The agreement between gout player Horizon plc and RNAi expert Arrowhead Pharmaceuticals Inc. could result in a subcutaneously given, infrequently dosed fix for the disease that takes aim at xanthine dehydrogenase. “They brought us the target – it wasn’t something we were developing,” said Arrowhead CEO Christopher Anzalone, but the Pasadena, Calif.-based firm’s research on hepatocyte-directed therapies provides confidence.