The Food and Drug Administration (FDA) is expected to approve the CRISPR treatment used for sickle cell disease in patients aged 12 years and older. This treatment, called “Casgevi,” is the first of its kind to use the powerful gene-editing tool CRISPR to target the underlying cause of sickle cell disease.
Key Information
Sickle cell disease, also known as sickle cell anemia, is a group of inherited blood disorders that affects the body’s ability to produce functional hemoglobin, the protein responsible for transporting oxygen in red blood cells throughout the body. The genetic mutation responsible for sickle cell disease means that red blood cells become rigid or crescent-shaped, which can obstruct blood vessels and prevent oxygen transport in the body, leading to serious and potentially life-threatening issues such as severe pain, stroke, and organ damage.
Clinical Trials and Expectations
Clinical trials of the treatment suggest that “Casgevi,” given as a one-time therapy, can help alleviate symptoms and provide hope for a cure for a condition that has far surpassed the risky processes of bone marrow transplant. It is estimated that about 100,000 people suffer from sickle cell disease across the United States, with most being Black.
Amazing Facts
Although “Casgevi” edits DNA inside the human body, it does not actually fix the root cause of sickle cell disease. Instead of repairing the mutation responsible for producing faulty hemoglobin, “Casgevi” targets the genes responsible for producing a different type of hemoglobin that is usually shut down shortly after birth. This genetic solution stimulates the production of naturally suppressed fetal hemoglobin in the body, helping red blood cells maintain their healthy, disc shape. Although the treatment is given once, the entire process can take months and includes laboratory work to modify blood cells and recovery in the hospital after injecting modified cells into patients.
Main Background
The expected FDA decisions come after weeks of the medical authority in Britain giving the green light to “Casgevi,” becoming the first regulatory body in the world to approve a treatment using CRISPR technology. At that time, Vertex’s CEO and President Reshma Kewalramani celebrated the approval, stating it was “a historic day in science and medicine.” The journey of CRISPR to the clinic has been swift since its discovery and laboratory use. This tool, derived from bacterial immune systems, was discovered just over a decade ago, and the discovery was awarded the Nobel Prize in Chemistry in 2020. By allowing scientists to manipulate DNA with precision – the tool is often described as a pair of genetic scissors – it was quickly welcomed as a transformative tool across the life sciences, with potential applications including transferring traits such as disease resistance across species, editing defective genes in medical practice, or even resurrecting extinct animals. Although there are clear benefits, experts warn that the technology is a double-edged sword. For example, while CRISPR can be used to make a virus harmless to humans, it can also be used to design a more virulent pathogen. The potential to modify human DNA also raises the prospect of enhancements designed to improve rather than repair genes, a potential slippery slope toward racial productivity.
What to Watch For
The medical authority in the UK has approved “Casgevi” for treating beta-thalassemia (β-thalassemia) in addition to sickle cell disease. Beta-thalassemia is another inherited blood disorder characterized by hemoglobin production. The FDA is also considering the treatment for beta-thalassemia and is expected to make a decision by the end of March next year.
What
We do not know it
When considering the treatment, FDA advisers who endorsed the therapy expressed confidence in the drug’s effectiveness and benefits but warned about the theoretical consequences of human genetic modifications. Due to the newness of the technology and its use in the clinic, experts caution that there may be unintended results with unknown consequences, for instance, if the treatment leads to genetic modifications in other places (known as off-target modifications). The British medical authority confirmed that it found no significant safety concerns and stated that the safety of “Casgevi” will be closely monitored post-approval.
Further Reading
The UK approves the first gene-editing treatment using CRISPR technology (Forbes)
Is CRISPR technology safe? Gene editing gets its first check from the FDA (Nature)
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