TTR and polyneuropathy: The therapeutic potential of RNAi is further evidenced by the fact that six siRNA-based drugs have been already approved for clinical use (Patisiran, approved for primary hyperoxaluria; Givosiran, for hereditary transthyretin-mediated amyloidosis (hATTR) with polyneuropathy and for acute hepatic porphyria; Inclisiran for hypercholesterolemia; Lumasiran for primary hyperoxaluria type 1; Vutrisiran for hATTR with polyneuropathy; and Nedosiran for primary hyperoxaluria).