IDX-184 is a superior HCV direct-acting antiviral drug: a QSAR study

Quantitative structure-activity relationship (QSAR) parameters are good indicators for the reactivity of direct-acting antiviral drugs. Since molecular structure is related to molecular function, careful selection of molecular substitutions will result in more drugs that are potent. In this work, QSAR parameters are selected in order to compare the four drugs used as nucleotide inhibitors (NIs) for non-structural 5B (NS5B) RNA-dependent RNA polymerase (RdRp) of hepatitis C virus (HCV). These drugs are: ribavirin (widely used over the last 20 years), sofosbuvir (approved on December 2013 by FDA), and finally IDX-184 and R7128 (phase IIb of clinical trial drugs). The nucleotide analogues uracil (U), guanine (G), and cytosine (C) from which these drugs are fabricated are also compared to that group of drugs. QSAR parameters suggested that the drug IDX-184 is the best among all of the studied NIs. It also shows that NIs are always more reactive than their parent nucleotide.

The active site environment of 12 amino acids coordinated with IDX-184 through two Mg²⁺. The interaction with HCV subtypes 1a, 2b, and 3b is better than 4a subtype.