GS-6620

GS-6620 is an antiviral drug that functions as a nucleotide analogue prodrug, specifically designed to inhibit the hepatitis C virus (HCV). It acts as a pangenotype inhibitor of HCV replication by targeting the nonstructural protein 5B RNA-dependent RNA polymerase (NS5B). The active metabolite of GS-6620, known as GS-441326, competitively inhibits NS5B-catalyzed ATP incorporation and causes chain termination during viral RNA synthesis. This mechanism provides high selectivity for viral polymerase over host enzymes and confers a high barrier to resistance. Despite potent in vitro activity against multiple HCV genotypes and some other viruses, clinical development was hampered by poor and variable oral absorption leading to unpredictable blood levels. The drug was developed primarily for hepatitis C but has also been researched for other viral diseases such as Ebola virus disease[1][3][4][6].