Additional Relevant Details The U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation to LOXO-101, a selective inhibitor of tropomyosin receptor kinase (TRK), “for the treatment of unresectable or metastatic solid tumors with NTRK-fusion proteins in adult and pediatric patients who require systemic therapy and who have either progressed following prior treatment or who have no acceptable alternative treatments.”