Description: Larotrectinib, also known as ARRY-470 and LOXO-101, is an orally bioavailable, potent, ATP-competitive inhibitor of TRKA, TRKB, and TRKC. LOXO-101 has IC50 values in the low nanomolar range for inhibition of all three TRK family members in binding and cellular assays, with 100x selectivity over other kinases, and has shown acceptable pharmaceutical properties and safety in nonclinical models. The TRK family of neurotrophin receptors, TRKA, TRKB, and TRKC (encoded by NTRK1, NTRK2, and NTRK3 genes, respectively) and their neurotrophin ligands regulate growth, differentiation and survival of neurons.