Arrowhead Pharmaceuticals Acquires FDA Priority Review Voucher to Accelerate Plozasiran Approval for Severe Hypertriglyceridemia
Arrowhead Pharmaceuticals, Inc. has announced that it has entered into an agreement with an undisclosed third party to acquire a U.S. Food and Drug Administration (FDA) Rare Pediatric Disease Priority Review Voucher (PRV), a strategic move aimed at accelerating the regulatory review of its lead RNA interference (RNAi) therapy, plozasiran. The company intends to apply the voucher to an upcoming Supplemental New Drug Application (sNDA) seeking to expand the approved use of plozasiran to include patients with severe hypertriglyceridemia (sHTG).
The sNDA submission is expected before the end of 2026. If accepted with the Priority Review Voucher, the FDA’s review period would be shortened from the standard 10 months to approximately six months, potentially allowing eligible patients to gain earlier access to a new treatment option for a serious lipid disorder associated with life-threatening complications.
The acquisition reflects Arrowhead’s continued commitment to accelerating the development and commercialization of innovative RNAi therapies while addressing significant unmet medical needs in cardiovascular and metabolic diseases.
Strategic Use of a Rare Pediatric Disease Priority Review Voucher
Priority Review Vouchers are valuable regulatory assets awarded by the FDA to companies that successfully develop treatments for qualifying rare pediatric diseases. Once issued, these vouchers may either be used by the original recipient or sold to another pharmaceutical company.
When redeemed, a Priority Review Voucher shortens the FDA’s target review timeline for a qualifying drug application from the standard ten months to six months. Although the voucher does not alter the agency’s scientific review standards or approval requirements, it can significantly accelerate the availability of new therapies by reducing regulatory review time.
For companies developing medicines addressing serious diseases with high unmet medical need, earlier approval can provide important clinical and commercial advantages.
Arrowhead’s decision to acquire a voucher rather than wait for standard review demonstrates the company’s confidence in the clinical profile of plozasiran and its desire to bring the therapy to patients as quickly as possible.
Expanding Plozasiran’s Clinical Use
Arrowhead plans to apply the Priority Review Voucher to its Supplemental New Drug Application for plozasiran, seeking to broaden the medicine’s approved indication beyond its current use.
The company intends to expand treatment eligibility to include patients diagnosed with severe hypertriglyceridemia, a disorder characterized by extremely elevated blood triglyceride levels that significantly increase the risk of acute pancreatitis.
The supplemental regulatory filing is expected to be submitted before the conclusion of 2026.
If approved, the expanded indication would allow a much larger patient population to benefit from plozasiran’s triglyceride-lowering capabilities.
Understanding Severe Hypertriglyceridemia
Triglycerides are a type of fat found in the bloodstream that serve as an important source of energy for the body. However, excessively high triglyceride concentrations can become medically dangerous.
Severe hypertriglyceridemia generally refers to triglyceride levels that rise far above normal physiological ranges. Patients with the condition often experience persistent elevations despite lifestyle modifications, including dietary changes and conventional lipid-lowering medications.
One of the most serious consequences of severe hypertriglyceridemia is acute pancreatitis, an inflammatory condition affecting the pancreas that can cause severe abdominal pain, digestive dysfunction, organ failure, repeated hospitalization, and, in some cases, death.
Each episode of pancreatitis carries the risk of long-term pancreatic damage and additional complications, making effective triglyceride reduction an important therapeutic goal.
Although existing treatment options can lower triglyceride levels in some patients, many individuals with severe disease continue to face elevated risks despite available therapies.
Consequently, there remains substantial interest in developing more effective targeted treatments capable of providing durable triglyceride control.
Positive Phase 3 Results Strengthen Confidence
Arrowhead’s decision to accelerate regulatory review follows encouraging topline data from its recently completed global Phase 3 SHASTA-3 and SHASTA-4 clinical studies evaluating plozasiran in patients with severe hypertriglyceridemia.
According to the company, the positive results from these pivotal studies have reinforced confidence in the therapy’s potential to address an important unmet medical need.
Although complete clinical data have yet to be fully presented, Arrowhead indicated that the findings support the company’s plans to pursue regulatory approval for the expanded indication.
The Phase 3 program represents a significant milestone in plozasiran’s clinical development, providing evidence necessary to support regulatory review and potential commercialization for a broader patient population.
Leadership Highlights the Importance of Faster Access
Christopher Anzalone, Ph.D., President and Chief Executive Officer of Arrowhead Pharmaceuticals, emphasized that recent clinical progress has strengthened the company’s belief in plozasiran’s therapeutic potential.
He stated that the encouraging results from the SHASTA-3 and SHASTA-4 studies increased confidence that plozasiran could meaningfully transform treatment for patients living with severe hypertriglyceridemia.
According to Anzalone, acquiring the Priority Review Voucher represents an important step toward accelerating patient access to the therapy by reducing the regulatory review timeline.
Earlier availability could provide physicians with an additional treatment option sooner while benefiting patients who remain at significant risk for acute pancreatitis.
Building on Existing Regulatory Success
Plozasiran has already established an international regulatory presence through approvals in several major healthcare markets.
The therapy is currently marketed under the brand name REDEMPLO® and has received regulatory approval in the United States, the European Union, China, Australia, and Canada.
Its current approved indication is as an adjunct to dietary management for reducing triglyceride levels in adults with genetically confirmed or clinically diagnosed familial chylomicronemia syndrome (FCS).
These approvals represent important validation of the medicine’s clinical effectiveness and safety profile.
Arrowhead now seeks to build upon this regulatory foundation by expanding access beyond FCS patients to include individuals diagnosed with severe hypertriglyceridemia who may similarly benefit from targeted triglyceride reduction.
