Arrowhead Pharmaceuticals Secures TGA Approval for REDEMPLO® (plozasiran) in Australia, Broadening Access for Patients with Familial Chylomicronemia Syndrome (FCS)
Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) has announced a significant regulatory milestone with the approval of REDEMPLO by Australia’s Therapeutic Goods Administration (TGA). The therapy has been authorized as an adjunct to dietary management for adult patients living with familial chylomicronemia syndrome (FCS), a rare and severe genetic disorder characterized by extremely elevated triglyceride levels and a heightened risk of life-threatening complications.
This approval marks an important advancement for patients in Australia, as REDEMPLO becomes the first and only approved treatment specifically indicated for FCS in the country. The therapy is authorized for use in adults with either genetically confirmed or clinically diagnosed FCS whose triglyceride levels remain inadequately controlled despite standard treatment approaches. The decision further strengthens Arrowhead’s growing global footprint for plozasiran, following prior approvals in the United States, Canada, and China, as well as a positive regulatory opinion in Europe.
Addressing a Rare but Serious Disease
FCS is an ultra-rare metabolic disorder that affects an estimated 1 to 13 individuals per million worldwide. Despite its rarity, the condition carries a substantial clinical burden. Patients with FCS experience extremely elevated triglyceride levels—often many times higher than normal—which can lead to recurrent episodes of acute pancreatitis. These episodes are not only painful and debilitating but can also be life-threatening, particularly when they occur repeatedly over time.
One of the major challenges associated with FCS is that it is frequently underdiagnosed or misdiagnosed, due in part to its rarity and overlap with other lipid disorders. Even when diagnosed, treatment options have historically been limited, with many patients relying on strict dietary restrictions and conventional lipid-lowering therapies that often fail to adequately control triglyceride levels.
The approval of REDEMPLO in Australia therefore represents a meaningful step forward in addressing this unmet medical need, offering a targeted therapeutic option that directly addresses the underlying biology of the disease.
Mechanism of Action: Targeting ApoC-III via RNA Interference
REDEMPLO is based on Arrowhead’s proprietary Targeted RNAi Molecule (TRiM™) platform, which leverages RNA interference (RNAi) technology to selectively silence disease-causing genes. Specifically, plozasiran targets the messenger RNA responsible for producing apolipoprotein C-III (apoC-III), a protein that plays a central role in regulating triglyceride metabolism.
ApoC-III acts as an inhibitor of triglyceride breakdown and clearance in the bloodstream. Elevated levels of this protein are associated with increased triglyceride concentrations, contributing to the pathophysiology of FCS. By reducing the production of apoC-III, REDEMPLO enhances the body’s ability to clear triglycerides, thereby lowering their levels in circulation.
This mechanism is supported by genetic evidence showing that individuals with naturally occurring loss-of-function mutations in the APOC3 gene tend to have significantly lower triglyceride levels and a reduced risk of cardiovascular disease. By mimicking this effect through RNAi, plozasiran offers a highly targeted and potentially transformative approach to managing FCS.
Clinical Evidence from the PALISADE Study
The TGA’s approval of REDEMPLO was supported by robust clinical data from the Phase 3 PALISADE trial, a randomized, double-blind, placebo-controlled study involving adults with either genetically confirmed or clinically diagnosed FCS. The trial was conducted across 39 global sites, including five locations in Australia, reflecting a diverse and representative patient population.
PALISADE successfully met its primary endpoint, demonstrating a statistically significant reduction in triglyceride levels among patients treated with REDEMPLO compared to placebo. Patients receiving the 25 mg dose of plozasiran experienced a median reduction in triglycerides of 80% from baseline, compared to a 17% reduction observed in the placebo group. This level of reduction is considered clinically meaningful and represents a substantial improvement over existing treatment options.
In addition to lowering triglyceride levels, the study also demonstrated significant reductions in apoC-III levels, further validating the drug’s mechanism of action. Importantly, REDEMPLO treatment was associated with a marked decrease in the incidence of acute pancreatitis events—a key clinical outcome for patients with FCS.
In the pooled analysis of treatment groups receiving 25 mg and 50 mg doses, the odds of experiencing acute pancreatitis were reduced by 83% compared to placebo. Specifically, only two events were reported among patients receiving plozasiran, compared to seven events in the placebo group. These findings highlight the potential of REDEMPLO not only to improve biochemical markers but also to reduce serious clinical complications.
Safety and Administration
REDEMPLO is administered as a subcutaneous injection once every three months, offering a convenient dosing schedule that may improve adherence compared to more frequent treatments. The safety profile observed in clinical trials was generally consistent with expectations for this class of therapy.
According to the Australian Product Information, the most commonly reported adverse reaction was hyperglycaemia, occurring in approximately 12.8% of patients. Other common side effects included headache (6.8%), nausea (4.7%), and injection site reactions (4.7%). These adverse events were generally manageable and did not outweigh the overall clinical benefits observed in the study.
Expert Perspectives on Clinical Impact
Clinical experts have emphasized the significance of this approval for patients living with FCS. Gerald F. Watts, a leading authority in cardio-metabolic medicine at the University of Western Australia, highlighted the substantial burden faced by patients with this condition, including the lifelong risk of recurrent pancreatitis and limited treatment options.
