Alnylam Pharmaceuticals Inc., of Cambridge, Mass., and The Medicines Co. (MDCO), of Parsippany, N.J., filed a clinical trial application with the U.K. Medicines and Healthcare Products Regulatory Agency to initiate a phase I trial with ALN-PCSsc to treat hypercholesterolemia. The subcutaneously administered RNAi therapeutic uses Alnylam's enhanced stabilization chemistry (ESC)-GalNAc-siRNA conjugate delivery platform and targets the gene proprotein convertase subtilisin/kexin type 9, or PCSK9, which affects the metabolism of low-density lipoprotein cholesterol (LDL-C).