NHS England has approved Casgevy (exagamglogene autotemcel), the first gene-editing therapy using CRISPR technology, for treating severe beta thalassaemia in patients aged 12 and older. The National Institute for Health and Care Excellence (NICE) approved the treatment on August 8, 2024, making the NHS among the first healthcare systems worldwide to offer this revolutionary therapy.
Clinical Efficacy and Patient Impact
International clinical trials demonstrated remarkable efficacy, with 93% of patients with beta thalassaemia not requiring blood transfusions for at least a year after treatment. In the most recent trial data, 49 out of 52 patients treated did not need another blood transfusion for at least a year of monitoring. The therapy offers hope of a lifetime cure for patients who typically require blood transfusions every 3-5 weeks to survive.
Beta thalassaemia is an inherited blood disorder affecting red blood cells' ability to carry oxygen throughout the body. The condition primarily affects people of Mediterranean, South Asian, Southeast Asian, and Middle Eastern backgrounds. In the UK, approximately 2,300 people live with thalassaemia, with an estimated 800 having the severe form requiring regular blood transfusions.
Treatment Mechanism and Process
The therapy works by editing genes in a patient's bone marrow stem cells using CRISPR technology, which won the Nobel Prize for Chemistry in 2020. Rather than repairing the genetic defect directly, Casgevy disables a genetic switch called BCL11A, allowing the adult body to produce fetal haemoglobin instead of the defective adult haemoglobin affected by beta thalassaemia.
The treatment process involves extracting blood stem cells from the patient's body, editing them in a laboratory using CRISPR technology, and returning the treated cells via infusion. Patients must receive chemotherapy before treatment to eliminate old stem cells, followed by a 4-6 week hospital stay to allow the treated stem cells to embed in the bone marrow and begin producing healthy red blood cells.
Patient Experiences and Quality of Life Impact
Kirthana Balachandran, a 21-year-old medical student from West London diagnosed at three months old, described the potential impact: "Gene therapy would mean a lot to me – it would be a life-changing treatment. I'm only 21 and the idea of depending on transfusions for quite literally the rest of my life is daunting."
Abdul-Qadeer Akhtar, 28, from Hemel Hempstead, received the therapy as part of a clinical trial in 2020. He reported significant improvements: "My overall health and quality of life have significantly improved. I'm gaining more from my workouts and have even taken up boxing. I can travel more freely now, which is fantastic – I'm eager to embrace life to the fullest."
Healthcare System Implementation
The therapy will be offered at seven highly specialist NHS centres across England within weeks, with manufacturing taking place in Edinburgh. An estimated 460 patients in England currently living with transfusion-dependent beta thalassaemia, aged 12 and older, are potentially eligible for the treatment.
NHS England has negotiated a deal with manufacturer Vertex through its Innovative Medicines Fund (IMF), providing fast-tracked access while gathering additional evidence over the next five years. The official price tag of £1.6 million per patient has been reduced through NHS negotiations, though specific pricing details were not disclosed.
Clinical Significance and Future Outlook
Beta thalassaemia is a life-limiting condition, with many patients not expected to live beyond their 50s. The disorder requires lifelong treatment and significantly impacts quality of life, causing anaemia, chronic pain, and psychological effects including anxiety and depression. Previously, the only curative treatment was stem cell transplant, available to only a small number of patients due to difficulties finding matched donors and risk of rejection.
Amanda Pritchard, NHS chief executive, stated: "This is a historic moment for people living with beta thalassaemia with a potential cure for those facing this debilitating disorder now available on the NHS. This therapy offers people a life free from that as well as the hope of living longer, which is truly amazing news."
The approval represents the latest in a series of revolutionary gene therapies secured by NHS England over the past five years. Negotiations are currently underway to potentially extend the same therapy to treat sickle cell anaemia, another genetic disease affecting haemoglobin.
