Arrowhead Pharmaceuticals plans to file a supplemental New Drug Application with the U.S. Food and Drug Administration for plozasiran in severe hypertriglyceridemia by the end of 2026, the company said on Monday.
The filing will use a Priority Review Voucher purchased on August 4, 2026. Arrowhead presented results from two Phase 3 studies, SHASTA-3 and SHASTA-4, during a session at the European Society of Cardiology Congress 2026 in Munich. The trials enrolled 757 patients who received either plozasiran 25 mg or a placebo subcutaneously once every three months.
Both studies met their primary and secondary endpoints. At Month 12, plozasiran reduced triglycerides by 79% in SHASTA-3 and 81% in SHASTA-4 compared with placebo. More than 90% of plozasiran-treated patients in both studies achieved triglyceride levels below 500 mg/dL, versus approximately 50% in the placebo group. Over half of plozasiran-treated patients reached levels below 150 mg/dL.
In a pooled analysis, plozasiran reduced acute pancreatitis events by 78% versus placebo. Among patients with triglycerides at or above 500 mg/dL and a prior history of acute pancreatitis, the treatment reduced event rates by 91%.
Treatment-emergent adverse events occurred in 73% of patients in both the plozasiran and placebo groups. Serious adverse events were reported in 8.3% of plozasiran patients and 10% of placebo patients. The most common adverse events in the plozasiran group included worsening glycemic control at 14.3% and diarrhea at 5.6%. Three fatal events occurred in plozasiran-treated patients, all attributed to pre-existing conditions and assessed as unrelated to the study treatment.
Plozasiran is currently approved under the brand name REDEMPLO for the treatment of familial chylomicronemia syndrome in the U.S., Canada, China, Australia, and the European Union.
