First Gene-Editing Treatment Approved by FDA in the US

Great news for those suffering from sickle cell disease! The United States Food and Drug Administration (FDA) has approved a groundbreaking new treatment. Casgevy is the first medicine based on CRISPR gene-editing technology, marking a huge leap forward in the battle against this life-threatening condition. 

[Related: The UK becomes the first country to approve CRISPR treatment.]

“Sickle cell disease is a rare, debilitating and life-threatening blood disorder with significant unmet need, and we are excited to advance the field especially for individuals whose lives have been severely disrupted by the disease by approving two cell-based gene therapies today,” said Doctor Nicole Verdun, director of the Office of Therapeutic Products within the FDA’s Center for Biologics Evaluation and Research. “Gene therapy holds the promise of delivering more targeted and effective treatments, especially for individuals with rare diseases where the current treatment options are limited.”

The life-long genetic condition is caused by errors in the genes for the protein hemoglobin. Red blood cells use hemoglobin to carry oxygen through the body. The abnormal hemoglobin makes the blood cells crescent-shaped and hard. The misshapen cells then clump together and block the flow of oxygen to the organs, which causes extreme pain. The cells can then die off early, which leads to anemia.

Sickle cell disease is particularly common among people with Caribbean or African ancestry and affects more than 100,000 Americans. Previously, the only known cure for sickle cell disease was a bone marrow transplant from a donor. These procedures come with the risk of rejection by the patient’s immune system and finding a matching donor is a difficult process. 

How Casgevy works

Casgevy uses CRISPR-Cas9 gene editing technique, allowing alterations to human DNA. French microbiologist, geneticist, and biochemist Emmanuelle Charpentier and American biochemist Jennifer A. Doudna shared the 2020 Nobel Prize in Chemistry for their work developing the technique.

The procedure uses stem cells taken from a patient’s bone marrow. The cells are brought into a lab and the genes that are meant to switch on a functioning version of hemoglobin are edited with CRISPR. Patients must then go through a “conditioning treatment.” This can involve taking a drug that suppresses the immune system, radiotherapy, or chemotherapy to get the body ready for an infusion of CRISPR-modified cells back into the body. The new treatment does not come with the risk of graft versus host disease the way that a traditional bone marrow transplant does.

The FDA has approved the treatment after a clinical trial with 45 patients. Of these, 29 patients have been in the trial long enough for the researchers to gauge how effective Casgevy is. For at least 12 months after treatment, 28 were free of severe pain caused by the disease.

[Related: These organisms have a natural gene-editing system that could be more useful than CRISPR.]

How Lyfgenia works

The FDA also approved another sickle cell treatment called Lyfgenia.

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