By Padmanabhan Ananthan and Christy Santhosh
(Reuters) -The U.S. Food and Drug Administration approved Arrowhead Pharmaceuticals’ drug for a type of genetic disorder that causes extremely high levels of fat in the bloodstream, the company said on Tuesday.
The approval marks Arrowhead’s first product on the market and the second U.S.-authorized treatment for a hereditary condition known as familial chylomicronemia syndrome.
In a late-stage study with 75 patients, the drug branded as Redemplo reduced triglycerides, a key hallmark of the disease, by 80% and cut the risk of pancreatitis by 83% versus placebo.
FCS is a rare inherited disorder caused by defects in lipoprotein lipase, an enzyme responsible for breaking down fat particles, leading to very high triglyceride levels in the blood.
The disorder causes symptoms such as abdominal pain and, in severe cases, acute pancreatitis. It is estimated to affect 3,000 to 5,000 patients globally, according to National Institutes of Health data.
Redemplo uses RNA-based technology to reduce the production of apolipoprotein C-III, a protein that helps regulate fat metabolism.
Ionis Pharmaceuticals’ drug Tryngolza is also approved to treat the condition. It was launched in December 2024 and brought in $32 million in the third quarter of 2025.
Arrowhead and Ionis have filed dueling lawsuits against each other, with Ionis alleging Redemplo infringes its RNA-targeting patent, while Arrowhead seeks a court ruling that the patent is invalid.
“We think Arrowhead’s drug will capture a larger market share,” B. Riley Securities analyst Madison El-Saadi said ahead of the decision, adding Redemplo has a better profile compared to Ionis’ Tryngolza.
Analysts on average expect the drug to bring about $1.4 billion by 2031, according to data compiled by LSEG.
Arrowhead has partnered with Sanofi for Redemplo, giving the French drugmaker exclusive rights to develop and commercialize the drug in Greater China.
Shares of the company were halted in morning trading.
(Reporting by Padmanabhan Ananthan and Christy Santhosh in Bengaluru; Editing by Tasim Zahid and Vijay Kishore)
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