MHRA approves gene-editing therapy Casgevy for children aged five and older

What was announced

The UK Medicines and Healthcare products Regulatory Agency (MHRA) granted a marketing authorisation extension for Casgevy on 29 October 2026. The therapy, also known as exagamglogene autotemcel, was developed by Vertex Pharmaceuticals (Europe) Ltd.

This decision lowers the minimum age for receiving Casgevy from 12 years old down to five years old. Eligible patients must have severe sickle-cell disease or transfusion-dependent beta-thalassemia. Julian Beach, Executive Director of Operations at the MHRA, said the approval followed an assessment of evidence covering safety, quality, and effectiveness.

What it means

Severe sickle-cell disease and beta-thalassemia are inherited blood disorders. Both stem from faults in the genetic code for haemoglobin, which red blood cells rely on to transport oxygen throughout the body. People with severe sickle cell can experience intense pain, life-threatening infections, and anaemia. People with beta-thalassemia often require blood transfusions every three to five weeks alongside regular medicines.

Casgevy relies on gene editing, a technique that alters specific sequences of DNA. Doctors harvest bone marrow stem cells from the patient, modify the target gene in a laboratory, and then return the modified cells through an infusion. Before the infusion happens, patients receive conditioning treatment to prepare their bone marrow.

After receiving the modified stem cells, patients stay in hospital while their bone marrow creates red blood cells containing working haemoglobin. Known side effects include fever, fatigue, nausea, and an increased risk of infection. The regulator said it will continue to monitor the safety of the medicine.

What the announcement does not tell us

The MHRA did not explain how much the treatment costs or whether the NHS will cover it for eligible children. It also did not publish full clinical trial data or details about how long patients stay in hospital during conditioning and recovery. Furthermore, the agency did not state how many children aged five to 11 in the UK are currently eligible. Readers will need to check the Summary of Product Characteristics and Patient Information leaflets, which the MHRA said it would publish on its website within seven days of the approval.