Cyclophilins are a family of peptidyl-prolyl isomerases that are implicated in a wide range of diseases including hepatitis C. Our aim was to discover through total synthesis an orally bioavailable, non-immunosuppressive cyclophilin (Cyp) inhibitor with potent anti-hepatitis C virus (HCV) activity that could serve as part of an all oral antiviral combination therapy. An initial lead 2 derived from the sanglifehrin A macrocycle was optimized using structure based design to produce a potent and orally bioavailable inhibitor 3. The macrocycle ring size was reduced by one atom, and an internal hydrogen bond drove improved permeability and drug-like properties. 3 demonstrates potent Cyp inhibition ( Kd = 5 nM), potent anti-HCV 2a activity (EC50 = 98 nM), and high oral bioavailability in rat (100%) and dog (55%). The synthetic accessibility and properties of 3 support its potential as an anti-HCV agent and for interrogating the role of Cyp inhibition in a variety of diseases.
Cyclophilins/antagonists & inhibitors , Drug Design , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/pharmacokinetics , Administration, Oral , Antiviral Agents/administration & dosage , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , Antiviral Agents/pharmacology , Biological Availability , Cell Line , Cyclophilins/chemistry , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/chemistry , Hepacivirus/drug effects , Lactones/administration & dosage , Lactones/chemistry , Lactones/pharmacokinetics , Lactones/pharmacology , Models, Molecular , Protein Conformation , Spiro Compounds/administration & dosage , Spiro Compounds/chemistry , Spiro Compounds/pharmacokinetics , Spiro Compounds/pharmacology
