Arrowhead Pharmaceuticals, Inc. (NASDAQ: ARWR) today announced that the United States Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to investigational plozasiran as an adjunct to diet to reduce triglyceride (TG) levels in adults with severe hypertriglyceridemia (SHTG) (TG levels greater than or equal to 500 mg/dL). There are currently limited and inadequate treatment options for the millions of people globally living with SHTG.

Breakthrough Therapy designation is a process designed to expedite the development and review of drugs that are intended to treat a serious condition and where preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over available therapies on clinically significant endpoints1.

Arrowhead is on schedule to complete the SHASTA-3, SHASTA-4, and MUIR-3 Phase 3 clinical studies of plozasiran in mid-2026 and intends to submit a supplemental New Drug Application (sNDA) to the FDA by year-end 2026. Arrowhead also plans to seek regulatory approval with additional global regulatory authorities thereafter.

Severe hypertriglyceridemia (SHTG) is characterized by triglyceride (TG) levels greater than 500 mg/dL, with the most severe form being familial chylomicronemia syndrome (FCS) where TGs typically exceed 880 mg/dL. SHTG significantly increases the risk of acute pancreatitis (AP), which can often include recurrent attacks requiring repeat hospital admissions and worsening outcomes. AP risk is proportional to the number, characteristics, and concentration of triglyceride rich lipoproteins (TRLs), particularly chylomicrons, and increases as TGs rise. Limited treatment options exist to sustainably reduce TGs below guideline directed risk thresholds.

SHASTA-3 (NCT06347003) and SHASTA-4 (NCT06347016) are double-blind, placebo-controlled, Phase 3 studies to evaluate the efficacy and safety of plozasiran in adults with severe hypertriglyceridemia. Between the two studies, approximately 750 participants were randomized to receive 4 doses (once every 3 months) of 25 mg plozasiran or placebo. The primary endpoint is percent change in fasting serum triglyceride levels from baseline to month 12 compared to placebo. After month 12, eligible participants will be offered an opportunity to continue in an optional open-label extension.

MUIR-3 (NCT06347133) is a double-blind, placebo-controlled, Phase 3 study to evaluate the efficacy and safety of plozasiran in adults with hypertriglyceridemia (TGs greater than 150 mg/dL and less than 500 mg/dL). Approximately 1450 participants were randomized to receive 4 doses (once every 3 months) of 25 mg plozasiran or placebo. The primary endpoint is percent change in fasting serum triglyceride levels from baseline to month 12 compared to placebo.

Source: businesswire.com