NTRK1 and neoplasm: Several approved treatment options exist for TRK fusion-positive tumors, eg, larotrectinib and entrectinib, which are both tumor-agnostic first-generation TRK inhibitors.22 Larotrectinib is a highly selective and potent inhibitor that prevents activation of the kinase domain of all tropomyosin receptor kinase (TRK) proteins (A, B, and C) and the downstream signaling of MAPK and PI3K pathways.