FDA authorizes the use of “CRISPR scissors” to treat sickle cell disease

On Friday, US health authorities approved the first treatment using the “CRISPR” molecular scissors, a gene editing technology (rewriting genetic material) that represents a major achievement in medicine, and in this case it is expected to alleviate the suffering of those suffering from a rare blood disease.

In total, two treatments have been approved against sickle cell anemia, a rare inherited genetic disease that affects about 100,000 people in the United States.

“These treatments represent a major advance in the field of gene therapy for patients suffering from sickle cell anemia, a rare and debilitating blood disease,” Peter Marks, a senior official at the US Food and Drug Administration (FDA), said during a press conference.

“The potential of these products to change the lives of patients suffering from sickle cell disease is enormous,” he added.

The US agency confirmed that this disease particularly affects Americans of African descent.

Nobel Prize in Chemistry

The development of CRISPR molecular scissors allowed Frenchwoman Emmanuelle Charpentier and American Jennifer Doudna to win the Nobel Prize in Chemistry in 2020.

This technology has revolutionized genome processing through its accuracy and ease of use compared to previous tools.

Patients with sickle cell disease suffer from a mutation that affects hemoglobin, a protein found in red blood cells that transports oxygen to the body’s tissues. Because of this mutation, red blood cells become sickle-shaped, restricting blood flow and oxygen delivery.

This can lead to chronic anemia and extremely painful seizures. The repercussions, especially related to damage to vital organs, may be serious, and even fatal.

Both treatments, Casgevy and Lyfgenia, are now approved by the US Food and Drug Administration for patients aged 12 years and older.

US President Joe Biden praised these licenses as a “major achievement.” “This important medical advance is very promising for the development of other treatments,” he said in a statement.

“new era”

Casgevy, developed by Vertex Pharmaceuticals, was approved in November by British health authorities, but this new authorization is the first of its kind in the United States.

The patient’s cells are modified using Crispr technology and then transplanted back into the individual. During a clinical trial, 29 out of 31 patients did not suffer from a vaso-occlusive crisis for at least 12 consecutive months during a 24-month follow-up period.

The most common side effects were mouth pain, nausea, abdominal pain, and vomiting.

The second treatment, called Lyfgenia and developed by Bluebird Bio, works differently, as it uses a harmless virus to perform genetic modification.

Nicole Verdun, director of therapeutic products at the US Food and Drug Administration, said that two patients died from leukemia during clinical trials of this treatment, so a warning was added to the approved treatment to “inform the public” of the risks.

Verdun explained that an agreement was reached with the pharmaceutical laboratories to conduct follow-up studies for a period of 15 years.

For both treatments, once a patient’s stem cells are collected, they must undergo chemotherapy that aims to remove the cells from the spinal cord, allowing them to then be replaced with the modified cells.

Vertex Pharmaceuticals said in a statement that after the injection, with a single dose, patients will have to be followed for several weeks in the hospital. The company estimates that about 16,000 patients will be eligible.

According to Peter Marks of the US Food and Drug Administration, these treatments will be more suitable for patients who suffer from frequent and severe attacks, or “about 20%” of those infected with this disease in the country.

But according to Marks, the licensing of these two “potentially transformative” treatments demonstrates the current dynamism of this “promising new era of medicine.”