As with any medicine, the MHRA will keep the safety and effectiveness of mirdametinib under close review.
The Medicines and Healthcare products Regulatory Agency (MHRA) has today (11 December 2025) approved the medicine mirdametinib (Ezmekly) for the treatment of plexiform neurofibromas in adults and adolescents. It is the first treatment for children as young as 2 years old with a genetic condition called neurofibromatosis type 1 (NF1).
NF1 is a rare genetic condition that can cause tumours to form on nerves throughout the body. These tumours, known as plexiform neurofibromas, may grow and press on nearby tissues, sometimes causing pain or problems with daily activities.
Mirdametinib works by blocking certain signals in the body that would otherwise allow these tumours to grow. It is available as a dispersible tablet, which can be swallowed whole or dissolved in water. This makes it suitable for patients unable or unwilling to swallow a capsule and particularly suitable for children under 6 years of age.
Julian Beach, MHRA Interim Executive Director, Healthcare Quality and Access, said:
"The approval of mirdametinib provides the first treatment for NF1 that can be used for children aged as young as 2 years and older. Keeping patients safe and enabling their access to high quality, safe and effective medical products are key priorities for us.
"As with all licensed medicines, we will continue to monitor its safety and effectiveness closely."
A full list of side effects can be found in the Patient Information Leaflet (PIL) or the Summary of Product Characteristics (SmPC), which will be published on the MHRA website within 7 days of approval.
Anyone who suspects they are having a side effect from this medicine are encouraged to talk to their doctor, pharmacist or nurse and report it directly to the Yellow Card scheme, either through the website ( https://yellowcard.mhra.gov.uk/ ) or by searching the Google Play or Apple App stores for MHRA Yellow Card.
Notes
Marketing authorisation approval was granted on 11 December 2025 to SpringWorks Theraputics Ireland Limited.
At the time of approval, only one medicine was authorised in the UK for plexiform neurofibromas in patients aged three years and older with NF1. Mirdametinib provides an additional treatment option and has been shown to be effective in patients from a slightly younger age, starting at 2 years of age.
