Blood-Based Assay Detects HER2 Mutations to Guide NSCLC Treatment

Non-small cell lung cancer (NSCLC) is the most common form of lung cancer, and a subset of patients harbor HER2 (ERBB2) mutations that may be addressed with precision therapies. These HER2‑mutant tumors are aggressive and have been associated with a poor prognosis. Because tissue sampling can be difficult in advanced disease, blood-based testing offers a faster, less invasive alternative. A newly approved companion diagnostic now uses a liquid biopsy to identify adults with HER2‑mutant advanced NSCLC who are eligible for a targeted therapy.

Guardant Health’s Guardant360 CDx has received U.S. Food and Drug Administration (FDA) approval as a companion diagnostic for Boehringer Ingelheim’s HERNEXEOS (zongertinib tablets), recognized as the first targeted therapy for adults with HER2 (ERBB2)-mutant advanced NSCLC as an initial treatment option. The approval enables the blood-based assay to identify patients with HER2 tyrosine kinase domain activating mutations who may be eligible for treatment with HERNEXEOS. The test expands access to biomarker-driven therapy selection using a simple blood draw.

Guardant360 CDx is a liquid biopsy that analyzes circulating tumor DNA from a blood sample, detecting tumor-derived alterations in circulating cell-free DNA. By providing comprehensive genomic profiling across multiple tumor types and biomarkers, the assay helps clinicians match patients to appropriate targeted therapies and clinical trials. The approach can be advantageous when tissue biopsy is infeasible or delayed in advanced disease.

HERNEXEOS is indicated for adult patients with unresectable or metastatic non-squamous NSCLC whose tumors harbor HER2 tyrosine kinase domain activating mutations, as detected by an FDA‑authorized test. The indication was granted under accelerated approval based on objective response rate and duration of response, with continued approval contingent upon confirmatory evidence of clinical benefit. This latest FDA decision represents the 27th companion diagnostic indication for Guardant360 CDx across multiple tumor types globally, and the test is broadly covered by Medicare and commercial payers representing more than 300 million covered lives.

Guardant360 CDx was the first FDA‑approved liquid biopsy for comprehensive genomic profiling. The assay detects multiple genomic alterations across all solid tumors. It is also approved as a companion diagnostic for therapies in NSCLC, breast cancer, and colorectal cancer.

“This approval highlights the growing impact of liquid biopsy across advanced cancer care and underscores the utility of Guardant360 CDx to ensuring more patients can be matched to the right therapy at the right time,” said Helmy Eltoukhy, Guardant Health chairman and co-CEO. “Guardant360 CDx has been at the forefront of enabling comprehensive genomic profiling through a simple blood draw, helping clinicians identify actionable mutations in genes such as HER2 with speed and accuracy.”

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