Britain’s medicines regulator has approved a groundbreaking treatment for two painful and debilitating lifelong blood disorders that works by “editing” the gene that causes them.
It is the world’s first approved drug that works by deploying gene editing using the “genetic scissors”, known as CRISPR, for which its inventors won the Nobel Prize in Chemistry.
Casgevy’s developers hope this innovative treatment could banish the pain, infections and anemia that sickle cell disease causes, as well as the severe anemia experienced by people with beta thalassemia.
In the UK, around 15,000 people, almost all of African or Caribbean origin, have sickle cell disease. Around 1,000 people – mainly from the Mediterranean, South Asia, Southeast Asia and the Middle East – suffer from beta thalassemia and need regular blood transfusions to treat their anemia .
Experts in the field hope that Casgevy could be a cure, making it more necessary for people with these diseases to undergo bone marrow transplants. Until now, this was the only treatment available, although the body could reject the donor marrow.
The Sickle Cell Society hailed the MHRA’s decision as “a historic moment for the sickle cell community” which “offers them new hope and optimism”.
The charity added that the approval of Casgevy, made by Vertex Pharmaceuticals, “enables the NHS to use it as a revolutionary therapeutic intervention for those struggling with this disease, (which is) marked by chronic anemia , recurrent episodes of intense pain requiring hospitalization. , organ damage, high risk of stroke and premature mortality.”
Sickle cell disease and beta thalassemia are genetic or inherited diseases caused by errors in the genes for hemoglobin, a protein that allows red blood cells to carry oxygen throughout the body. Both conditions can be fatal.
The MHRA said: “Casgevy is designed to work by modifying the faulty gene in a patient’s bone marrow stem cells so that the body produces functional hemoglobin. To do this, stem cells are extracted from bone marrow, edited in the laboratory, then reinfused into the patient, after which the results can potentially last a lifetime.
During this process, laboratory staff use “genetic scissors” to modify or cut the DNA of the patient’s bone marrow cells, before the treated cells are re-infused.
The MHRA said patients may have to spend at least a month in hospital while the treated cells “settle in the bone marrow and begin to make red blood cells containing the stable form of hemoglobin”.
In a clinical trial of Casgevy for sickle cell disease, 28 of 29 patients did not experience any major pain episodes – which could lead to hospitalization – for at least a year afterwards.
When the treatment was used for people with beta thalassemia, 39 of 42 trial participants did not need a red blood cell transfusion for at least 12 months after receiving Casgevy.
Dr Sara Trompeter, consultant haematologist at University College Hospital, London and an expert in sickle cell disease, said: “While curative treatments may not be suitable for everyone, gene therapy offers a real chance of cure for those who do not. are not eligible for bone marrow transplants. and so we are delighted that it has been approved by the MHRA.