Arrowhead Pharmaceuticals Receives FDA Breakthrough Therapy Designation for Plozasiran in Severe Hypertriglyceridemia
核心洞察
The FDA has granted Breakthrough Therapy designation to Arrowhead's investigational plozasiran for treating severe hypertriglyceridemia (搜索) in adults with triglyceride levels ≥500 mg/dL.
Plozasiran is a first-in-class RNA interference therapeutic targeting apolipoprotein C-III (搜索) to reduce triglyceride levels and is already approved as REDEMPLO (搜索) for familial chylomicronemia syndrome (搜索).
Arrowhead plans to complete three Phase 3 studies by mid-2026 and submit a supplemental New Drug Application by year-end 2026 for this expanded indication.
Arrowhead Pharmaceuticals announced that the U.S. Food and Drug Administration has granted Breakthrough Therapy designation to investigational plozasiran as an adjunct to diet for reducing triglyceride levels in adults with severe hypertriglyceridemia (搜索) (SHTG), defined as triglyceride levels greater than or equal to 500 mg/dL. The designation recognizes the significant unmet medical need for the millions of people globally living with SHTG, who currently have limited and inadequate treatment options.
Breakthrough Therapy Designation Significance
Breakthrough Therapy designation is designed to expedite the development and review of drugs intended to treat serious conditions where preliminary clinical evidence indicates substantial improvement over available therapies on clinically significant endpoints. This regulatory pathway reflects the FDA's recognition of plozasiran's potential to address a critical gap in SHTG treatment.
Understanding Severe Hypertriglyceridemia
Severe hypertriglyceridemia (搜索) is characterized by triglyceride levels exceeding 500 mg/dL, with the most severe form being familial chylomicronemia syndrome (搜索) (FCS) where triglycerides typically exceed 880 mg/dL. SHTG significantly increases the risk of acute pancreatitis (搜索), which often includes recurrent attacks requiring repeat hospital admissions and worsening outcomes. The risk of acute pancreatitis is proportional to the number, characteristics, and concentration of triglyceride-rich lipoproteins, particularly chylomicrons, and increases as triglyceride levels rise.
Plozasiran's Mechanism of Action
Plozasiran represents a first-in-class investigational RNA interference therapeutic designed to reduce production of apolipoprotein C-III (搜索) (apoC-III), a key component of triglyceride-rich lipoproteins and a crucial regulator of triglyceride metabolism. ApoC-III increases triglyceride levels in the blood by inhibiting breakdown of triglyceride-rich lipoproteins by lipoprotein lipase (搜索) and uptake of triglyceride-rich lipoprotein remnants by hepatic receptors in the liver. By reducing apoC-III levels, plozasiran aims to decrease triglycerides and restore lipids to more normal levels.
Phase 3 Clinical Development Program
Arrowhead is conducting three Phase 3 studies evaluating plozasiran in severe hypertriglyceridemia (搜索). The SHASTA-3 and SHASTA-4 studies are double-blind, placebo-controlled trials evaluating plozasiran's efficacy and safety in adults with severe hypertriglyceridemia. Between the two studies, approximately 750 participants were randomized to receive four doses of 25 mg plozasiran or placebo, administered once every three months. The primary endpoint is percent change in fasting serum triglyceride levels from baseline to month 12 compared to placebo.
The MUIR-3 study is a double-blind, placebo-controlled Phase 3 trial evaluating plozasiran in adults with hypertriglyceridemia (triglyceride levels greater than 150 mg/dL and less than 500 mg/dL). Approximately 1,450 participants were randomized to receive four doses of 25 mg plozasiran or placebo once every three months, with the same primary endpoint of percent change in fasting serum triglyceride levels.
Regulatory Timeline and Market Access
Arrowhead is on schedule to complete the SHASTA-3, SHASTA-4, and MUIR-3 Phase 3 clinical studies by mid-2026 and intends to submit a supplemental New Drug Application to the FDA by year-end 2026. The company also plans to seek regulatory approval with additional global regulatory authorities thereafter.
Existing Market Approval
Plozasiran is already approved in the U.S. as REDEMPLO (搜索) as an adjunct to diet to reduce triglycerides in adults with Familial Chylomicronemia Syndrome (搜索), with additional global regulatory submissions and reviews in process. REDEMPLO is the first and only FDA-approved treatment studied in both genetically confirmed and clinically diagnosed patients living with FCS.
The most common adverse reactions in REDEMPLO (搜索)-treated patients include hyperglycemia, headache, nausea, and injection site reaction, occurring in at least 10% of patients treated with REDEMPLO and more than 5% more frequently than with placebo.