Four injections a year, and an 80% fall in a blood fat the body cannot clear
What happened
On Monday 19 October 2026, the UK's medicines regulator authorised a new treatment for a very rare inherited condition. The Medicines and Healthcare products Regulatory Agency (MHRA) approved plozasiran, which will be sold under the brand name Redemplo. It is for adults with familial chylomicronaemia syndrome. Almost everyone shortens that to FCS. FCS stops the body clearing a type of fat called triglycerides out of the blood. In most people, triglycerides rise after a meal and then fall away. In someone with FCS, they can stay extremely high. That can inflame the pancreas, a gland that sits behind the stomach. Pancreatitis is painful, and it can put people in hospital. The new medicine is given as a 25mg injection under the skin, once every three months. That is four injections a year. After training, a patient or a carer can give it at home. The authorisation was granted through the International Recognition Procedure, with the European Medicines Agency acting as the reference regulator. The licence is held by Arrowhead Pharmaceuticals Ireland Limited. Julian Beach, the MHRA's Executive Director of Operations, said the decision offers "an additional treatment option for adults with familial chylomicronaemia syndrome", and that trial data showed plozasiran "substantially reduced triglyceride levels when used alongside a controlled diet". He added that the agency will keep monitoring the medicine's safety.
Why this matters
FCS is rare. Most people reading this will never meet someone who has it. So why does a decision like this matter? First, because of what the condition does to a life. Until now, the main defence has been a very strict low-fat diet. Not a sensible, healthy-eating sort of low-fat. A severe one, kept up every day, for life, often with fat cut to a small fraction of what most of us eat. Even then, attacks of pancreatitis can still happen. People describe planning holidays, weddings and school trips around the risk of ending up in hospital. Second, because of how the medicine works. Plozasiran switches off the liver's production of a protein called apolipoprotein C3. That protein acts like a brake on the body's fat-clearing machinery. Take the brake off, and triglycerides fall. This is a newer style of medicine that works on the instructions a cell uses, rather than on the finished protein. Third, because of the pattern. Over the past few years, UK regulators have licensed a run of treatments for conditions that affect only small numbers of people. Rare disease groups have argued for years that small does not mean unimportant. Decisions like this one suggest the argument is landing.
What the evidence actually says
It is worth being precise here, because the headline number sounds dramatic. The main study enrolled 75 adults with FCS. Fifty received plozasiran and 25 received a placebo, which is a dummy injection. Everybody in the trial, including the placebo group, followed a controlled diet. After 10 months, the plozasiran group had a median drop in triglycerides of around 80%. The placebo group dropped around 17%. People taking plozasiran also had fewer episodes of acute pancreatitis. Now the limits. Seventy-five people is a small trial by most standards. It is small because the condition is rare, not because anyone cut corners, but it still means less information about uncommon side effects than you would get from a study of thousands. The known side effects are listed. The most common is hyperglycaemia, meaning raised blood sugar, which may affect more than 1 in 10 people. Up to 1 in 10 may get headache, nausea, or a reaction where the injection goes in. The diet does not go away. The licence is for use alongside a low-fat diet, not instead of one. And the MHRA has been explicit that it will carry on watching the safety data through the Yellow Card scheme, which anyone in the UK can use to report a suspected side effect.
Practical advice
If none of this applies to you, the useful thing to take away is simply that very high triglycerides are a real medical problem, not just a line on a blood test. If you or someone close to you has FCS, or is being investigated for very high triglycerides: Ask your specialist, not the internet, whether this medicine is relevant to you. FCS is a specific genetic diagnosis. Raised triglycerides from diet, alcohol, diabetes or other causes is a different situation, and this licence does not cover it. An MHRA authorisation is not the same as NHS funding. A medicine can be licensed as safe and effective before decisions are made about who can get it on the NHS and where. Expect that to take longer, and ask your clinic what the current position is. Keep the diet going unless a specialist tells you otherwise. That is how the medicine was tested. The full Summary of Product Characteristics and the Patient Information Leaflet will appear on the MHRA Products website. Those are the documents to read before an appointment, rather than news coverage. If you have a side effect you think might be from a medicine, report it through the Yellow Card scheme, online or in the app. Reports from patients, not just doctors, are part of how problems get spotted early.
What to know
On 19 October 2026 the MHRA authorised plozasiran (Redemplo) for adults with familial chylomicronaemia syndrome, a rare inherited condition in which triglycerides build up in the blood and can inflame the pancreas. It is a 25mg injection under the skin every three months, used alongside a low-fat diet. In a trial of 75 adults, triglycerides fell by a median of about 80% on plozasiran against about 17% on placebo, and there were fewer episodes of acute pancreatitis. The most common side effect is raised blood sugar. A licence is not the same as NHS availability, so anyone affected should ask their specialist what happens next. Sources: MHRA / GOV.UK, "MHRA authorises plozasiran (Redemplo) for adults with familial chylomicronaemia syndrome", 19 October 2026, https://www.gov.uk/government/news/mhra-authorises-plozasiran-redemplo-for-adults-with-familial-chylomicronaemia-syndrome ; Arrowhead Pharmaceuticals, "Arrowhead Pharmaceuticals Announces FDA Approval of REDEMPLO (plozasiran) to Reduce Triglycerides in Adults with Familial Chylomicronemia Syndrome (FCS)", 18 November 2025, https://ir.arrowheadpharma.com/news-releases/news-release-details/arrowhead-pharmaceuticals-announces-fda-approval-redemplor ; HCPLive, "FDA Approves Plozasiran for Adults With Familial Chylomicronemia Syndrome", November 2025, https://www.hcplive.com/view/fda-approves-plozasiran-for-adults-with-familial-chylomicronemia-syndrome This article is for general information and does not replace advice from a doctor, pharmacist or other qualified healthcare professional.
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