Guardant Health and Merck announced a multi‑year partnership to develop and commercialize companion diagnostics using Guardant’s portfolio of liquid and tissue biopsy assays to support patient enrollment in Merck’s global clinical studies. The agreement prioritizes streamlined patient identification for targeted therapies and aims to integrate circulating tumor DNA testing into trial workflows. Companies said the collaboration will accelerate precision‑medicine enrollment and potentially expand use of minimally invasive diagnostics across Merck’s oncology programs.