We presented pre-clinical data on ALN-AAT, an investigational RNAi therapeutic targeting alpha-1 antitrypsin (AAT) for the treatment of AAT deficiency-associated liver disease. New data, presented at the Digestive Disease Week (DDW) meeting, held May 16 – 19, 2015, showed a robust knockdown of serum AAT of up to 93% in non-human primates (NHPs) with monthly subcutaneous dosing. This level of knockdown was highly durable, lasting for greater than 30 days following the final dose. Further, ALN-AAT was found to have a wide therapeutic index based on results from GLP toxicology studies. In addition, study results were reported from a transgenic mouse model of alpha-1 liver disease, where mice overexpress the human Z-AAT protein.