Alnylam Pharmaceuticals ($ALNY) began a Phase II study of its RNAi drug designed to treat TTR-mediated amyloidosis, an inherited, fatal disease caused by genetic mutations. The company uses a GalNAc-siRNA platform to deliver the RNAi genetic silencers that target the mutated transthyretin (TTR) gene. The drug would be the first genetic treatment for the disease, which affects about 50,000 people worldwide. The subcutaneously delivered ALN-TTRsc is the most advanced GalNAc-conjugate RNAi drug in Alnylam's pipeline and the first to enter Phase II trials. Release