The FDA approved Arrowhead Pharmaceuticals’ RNAi therapeutic Redemplo (plozasiran) for familial chylomicronemia syndrome (FCS), marking Arrowhead’s entry into the commercial stage and the second RNAi approval for the indication. Approval arrives as Arrowhead set a notably lower list price than incumbent rival Ionis, triggering a pricing skirmish in a small rare-disease market. Redemplo’s clearance positions Arrowhead against Ionis’s existing therapy in FCS; company statements emphasize dosing and safety advantages while payor and competitor dynamics now center on price. Industry sources flagged that Arrowhead’s aggressive pricing is intended to capture rapid uptake in a concentrated patient population but could pressure margins and spur patent and reimbursement disputes. For context, familial chylomicronemia syndrome is an inherited disorder of triglyceride metabolism that causes extreme hypertriglyceridemia and recurrent pancreatitis; RNA interference (RNAi) drugs use small interfering RNAs to reduce target protein synthesis at the mRNA level. The approval signals RNAi’s maturation into a commercial modality and raises questions about price-setting strategies in rare-disease launches.