Familial Chylomicronemia Syndrome: A Rare but Serious Disorder
Familial chylomicronemia syndrome is considered the most severe form of hypertriglyceridemia.
The rare inherited disorder results from genetic abnormalities that impair the body’s ability to metabolize triglyceride-rich lipoproteins, leading to extremely elevated triglyceride concentrations.
Patients with FCS frequently experience recurrent episodes of acute pancreatitis beginning early in life and often require strict dietary fat restrictions in addition to specialized medical treatment.
Because conventional lipid-lowering therapies frequently provide limited benefit, targeted therapies such as plozasiran have emerged as important treatment options for this patient population.
The successful approval of REDEMPLO for FCS established Arrowhead’s expertise in developing RNA interference therapies targeting disorders of triglyceride metabolism.
RNA Interference: A Precision Therapeutic Approach
Plozasiran is based on Arrowhead’s RNA interference (RNAi) technology platform, which utilizes naturally occurring biological mechanisms to selectively silence disease-causing genes.
Rather than treating disease symptoms alone, RNAi therapies reduce production of proteins that contribute directly to disease processes.
This targeted approach has attracted increasing attention across numerous therapeutic areas, including cardiovascular disease, metabolic disorders, liver disease, and rare genetic conditions.
RNAi medicines offer the potential for prolonged therapeutic effects following relatively infrequent dosing, making them attractive alternatives to conventional chronic therapies.
Arrowhead has developed an extensive pipeline utilizing this technology, with programs spanning multiple disease areas beyond lipid disorders.
Importance of Priority Review
While the acquisition of a Priority Review Voucher does not guarantee FDA approval, it offers important advantages once a regulatory application is accepted for review.
Shortening the review timeline by approximately four months can have meaningful implications for patients awaiting new therapies, particularly in diseases associated with serious complications or limited treatment options.
For healthcare providers, earlier approval expands therapeutic choices sooner.
For patients, earlier access may reduce disease burden and potentially prevent serious clinical events.
For pharmaceutical companies, accelerated review can also allow earlier commercialization while supporting continued investment in future research and development.
Transaction Remains Subject to Regulatory Conditions
Arrowhead noted that completion of the voucher acquisition remains subject to several customary closing requirements.
These include expiration or termination of the waiting period required under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as well as satisfaction of additional standard closing conditions associated with the transaction.
Upon completion, the company intends to reserve the voucher specifically for the planned plozasiran supplemental regulatory submission.
The acquisition of a Rare Pediatric Disease Priority Review Voucher underscores Arrowhead Pharmaceuticals’ strategic focus on accelerating innovation and improving patient access to advanced RNAi therapies. By shortening the FDA review timeline for plozasiran’s planned supplemental application, the company aims to make a promising treatment available sooner for individuals living with severe hypertriglyceridemia, a condition associated with a high risk of acute pancreatitis and significant unmet medical need.
Combined with encouraging Phase 3 SHASTA-3 and SHASTA-4 clinical data and the medicine’s existing international approvals for familial chylomicronemia syndrome, the regulatory strategy positions plozasiran for potential expansion into a much broader patient population. As Arrowhead prepares its supplemental application before the end of 2026, the company continues advancing its broader mission of developing innovative RNA interference medicines capable of addressing serious genetic and metabolic diseases through precise, targeted therapies.
About Severe Hypertriglyceridemia
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. Elevated TGs can also increase the risk of atherosclerotic cardiovascular disease (ASCVD). Limited treatment options exist to sustainably reduce TGs below guideline directed risk thresholds.
About REDEMPLO® (plozasiran)
REDEMPLO (plozasiran) is currently approved by the U.S. Food and Drug Administration, Health Canada, China’s National Medical Products Administration, the Australian Therapeutic Goods Administration, and by the European Commission as an adjunct to diet to reduce triglycerides for adults with FCS. REDEMPLO is the first and only siRNA treatment approved in these countries to be studied in both clinically diagnosed and genetically confirmed patients living with FCS.
REDEMPLO is designed to suppress the production of apolipoprotein C-III (APOC3), a protein produced in the liver that raises triglyceride levels by slowing their breakdown and clearance. By targeting APOC3 with sustained silencing, REDEMPLO delivers significant reductions in triglyceride levels. REDEMPLO is self-administered via subcutaneous injection once every three months.
REDEMPLO has been granted Orphan Medicinal Product Designation by the EMA for the treatment of patients with FCS, and Breakthrough Therapy Designation, Fast Track Designation, and Orphan Drug Designation by the U.S. FDA for the treatment of patients with FCS and was also granted Breakthrough Therapy designation by the U.S. FDA in severe hypertriglyceridemia.
Sanofi acquired the rights to develop and commercialize REDEMPLO in Greater China, with Arrowhead retaining rights to REDEMPLO in all geographies, outside of Greater China.
For more information about REDEMPLO, visit Our Medicines.
About Arrowhead Pharmaceuticals
Arrowhead Pharmaceuticals (NASDAQ: ARWR) is a commercial-stage pharmaceutical company developing medicines that treat intractable diseases by silencing the genes that cause them, harnessing the natural RNA interference (RNAi) mechanism. The company has built a broad portfolio of clinical and commercial RNAi therapeutics through its industry-leading targeted RNAi molecule (TRiM™) platform, which can precisely silence genes in a wide range of cell types, including liver, lung, muscle, adipose, and central nervous system tissue. At Arrowhead, we rapidly advance potential best- and first-in-class RNAi treatments for diseases with significant unmet medical need, because every day matters to the patients we serve.