The Medicines Company announced that it has initiated study sites and begun enrolling patients in the ORION-1 Phase 2 study to compare the effect of different doses of ALN-PCSsc given as subcutaneous injections in a quarterly or bi-annual dosing regimen in subjects with atherosclerotic cardiovascular disease (ASCVD) or risk equivalent ASCVD and elevated LDL-C. ALN-PCSsc is an investigational RNA interference (RNAi) therapeutic targeting PCSK9 – a genetically validated protein regulator of LDL receptor metabolism. In contrast to anti-PCSK9 monoclonal antibodies (MAbs) that bind to PCSK9 in blood, ALN-PCSsc is a first-in-class investigational medicine that acts by turning off PCSK9 synthesis in the liver. The ORION-1 study is a Phase 2, placebo-controlled, double-blind, randomized trial in 480 subjects with atherosclerotic cardiovascular disease or ASCVD-risk equivalents (e.g., diabetes and familial hypercholesterolemia) and elevated LDL-C despite maximum tolerated doses of LDL-C lowering therapies to evaluate the efficacy, safety, and tolerability of ALN-PCSsc injection(s).