Guardant Health said the FDA approved Guardant360 CDx as a companion diagnostic for Boehringer Ingelheim’s Hernexeos (zongertinib) in adults with HER2-mutant advanced non-small cell lung cancer. The liquid biopsy assay is intended to identify HER2 tyrosine kinase domain activating mutations and support treatment selection. This marks the 27th companion diagnostic indication for Guardant360 CDx and extends the assay’s footprint across solid tumor biomarker-driven care. The approval is described as accelerated, based on objective response rate and duration of response. Clinically, the update tightens the diagnostics-to-treatment pathway by pairing a specific blood-based test with a targeted therapy, which can improve access for patients who cannot readily obtain adequate tissue samples.