A new treatment for sickle-cell disease and transfusion-dependent
β-thalassemia has been authorised by the Medicines and Healthcare
products Regulatory Agency (MHRA) for patients aged 12 and over
after a rigorous assessment of its safety, quality and
effectiveness.
Casgevy is the first medicine to be licensed that uses the
innovative gene-editing tool CRISPR, for which its inventors were
awarded the Nobel Prize in 2020.
Both sickle cell disease and β-thalassemia are genetic conditions
caused by errors in the genes for haemoglobin, which is used by
red blood cells to carry oxygen around the body. Sickle cell
disease is particularly common in people with an African or
Caribbean family background. β-thalassemia mainly affects people
of Mediterranean, south Asian, southeast Asian and Middle Eastern
origin.
In people with sickle cell disease, this genetic error can lead
to attacks of very severe pain, serious and life-threatening
infections, and anaemia (whereby your body has difficulty
carrying oxygen).
In people with β-thalassaemia, it can lead to severe anaemia.
Patients often need a blood transfusion every 3 to 5 weeks, and
injections and medicines throughout their lives.
Casgevy is designed to work by editing the faulty gene in a
patient’s bone marrow stem cells so that the body produces
functioning haemoglobin. To do this, stem cells are taken out of
bone marrow, edited in a laboratory and then infused back into
the patient after which the results have the potential to be
life-long.
Beach, Interim Executive Director
of Healthcare Quality and Access at the MHRA
said:
Both sickle cell disease and β-thalassemia are painful, life-long
conditions that in some cases can be fatal. To date, a bone
marrow transplant – which must come from a closely matched donor
and carries a risk of rejection – has been the only permanent
treatment option.
I am pleased to announce that we have authorised an innovative
and first-of-its-kind gene-editing treatment called Casgevy,
which in trials has been found to restore healthy haemoglobin
production in the majority of participants with sickle-cell
disease and transfusion-dependent β -thalassaemia, relieving the
symptoms of disease.
The MHRA will continue to closely monitor the safety and
effectiveness of Casgevy, through real-world safety data and
post-authorisation safety studies being carried out by the
manufacturer.
I would like to thank the patients with lived experiences who
engaged with us as part of the assessment process and gave us
valuable insight into their lives and the challenges of managing
their condition.
John James OBE, Chief Executive of the Sickle Cell
Society said:
Sickle cell disorder is an incredibly debilitating condition,
causing significant pain for the people who live with it and
potentially leading to early mortality.
There are limited medicines currently available to patients, so I
welcome today’s news that a new treatment has been judged safe
and effective, which has the potential to significantly improve
the quality of life for so many.
Trial results
In the clinical trial for sickle-cell disease, 45 patients have
currently received Casgevy but only 29 patients have been in the
trial long enough to be eligible for the primary efficacy interim
analysis. Of these eligible patients, 28 (97%) were free of
severe pain crises for at least 12 months after
treatment.
In the clinical trial for transfusion-dependent β-thalassemia, 54
patients have currently received Casgevy but only 42 patients
have been in the trial long enough to be eligible for the primary
efficacy interim analysis. Of these, 39 (93%) did not need a
red blood cell transfusion for at least 12 months after
treatment. The remaining three had more than a 70% reduction in
the need for red cell transfusions.
Side effects from treatment were similar to those associated with
autologous (from a person’s own cells) stem cell transplants,
including (but not limited to) nausea, fatigue, fever and
increased risk of infection.
No significant safety concerns were identified during the trials.
Safety continues to be closely monitored by the MHRA and the
manufacturer.
Both trials are ongoing and further results will be made
available in due course.
Administration
Casgevy is administered by taking stem cells out of a patient’s
bone marrow and editing a gene in the cells in a laboratory.
Patients must then undergo conditioning treatment to prepare the
bone marrow before the modified cells are infused back into the
patient. After that, patients may need to spend at least a month
in a hospital facility while the treated cells take up residence
in the bone marrow and start to make red blood cells with the
stable form of haemoglobin.
The decision to authorise Casgevy has been endorsed by the
government’s independent scientific advisory committee, the
Commission on Human Medicines, after a robust review of the
available evidence.
Notes to Editors
- The new indication was granted on 15 November 2023 to Vertex
Pharmaceuticals (Europe) Ltd and CRISPR Therapeutics.
- Approximately 15,000
people in the UK have sickle cell disorder.
- More information can be found in the Summary of Product
Characteristics and Patient Information leaflets which will be
published on the MHRA
Products website within 7 days of approval.
