Arbutus Biopharma Presents Preclinical Data at the 2015 International Meeting on Molecular Biology of Hepatitis B Viruses

Arbutus Biopharma Corporation ABUS, an industry-leading therapeutic solutions company focused on developing a cure for chronic hepatitis B virus infection (HBV), today announced three presentations at the 2015 International Meeting on Molecular Biology of Hepatitis B Viruses being held on October 4 – 8, 2015, at Dolce Bad Nauheim, Germany. "We are excited to present these data supporting our HBV research and development efforts, in particular, related to TKM-HBV, our lead HBV RNAi clinical candidate, as well as our novel cccDNA formation inhibitors," said Dr. Michael J. Sofia, Arbutus's Chief Scientific Officer. "Our preclinical results validate that the unique three RNAi trigger design of TKM-HBV leads to reductions in hepatitis B surface antigen (HBsAg) and the other viral antigens but also results in a reduction of cccDNA levels, as well as unique synergistic effects of our novel cccDNA inhibitors in combination with nucleot(s)ide analogs." Presentation Information and Abstract Summaries: 1. "Profiling the Effects of TKM-HBV on cccDNA in Humanized Chimeric Mouse Model of HBV" Summary: Data utilizing quantitative real-time PCR (qPCR) combined with differential tissue lysis to enable specific detection of cccDNA showed that four weekly doses of TKM-HBV alone at 0.3 mg/kg was able to reduce cccDNA levels by 42% when compared to untreated animals. This confirms the unique three-trigger RNAi product designed to reduce all viral antigens also results in reduction of cccDNA levels. Date and Time: October 6, 2015, from 7.00am – 9.00am (PT) /10.00 am – 12.00pm (ET) 2. "TKM-HBV, a Novel RNA Interference Treatment for Chronic Hepatitis B, Mediates Global Viral Antigen Reductions through a Well-Defined Mechanism of Action" Summary: Through a well-characterized mechanism of action, TKM-HBV mediated cleavage of viral RNA transcripts leads to global reduction of all viral antigens from intrahepatic and peripheral compartments within days after a single treatment. In addition to creating a permissive environment for immune response activation by effective suppression of HBsAg, repression of viral proteins such as HBcAg and HBx may also be beneficial through inhibiting cccDNA replication, stability or transcriptional activity. This confirms the unique three-trigger product targets all the HBV mRNA transcripts and leads to reduction of all viral antigens. Date and Time: October 7, 2015, from 8.00am – 10.00am (PT)/ 11.00am – 1.00pm (PT) 3. "Novel Inhibitors of HBV cccDNA Formation Exhibit Synergistic Effects with Nucleoside and Nucleotide Analogs" Summary: Multi-dose combinations of ARB-199 and ARB-596 with nucs were examined for cccDNA expression and found to 1) have no antagonistic effects between the two types of compounds, and 2) result in measurable synergy at suboptimal doses of both nucs and cccDNA formation inhibitor compounds. These results suggest that equivalent clinical combinations could potentially result in faster declines of cccDNA levels than is currently obtainable with 'nuc' therapeutics. Date and Time: October 7, 2015, from 8.00am – 10.00am (PT)/ 11.00am – 1.00pm (PT)