Arrowhead Pharmaceuticals (Nasdaq: ARWR) is accelerating the expansion of its APOC3-targeting siRNA therapy Redemplo (plozasiran) into severe hypertriglyceridemia (sHTG) by acquiring a US FDA Rare Pediatric Disease Priority Review Voucher (PRV). The California-based company said it intends to apply the voucher to a planned supplemental New Drug Application (sNDA) for the indication.
The PRV acquisition follows topline Phase III results from the SHASTA-3 and SHASTA-4 studies, reported on July 22, 2026, which Arrowhead said support the planned sNDA submission. Across the two trials, quarterly 25 mg plozasiran reduced triglycerides by approximately 80% versus placebo over 12 months and significantly reduced acute pancreatitis events without new safety signals, according to the company. Full data will be presented at the European Society of Cardiology Congress later this month.
Plozasiran silences hepatic APOC3 gene expression via RNA interference, suppressing APOC3 protein production and thereby reducing inhibition of lipoprotein lipase-mediated clearance of triglyceride-rich lipoproteins.
A PRV reduces the US FDA review timeline for an sNDA from the standard 10 months to six months. Arrowhead said it expects to file the sNDA before the end of 2026 using data from SHASTA-3 and SHASTA-4. Plozasiran was approved in the US for familial chylomicronemia syndrome (FCS) in November 2025 and has since received approvals in the EU, Canada, China, and Australia. The sHTG population is substantially larger than the estimated 6,500 patients with FCS in the US. Arrowhead also received Breakthrough Therapy Designation for plozasiran in sHTG in December 2025.