UMass Chan Medical School Faculty Publications


Evaluating the Role of Macrocycles in the Susceptibility of Hepatitis C Virus NS3/4A Protease Inhibitors to Drug Resistance

UMMS Affiliation

Department of Biochemistry and Molecular Pharmacology

Publication Date


Document Type



Hepacivirus; Protease Inhibitors; Viral Nonstructural Proteins; Drug Resistance, Viral


Bacterial Infections and Mycoses | Biological Phenomena, Cell Phenomena, and Immunity | Digestive System Diseases | Immunology and Infectious Disease | Medical Pharmacology | Microbiology | Pharmaceutical Preparations | Therapeutics | Virus Diseases


The hepatitis C virus (HCV) infects an estimated 150 million people worldwide and is the major cause of viral hepatitis, cirrhosis, and liver cancer. The available antiviral therapies, which include PEGylated interferon, ribavirin, and one of the HCV NS3/4A protease inhibitors telaprevir or boceprevir, are ineffective for some patients and cause severe side effects. More potent NS3/4A protease inhibitors are in clinical development, but the long-term effectiveness of these drugs is challenged by the development of drug resistance. Here, we investigated the role of macrocycles in the susceptibility of NS3/4A protease inhibitors to drug resistance in asunaprevir, danoprevir, vaniprevir, and MK-5172, with similar core structures but varied P2 moieties and macrocyclizations. Linear and macrocyclic analogues of these drugs were designed, synthesized, and tested against wild-type and drug-resistant variants R155K, V36M/R155K, A156T, and D168A in enzymatic and antiviral assays. Macrocyclic inhibitors were generally more potent, but the location of the macrocycle was critical for retaining activity against drug-resistant variants: the P1-P3 macrocyclic inhibitors were less susceptible to drug resistance than the linear and P2-P4 macrocyclic analogues. In addition, the heterocyclic moiety at P2 largely determined the inhibitor resistance profile, susceptibility to drug resistance, and the extent of modulation by the helicase domain. Our findings suggest that to design robust inhibitors that retain potency to drug-resistant NS3/4A protease variants, inhibitors should combine P1-P3 macrocycles with flexible P2 moieties that optimally contact with the invariable catalytic triad of this enzyme.


Hepatitis C, HCV NS3/4A inhibitors, drug resistance

DOI of Published Version



Ali A, Aydin C, Gildemeister R, Romano KP, Cao H, Ozen A, Soumana D, Newton A, Petropoulos CJ, Huang W, Schiffer CA. Evaluating the role of macrocycles in the susceptibility of hepatitis C virus NS3/4A protease inhibitors to drug resistance. ACS Chem Biol. 2013 Jul 19;8(7):1469-78. doi: 10.1021/cb400100g. Link to article on publisher's site


Co-author Aysegul Ozen is a student in the Biochemistry & Molecular Pharmacology program in the Graduate School of Biomedical Sciences (GSBS) at UMass Medical School.

Related Resources

Link to Article in PubMed

Journal/Book/Conference Title

ACS chemical biology

PubMed ID