Two first-generation TRK inhibitors, Larotrectinib (LOXO-101) [6] and Entrectinib (RXDX-101) [7], were approved by the U.S. Food and Drug Administration (FDA) in 2018 and 2019, respectively [8], for the treatment of TRK fusion-positive adult and pediatric cancers. The gene discussed is NTRK1; the disease is cancer.