The Medicines and Healthcare products Regulatory Agency (MHRA) has today, 3 June 2026, announced the authorisation of resmetirom (Rezdiffra) for the treatment of adult patients diagnosed with metabolic dysfunction-associated steatohepatitis (MASH). This decision marks a significant development for patients in the United Kingdom grappling with this chronic and progressive liver condition, for which there have previously been no specific approved medicinal treatments.
MASH, formerly known as non-alcoholic steatohepatitis (NASH), is a more severe form of metabolic dysfunction-associated fatty liver disease (MAFLD). It is characterised by inflammation and liver cell damage, which can lead to fibrosis, cirrhosis, liver failure, and an increased risk of liver cancer. The condition is often linked to obesity, type 2 diabetes, and high cholesterol, and its prevalence has been rising in the UK, mirroring global trends in metabolic disorders.
Resmetirom works by targeting a specific thyroid hormone receptor in the liver, which plays a crucial role in regulating metabolism and reducing liver fat and inflammation. Clinical trials have demonstrated its effectiveness in improving liver histology, including reducing liver fat and fibrosis, in a significant proportion of MASH patients. The MHRA's authorisation is based on a thorough review of the drug's safety and efficacy data, concluding that its benefits outweigh potential risks for the specified patient group.
The approval of Rezdiffra is expected to offer a much-needed therapeutic option for individuals who currently rely on lifestyle modifications, such as diet and exercise, to manage their condition. While these changes remain fundamental, the introduction of a targeted pharmacological treatment could significantly alter the disease progression for many, potentially preventing the need for liver transplants in some cases. This development is particularly pertinent given the substantial burden MASH places on the NHS, both in terms of direct patient care and the long-term management of complications.
The availability of Rezdiffra will now depend on subsequent decisions regarding its funding and access within the NHS, which typically involves an appraisal by the National Institute for Health and Care Excellence (NICE). NICE will evaluate the cost-effectiveness of resmetirom, a process that can take several months, before making recommendations on its use in England. Similar processes will follow in Scotland, Wales, and Northern Ireland.
The Department of Health and Social Care has yet to comment on the broader implications for public health policy, but patient advocacy groups have welcomed the MHRA's decision, highlighting the unmet medical need for MASH patients. They anticipate that this authorisation will stimulate further research and development in the field of liver disease, ultimately leading to more treatment options for a condition that affects millions globally.
Source: Medicines and Healthcare products Regulatory Agency (MHRA)