TTR and Acute hepatic porphyria: Two kinds of siRNA drugs are currently on the market, Onpattro (patisiran) (33) and Givlaari (givosiran) (34), both encapsulated in liposomes, the former targeting transthyretin (TTR) as an injectable treatment for hereditary transforming amyloidosis (hATTR) (35), and the latter targeting a neurotoxic intermediate (ALAS1) for the treatment of acute hepatic porphyria (36).