MHRA lowers Casgevy age limit to five: what changes for sickle-cell patients

The UK medicines regulator has lowered the age at which patients can receive the country's first approved CRISPR-based therapy. On 30 October 2026, the Medicines and Healthcare products Regulatory Agency extended the UK authorisation of Casgevy (exagamglogene autotemcel) to children aged five and over with severe sickle-cell disease and transfusion-dependent beta-thalassemia. The therapy had previously been authorised only for patients aged 12 and over.

Casgevy is the first approved therapy to use CRISPR/Cas9 gene-editing technology. It works by editing a faulty gene in a patient's bone marrow stem cells, which are then infused back into the patient. The science is not new. What changed is the eligible age — and that is a regulatory and access decision, not a laboratory breakthrough.

Sickle-cell disease and beta-thalassemia are lifelong inherited conditions caused by genetic changes affecting haemoglobin. Severe sickle-cell disease can cause episodes of intense pain, anaemia and an increased risk of serious, potentially life-threatening infections. About 15,000 people in the UK have sickle-cell disease, almost all of African or Caribbean heritage.

Lowering the age threshold means children who meet the criteria could potentially receive a functional cure earlier, before years of transfusions and accumulated organ damage. The word "potentially" matters: the therapy is described as a potential functional cure, not a guaranteed one. A sixteen-year-old patient with beta-thalassemia was freed from lifelong blood transfusions after receiving a pioneering gene-editing treatment, according to reports.

The approval is UK-specific; it does not govern use in younger children elsewhere.

For families, the practical takeaway is narrow but real: children aged five and over with severe sickle-cell disease or transfusion-dependent beta-thalassemia may now be assessed for a therapy that was previously out of reach until age 12.