Loxo Oncology, Inc., a biopharmaceutical company, develops and sells medicines for patients with genetically defined cancers in the United States. Its lead product candidate comprises larotrectinib, an oral selective inhibitor of tropomyosin receptor kinase (TRK), which is in adult Phase 1 trial, a pediatric Phase 1/2 trial, and an adult/adolescent Phase 2 trial for the treatment of patients with tumor types, such as lung, head and neck, melanoma, colorectal, sarcoma, and breast cancer. The company's preclinical programs include LOXO-195, a drug candidate in preclinical development to address predicted acquired resistance mechanisms; RET inhibitor that optimizes potency for rearranged during transfection (RET) fusion proteins, mutations, and anticipated mechanisms of acquired resistance; and FGFR inhibitor that enables potently inhibiting FGFR isoforms comprising four isoforms with tyrosine kinase domains. It has a drug discovery collaboration agreement with Array BioPharma, Inc. to obtain various rights to TRK inhibitor program and oncology targets. Loxo Oncology, Inc. was founded in 2013 and is headquartered in Stamford, Connecticut.