Sydney, Australia-based Benitec (NASDAQ:BNTC) announces that its DNA-directed RNA interference (ddRNAi) candidate, BB-HB-331, showed robust and durable hepatitis B virus (HBV) suppression in vivo following a single administration.
The HBV suppression activity of BB-HB-331 was assessed in the Phoenix mouse model in which murine liver cells were replaced by human hepatocytes which made them susceptible to HBV infection. Once infected, the mice received a single systemic injection of BB-HB-331. Serum antigen levels, HBV viral proteins and extracellular HBV DNA were measured once per week for the duration of the eight-week study.
Results showed a 1.83 log knockdown of serum HBV DNA, equivalent to a 98.5% reduction of circulating HBV. In addition, intracellular HBV DNA was reduced 94.9% while HBV surface antigen (HBsAg) and e antigen (HBeAg) were reduced by 97.6% and 92.6%, respectively. The results validated the previously reported in vitro findings.
BB-HB-331 combines the gene silencing of RNA interference with the therapeutic potential of gene therapy. It is comprised of an AAV8 capsid (protein shell of a virus) and recombinant DNA engineered to express three short hairpin RNAs that target and inhibit viral RNA expressed from three regions across multiple HBV genotypes. The company plans to advance BB-HB-331 to clinical development.
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