Charles M Rice) were maintained in exponential growth in Dulbecco's modified Eagle's medium supplemented with 10% (v/v) heat-inactivated fetal bovine serum, and 500 µg/ml of G418 (Geneticin, GIBCO/Invitrogen). Subgenomic HCV replicon RNA-containing Huh7 cell line (Clone B cells, kindly provided by Dr. IFN-a, Intron A (Interferon alfa-2b, recombinant) - Schering CorporationĬell culture antiviral assay (HCV Replicon System): To evaluate the in vitro anti-HCV activity of interferon alpha 2b (IFN-a) combined with either beta-D-2'-C-methylcytidine or beta-D-2'-deoxy-2'-fluoro-2'-C-methylcytidine. The global magnitude of hepatitis C virus (HCV) infection has prompted researchers to evaluate a numerous strategies to eradicating the virus. Parts of this work were recently corroborated in a Phase 2b human studies (AASLD 2005, abstract #93) where a prodrug of 2'-MeC (NM-283) combined with peg-interferon produced profound synergistic effects.
No cytotoxic effects were observed with any of the combinations when tested at the highest concentrations.Ĭonclusion: Using a robust methodology for determining drug interactions, both anti-HCV nucleosides analogs studied demonstrated synergistic anti-HCV activity when combined with IFN-alpha 2b in the replicon system without any cytotoxicity. Notably, for combinations of IFN-a with either 2'-MeC or 2'-F-MeC, the average CI at 90% inhibition at all ratios tested was 0.31 and 0.47, respectively. For the combination of 2'-F-MeC with IFN-a at ratios of 1:10, 1:5, 1:1.5, and 1:1, the CIwt were 0.78, 0.70, 0.42, and 0.38, respectively, indicating also synergistic activity. Results: The combination of 2'-MeC with IFN-a at ratios of 2:1, 1:2, and 1:3 had weighted an average combination index (CIwt) of 0.45, 0.51, and 0.33, respectively indicating synergistic antiviral effects since CI 1 indicate synergism, additive effect, and antagonism, respectively. Data analyses were performed using CalcuSyn program. After incubation for 5 days, total cellular RNA was extracted and both ribosomal RNA and HCV replicon RNA were amplified in a single step multiplex real-time PCR assay. Methods: Huh-7 cells containing the self-replicating subgenomic HCV replicon (Clone B) were used for drug combination studies.
In this study, we evaluated the in vitro anti-HCV activity of interferon alpha-2b (IFN-a, Schering Corporation) combined with two nucleosides analogs: beta-D-2'-C-methylcytidine (2'-MeC NM-107 ) and beta-D-2'-deoxy-2'-fluoro-2'-C-methylcytidine (2'-F-MeC PSI-6130). The use of new nucleoside analogs, in combination with interferon, to treat HCV infections that sustain viral suppression with reduced side effects is needed. Dieterich D et al., J Hepatol 44, Suppl.2: S-271-272, 2006īackground and aims: Treatment of hepatitis C virus (HCV) infection with interferon-ribavirin combination therapies results in low rates of sustained virological response and a wide variety of side effects. Parts of this work were recently corroborated in a Phase 2b human studies (O'Brien et al., 2005 Dieterich et al., 2006) where a prodrug of 2'-MeC (NM-283) combined with peg-interferon produced profound synergistic effects. Two potentially useful anti-HCV nucleosides (NM283, PSI-6130, both HCV polymerase inhibitors) were assessed in a cell based replicon system for future use as combined modality therapy agents with interferon.īoth anti-HCV nucleoside analogs demonstrated at high effect levels strong synergistic interactions when combined with IFN-alpha 2b in the replicon system without apparent cytotoxicity. "COMBINATIONS OF 2'-METHYLCYTIDINE ANALOGS WITH INTERFERON ALPHA-2B LEAD TO SYNERGISTIC INHIBITION OF HEPATITIS C VIRUS REPLICATION IN A REPLICON SYSTEM"Įmory University School of Medicine & Veterans Affairs Medical Center, Decatur, Georgia, USA PegIntron + 2 HCV Nucleosides Show SynergyĤ2nd Meeting of the European Association for the Study of Liver Diseases
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