Health officials are on the verge of approving a treatment, the first of its kind, for tens of thousands of Americans suffering from a debilitating blood disorder.
Last month, an advisory committee to the Food and Drug Administration (FDA) announced that it would consider approving the gene-editing drug Casgevy to treat sickle cell disease, a lifelong, excruciatingly painful condition that deforms blood cells.
The drug was recently approved in Britain for the treatment of sickle cell and transfusion-dependent β-thalassemia – a deficiency of red blood cells that leads to severe anemia. It is expected to cost the British government about £1 million ($1.25 million) per patient.
If the U.S. committee recommends the drug for sickle cell disease, the FDA will vote on approval in December.
Casgevy would give new hope to the 100,000 Americans with sickle cell disease, which is currently only approved to be cured by a bone marrow transplant.
Patients with sickle cell disease, of which there are about 100,000 in the U.S., do not properly produce hemoglobin — a substance in red blood cells that transport oxygen throughout the body. As a result, their red blood cells become stiff and form a crescent shape (pictured) instead of a disk, which can cause them to die and become stuck in blood vessels.
Casgevy, made by Boston-based Vertex Pharmaceuticals (pictured) and Crispr Therapeutics in Switzerland, works by editing the defective HBB gene behind both conditions in a patient’s bone marrow stem cells so that the body produces functioning hemoglobin.
A bone marrow transplant is a procedure in which healthy blood-forming stem cells from a donor are transplanted to replace bone marrow in the patient that is not producing enough healthy cells.
Stem cells are the ‘raw materials’ of the body, or cells that can develop into many different specialized cell types. They can be used to repair damaged tissue, and researchers believe stem cell therapies could one day treat conditions like Alzheimer’s disease and paralysis.
In most cases of a bone marrow transplant, the donor is a brother or sister, but even a brother or sister has only a one in four chance of being a match for the patient. And often transplants are not performed because of the risks, including the transplanted cells attacking other cells in the recipient’s body, which can be life-threatening.
There are more than 30 FDA-approved gene therapies used to treat various types of cancer and the blood disease hemophilia. However, many are largely inaccessible due to the high cost.
Last year, the US approved the gene-manipulating drug Hemgenix for hemophilia, a bleeding disorder in which the blood does not clot properly. The drug costs $3.5 million per dose, making it the most expensive drug in the world.
Casgevy is the first licensed drug to use the innovative gene-editing tool CRISPR, known as ‘genetic scissors’, which allows scientists to make precise changes to DNA. Its inventors received the Nobel Prize in 2020.
The drug, made by Boston-based Vertex Pharmaceuticals and Crispr Therapeutics in Switzerland, works by editing the defective HBB gene that causes sickle cell disease in a patient’s bone marrow stem cells so that the body produces properly functioning hemoglobin, the protein in red blood cells which is responsible for producing sickle cell disease. delivering oxygen to tissues throughout the body.
To do this, stem cells are taken from a patient’s bone marrow and processed in a laboratory using molecular ‘scissors’, which precisely switch off the defective gene.
Stem cells are then injected back into the patient, who may have to spend a month or more in the hospital while the treated cells start making healthy red blood cells.
Scientists believe the results have the potential to be lifelong.
An ongoing study of the drug to date shows that 97 percent of sickle cell patients were free of severe pain for at least a year after treatment.
Sickle cell disease is the umbrella term for a group of hereditary conditions that seriously affect red blood cells.
It affects 100,000 Americans and 15,000 Britons, most of whom are black.
Healthy red blood cells – produced by stem cells in the bone marrow – are round, hollow discs that bend and bend easily.
However, in people with sickle cell disease, defective stem cells produce red blood cells that are crescent-shaped.
They are stiff, cannot penetrate smaller blood vessels and are prone to blockages that deprive parts of the body of oxygen.
John James OBE, CEO of the Sickle Cell Society of Britain, said: ‘Sickle cell disease is an incredibly debilitating condition, causing significant pain for those living with it and potentially leading to premature death.
‘There are currently limited medicines available to patients, so I welcome today’s news that a new treatment has been assessed as safe and effective, which has the potential to significantly improve the quality of life for so many.’
Jimi Olaghere, 36, who lives in the Atlanta area, Georgia, has suffered from sickle cell disease since childhood and was hospitalized almost every month.
The technology entrepreneur told the BBC the condition felt like “shards of glass running through your veins or someone taking a hammer to your joints.”
“You wake up in the morning in pain and you go to bed in pain.”
However, Mr Olaghere became one of the first patients to undergo the revolutionary new gene editing treatment as part of Vertex Pharmaceuticals and Crispr Therapeutics clinical trials in the US in 2020.
He said he woke up without any pain and it was “like being born again.”
“I look back and think, ‘Wow, I can’t believe I lived with that.'”
If the FDA panel recommends the treatment, the agency will decide on Dec. 8 whether to approve it.