Roche’s PATHWAY® HER2 and VENTANA® HER2 Dual ISH Companion Diagnostics Approved by FDA for ZIIHERA® Eligibility in HER2-Positive Metastatic Gastroesophageal Adenocarcinoma

August 30, 2026

BioSpace USA

Overview

Roche has received FDA approval for two companion diagnostic tests, PATHWAY® HER2 (4B5) and VENTANA® HER2 Dual ISH DNA Probe Cocktail, to identify patients with HER2-positive metastatic gastroesophageal adenocarcinoma (GEA) eligible for Jazz Pharmaceuticals’ ZIIHERA® (zanidatamab-hrii) therapy. These diagnostics are critical for accurately assessing HER2 status in GEA, which includes gastric, GE junction, and esophageal adenocarcinomas. This approval marks a significant step in advancing personalized medicine for GEA patients, ensuring targeted access to effective HER2-directed treatments.

In Depth

Key Findings

Roche has secured FDA approval for two crucial companion diagnostic tests, the PATHWAY® HER2 (4B5) antibody and the VENTANA® HER2 Dual ISH DNA Probe Cocktail. These diagnostics are designed to identify patients with HER2-positive metastatic gastroesophageal adenocarcinoma (GEA) who are eligible for treatment with Jazz Pharmaceuticals’ targeted therapeutic, ZIIHERA® (zanidatamab-hrii). This approval significantly broadens the diagnostic landscape for GEA, enabling clinicians to accurately determine HER2 status across gastric, gastroesophageal junction, and esophageal adenocarcinomas, thereby facilitating precision medicine.

Technical / Clinical Details

The PATHWAY® HER2 (4B5) utilizes immunohistochemistry (IHC) to detect HER2 protein overexpression, while the VENTANA® HER2 Dual ISH DNA Probe Cocktail employs a dual in situ hybridization (Dual ISH) method to identify HER2 gene amplification. These complementary assays provide a robust and precise assessment of HER2 status in tumor tissue. Accurate identification of HER2 overexpression or gene amplification is paramount for selecting patients most likely to respond to HER2-targeted therapies like ZIIHERA®. Given the aggressive nature and limited treatment options for GEA, optimizing patient selection through precise diagnostics is crucial for improving therapeutic outcomes.

Background & Context

ZIIHERA® is a monoclonal antibody specifically designed to target HER2, a protein frequently overexpressed or amplified in certain cancers. The approval of companion diagnostics is a cornerstone of modern oncology, ensuring that specific drugs are administered to patient populations where they are most likely to be effective, thereby minimizing ineffective treatments and unnecessary side effects. Roche’s recent FDA approval aligns with the broader industry trend towards precision medicine in oncology, where advanced biosensor technologies play a central role in accurate biomarker detection, forming the foundation for personalized cancer care.

Strategic Significance & Outlook

The availability of these companion diagnostics is expected to directly impact the treatment paradigm for HER2-positive GEA patients, particularly as ZIIHERA® becomes more widely available. Clinicians will now have validated tools to guide treatment decisions, maximizing the potential benefits for patients while optimizing resource allocation. This development is anticipated to lead to revisions in clinical guidelines for GEA management and could contribute to improved survival rates and quality of life for affected individuals. Furthermore, this precedent may accelerate the development and approval of similar companion diagnostics for other targeted therapies in the pipeline.

Source: https://www.biospace.com/press-releases/roche-receives-fda-approval-for-companion-diagnostic-tests-to-identify-patients-with-her2-positive-metastatic-gastroesophageal-adenocarcinoma-eligible-for-ziihera

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