monoclonal Primary Antibody test, into biliary tract cancer (BTC).

This approval marks the test as the first FDA-approved companion diagnostic to help identify biliary tract cancer (BTC) patients eligible for Jazz Pharmaceuticals' ZIIHERA (zanidatamab-hrii). 

Before this label expansion, no approved and validated HER2 test was available for identifying BTC patients suitable for such treatments.

Roche Diagnostics Pathology Lab head Jill German said: “This test is a step forward in furthering access to personalised medicine.

“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 has been approved by the FDA as the first therapy for adults with previously treated, unresectable or metastatic HER2-positive (IHC 3+) BTC.

Biliary tract cancers represent 3% of all gastrointestinal cancers in the US, often diagnosed at an advanced stage with a five-year overall survival rate of 19% when localised and only 3% when metastasised.

The PATHWAY anti-HER2/neu (4B5) test presents timely, clear, and reliable results, supporting therapeutic decisions.

Already utilised to determine breast cancer patients' eligibility for HER2-targeted treatments with Herceptin, Kadcyla, or Enhertu, it is compatible with the fully automated VENTANA BenchMark slide staining instrument.

The new indication for BTC significantly broadens the clinical utility of the test.

It is part of Roche's comprehensive gastrointestinal cancer solutions portfolio, designed to provide diagnostic certainty in cancer care.

The assay standardises immunohistochemistry (IHC) processes and minimises human error and inherent variability in manual and semi-automated IHC methods.

According to Roche, the HER2 (4B5) clone consistently achieves high proficiency assessment scores against other clones.