He noted that the PALISADE study demonstrated both substantial and sustained reductions in triglyceride levels, underscoring the therapeutic potential of RNA interference approaches in conditions that have historically been difficult to treat. According to Watts, plozasiran represents a major advancement in the management of FCS and a critical step toward expanding treatment options for this underserved patient population.
Global Regulatory Progress and Recognition
The approval of REDEMPLO in Australia adds to a growing list of regulatory achievements for the therapy. In addition to approvals in multiple countries, plozasiran has received several important regulatory designations aimed at expediting its development and review.
In the United States, the U.S. Food and Drug Administration granted Breakthrough Therapy Designation, Fast Track Designation, and Orphan Drug Designation for plozasiran in FCS. Similarly, the European Medicines Agency has granted Orphan Medicinal Product Designation, recognizing the therapy’s potential to address a rare disease with high unmet need.
These designations reflect the strength of the clinical data and the urgent need for effective treatments in FCS, facilitating faster regulatory pathways and broader patient access.
Scientific Dissemination and Recognition
The findings from the PALISADE study have been widely disseminated within the scientific and medical communities. Data from the trial were presented at major international conferences, including the European Society of Cardiology Congress 2024 and the American Heart Association Scientific Sessions 2024.
In addition, the results were published in leading peer-reviewed journals such as The New England Journal of Medicine and Circulation, further validating the scientific rigor and clinical relevance of the data.
Expanding Access and Future Outlook
Arrowhead’s leadership has emphasized its commitment to expanding access to REDEMPLO for patients worldwide. According to CEO Christopher Anzalone, the approval in Australia underscores the potential of the company’s TRiM™ platform to develop targeted RNAi therapies across a range of diseases and tissues.
The company continues to work with regulatory authorities globally to bring plozasiran to additional markets, with the goal of ensuring that patients with FCS have access to effective and innovative treatment options.
Looking ahead, the success of REDEMPLO may also pave the way for further applications of RNA interference technology in metabolic and cardiovascular diseases. By demonstrating the ability to safely and effectively target specific molecular pathways, therapies like plozasiran could open new avenues for precision medicine in conditions that have long lacked targeted solutions.
The approval of REDEMPLO by Australia’s Therapeutic Goods Administration represents a major milestone in the treatment of familial chylomicronemia syndrome. With its novel RNAi-based mechanism, strong clinical efficacy, and manageable safety profile, plozasiran offers new hope for patients facing a challenging and potentially life-threatening condition.
As Arrowhead continues to expand its global reach and advance its pipeline, REDEMPLO stands as a compelling example of how innovative science can translate into meaningful clinical benefits, addressing unmet needs and improving outcomes for patients around the world.
About FCS
Familial chylomicronemia syndrome (FCS) is a severe and rare disease leading to extremely high triglyceride (TG) levels, typically over 10 mmol/L (880 mg/dL). Such severe elevations can lead to various serious signs and symptoms including acute and potentially fatal pancreatitis, chronic abdominal pain, diabetes, hepatic steatosis, and cognitive issues. Currently, there are limited therapeutic options to adequately treat FCS.
About the PALISADE Phase 3 Study
The PALISADE study (NCT05089084) was a Phase 3 placebo-controlled study to evaluate the efficacy and safety of plozasiran in adults with genetically confirmed or clinically diagnosed FCS. The primary endpoint of the study was percent change from baseline in fasting TG versus placebo at Month 10. A total of 75 subjects distributed across 39 different sites in 18 countries were randomized to receive 25 mg plozasiran, 50 mg plozasiran, or matching placebo once every three months. Participants who completed the randomized period were eligible to continue in a 2-part extension period, where all participants receive plozasiran.
About REDEMPLO® (plozasiran)
REDEMPLO (plozasiran) is the first and only siRNA treatment approved in these countries that has been studied in both genetically confirmed and clinically diagnosed patients living with FCS. REDEMPLO is a first-in-class siRNA therapeutic designed to suppress the production of apoC-III, a protein produced in the liver that raises triglyceride levels by slowing their breakdown and clearance. By targeting apoC-III with sustained silencing, REDEMPLO delivers significant reductions in triglyceride levels. REDEMPLO is self-administered via subcutaneous injection once every three months.
The EMA CHMP has adopted a positive opinion recommending the European Marketing Authorization of REDEMPLO (plozasiran), which is already approved by the U.S. Food and Drug Administration, Health Canada, and China’s National Medical Products Administration as an adjunct to diet to reduce triglycerides for adults with Familial Chylomicronemia Syndrome (FCS).
Plozasiran is also being investigated in the SHASTA-3 (NCT06347003), SHASTA-4 (NCT06347016), and SHASTA-5 (NCT06880770) Phase 3 studies in adults with severe hypertriglyceridemia and the MUIR-3 (NCT06347133) Phase 3 study in adults with hypertriglyceridemia. In December 2025, plozasiran was granted Breakthrough Therapy designation by the U.S. FDA in severe hypertriglyceridemia.
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.
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