ARC-520: Ph IIb hold

Arrowhead said FDA placed a clinical hold on the double-blind, placebo-controlled, U.S. Phase IIb Heparc-2004 trial of IV ARC-520. Arrowhead said FDA placed the hold after deaths occurred in a non-human primate toxicology study in which high doses were given of the company’s EX1 liver-targeted, IV delivery vehicle, which is used in the ARC-520 program. FDA did not say the hold was based on human findings, according to Arrowhead. The company said it believes the primate toxicology study findings are dose level-related and that EX1's safety profile in humans “supports continuing all ongoing clinical studies.” Heparc-2004 is evaluating ARC-520 every 4 weeks for up to 3 doses in combination with entecavir or Viread tenofovir in up to 12 hepatitis B e antigen (HBeAg)-positive patients with chronic HBV infection...