ARC-520 activity is assessed by measuring percent change of quantitative HBsAg decline from baseline. For patients receiving ARC-520 in cohort 1, mean nadir HBsAg was -39% (range -22 to -57) with a mean change on day 85 of -31% (range -14 to -39). For patients receiving ARC-520 in cohort 2, mean nadir HBsAg was - 51% (range -46 to -59) with a mean change on day 85 of -22% (range -7 to -40). For cohort 2, the percent reduction in HBsAg was statistically significant vs placebo for Days 3 through 43 post dose. This is the first time that a reduction in HBsAg mediated through RNA interference has been shown in chronic HBV patients.There is a formula to convert percent change in quantitative HBsAg decline from baseline into a log reduction. The 51% reduction disclosed in the abstract for the 2 mg/kg dose of ARC-520 equates to a 0.3-log reduction.
Labels: AASLD 2014, ARC-520, results