The Food and Drug Administration  has approved Roche’s Ventana ALK (D5F3) CDx assay, a companion diagnostic that determines whether patients with non-small cell lung cancer (NSCLC) are eligible for treatment with Novartis’ Zykadia (ceritinib). The test works by detecting the presence of the anaplastic lymphoma kinase (ALK) protein, a biomarker associated with cancer pathogenesis, in formalin-fixed, paraffin-embedded stained NSCLC tissue. Patients who are ALK-positive might benefit from treatment with Zykadia, which acts as an ALK-inhibitor and potentially shrinks tumors. The Ventana ALK diagnostic also determines whether patients can be treated with Xalkori (crizotinib), another ALK inhibitor.