Approval of Plozasiran for Rare Condition
On 19 October 2026, the Medicines and Healthcare products Regulatory Agency (MHRA) granted approval for plozasiran (marketed as Redemplo) to help lower triglyceride levels in adults diagnosed with familial chylomicronaemia syndrome (FCS), in conjunction with a low-fat diet.
FCS is an uncommon disorder characterised by significantly elevated triglyceride levels in the bloodstream, which can trigger severe complications, including inflammation of the pancreas, known as pancreatitis. This condition often results in intense abdominal pain and other serious health issues.
Mechanism of Action
Plozasiran functions by inhibiting the production of apolipoprotein C3, a hepatic protein that hampers the breakdown of fats. By diminishing the synthesis of this protein, the drug effectively contributes to lowering triglyceride concentrations in the blood.
The treatment is administered through a subcutaneous injection of 25 mg every three months. Training is provided for patients or their caregivers, enabling them to self-administer the injection comfortably.
Clinical Trial Insights
Julian Beach, Executive Director of Operations, highlighted that this authorisation introduces a valuable treatment avenue for adults suffering from FCS, a condition that can lead to debilitating complications. He noted that clinical trial evidence demonstrated a significant reduction in triglyceride levels when plozasiran was paired with a controlled diet.
The authorisation is based on a pivotal study involving 75 adults with FCS. Participants adhered to a controlled diet, with 50 individuals receiving plozasiran and the remaining 25 receiving a placebo. After a 10-month period, those treated with plozasiran exhibited a median triglyceride level reduction of approximately 80%, in stark contrast to the 17% reduction observed in the placebo group. Furthermore, the trial indicated a decreased incidence of acute pancreatitis among those receiving plozasiran.
Potential Side Effects and Monitoring
The primary side effect associated with plozasiran is hyperglycaemia, or elevated blood sugar levels, which may affect more than 10% of users. Other commonly reported side effects, which may impact up to 10% of patients, include headaches, nausea, and localised reactions at the injection site.
Individuals who suspect they may be experiencing side effects are encouraged to consult with their healthcare provider, pharmacist, or nurse, and to report any concerns directly through the Yellow Card scheme, available at https://yellowcard.mhra.gov.uk or via the MHRA Yellow Card app.
Regulatory Background and Further Information
The marketing authorisation for plozasiran was awarded to Arrowhead Pharmaceuticals Ireland Limited on 19 October 2026. The approval was facilitated through the International Recognition Procedure (IRP), Route B, with the European Medicines Agency (EMA) serving as the reference regulator.
Comprehensive details are available in the Summary of Product Characteristics (SmPC) and the Patient Information Leaflet (PIL), which will be accessible on the MHRA Products website in the near future.
The MHRA plays a crucial role in overseeing all medicines and medical devices within the UK, ensuring their efficacy and safety. This commitment is founded on thorough and evidence-based evaluations to guarantee that the therapeutic benefits outweigh any associated risks.
The MHRA operates as an executive agency under the Department of Health and Social Care.
For further media inquiries, please reach out via email at newscentre@mhra.gov.uk or call 020 3080 7651.