Loxo Oncology has teamed with Ventana Medical Systems, a member of the Roche Group, to develop and commercialize a pan-tropomyosin receptor kinase (TRK) immunohistochemistry (IHC) test. This companion diagnostic will be used to identify patients across tumor types suitable for treatment with larotrectinib, which is an investigational drug in clinical development for patients with cancers that harbor abnormalities involving TRKs. Under the terms of the partnership, Roche will use its flagship OptiView DAB detection technology to develop further an investigational TRK IHC assay piloted by Loxo Oncology. Initially, the parties will optimize and validate the assay to ensure it is sufficiently robust to withstand clinical and regulatory scrutiny. The collaboration then plans to globally commercialize an analytical version of the assay, followed by the development of a Class III assay that will be submitted to the Food and Drug Administration (FDA) for premarket approval. FDA approval will be based on analyses of patient samples collected from Loxo Oncology’s ongoing larotrectinib clinical trials.