Thousands of Brits suffering from two blood disorders could be given a first-of-its-kind treatment that could potentially cure them.
Casgevy was Thursday approved by the UK‘s medicines watchdog for all over-12s after ‘rigorous’ safety, quality and effectiveness checks.
Who benefits from the drug
The drug, which is expected to be priced around £1million per patient, treats sickle cell disease and transfusion-dependent β-thalassemia — painful, life-long conditions that, in severe cases, can be fatal.
What experts say
Experts say the gene-editing treatment acts as a ‘functional cure’ for both disorders, removing the faulty gene and relieving symptoms.
However, it will only be rolled out on the NHS if it receives a further approval from the National Institute for Health and Care Excellence (Nice).
What cause some genetic conditions
Both genetic conditions are caused by errors in the genes for haemoglobin, which is used by red blood cells to carry oxygen around the body.
Sickle cell disease patients, of which there are around 15,000 in the UK, do not make haemoglobin properly — a substance in red blood cells, which carry oxygen around the body.
As a result, their red blood cells become rigid and shaped like a crescent instead of a disc, which can cause them to die and become stuck in blood vessels.
Sufferers experience attacks of severe pain that can last days or weeks, serious and life-threatening infections and anaemia, which can trigger tiredness and weakness.
Around 1,000 Brits have transfusion-dependent β-thalassaemia. This group have a shortage of healthy red blood cells, which leads to severe anaemia.
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They often need a monthly blood transfusion to survive and require injections and medicines for life. If left untreated, the condition can cause organ damage and be fatal.
How does Casgevy work?
Casgevy, made by Boston-based Vertex Pharmaceuticals and Crispr Therapeutics in Switzerland, works by editing the faulty HBB gene behind both conditions in a patient’s bone marrow stem cells so that the body produces functioning haemoglobin.
To do this, stem cells are taken out of a patient’s bone marrow and edited in a laboratory using molecular ‘scissors’ which precisely disable the faulty gene.
Stem cells are then infused back into the patient, who may need to spend a month or longer in hospital while the treated cells start to make healthy red blood cells.
Testimonials
The results have the potential to be life-long. An ongoing trial of the drug so far shows that 97 per cent of sickle cell patients were free from severe pain for at least one year after treatment.
In a separate study for β-thalassaemia, 93 per cent of participants did not need a blood transfusion for at least one year.
Side effects
Among those who did, their need for transfusions fell by 70 per cent. Side effects included nausea, fatigue, fever and increased risk of infection.
