FDA Approves Frist Gene Therapies for Sickle Cell Disease

In the last week’s press release, the U.S. Food and Drug Administration (FDA) has approved two groundbreaking gene therapies- Casgevy and Lyfgenia for sickle cell disease (SCD) treatment. These are the first cell-based gene therapies for people 12 and older with SCD. Casgevy is particularly notable because it's the first FDA-approved therapy using CRISPR/Cas9, a revolutionary gene editing technology.

This FDA's approval shines light on the extensive research by top pharmaceutical companies. One of them being Vertex Pharmaceuticals and CRISPR Therapeutics have got the approval for their CRISPR/Cas9 gene therapy named Casgevy, that treats SCD by editing patients' blood-forming stem cells to produce more fetal hemoglobin, preventing sickle-shaped red blood cells. CRISPR/Cas9 edits DNA precisely, targeting specific areas, to modify the stem cells which are later transplanted back into patients’ body which increasingly produces fetal hemoglobin to cut down the painful sickle cell episodes. Bluebird Bio Inc., is another company which got an approval for Lyfgenia, which uses a lentiviral vector to make genetic modifications, producing HbAT87Q, a type of hemoglobin that lowers the risk of sickling and blood blockages, possibly helping with painful episodes.

The approval of these therapies marks a significant milestone in SCD treatment, providing potential cures for patients when traditional treatments haven't worked. Both the therapies use patient's own blood stem cells, which are changed and given back to them in a one-time infusion during a blood stem cell transplant. But before the treatment, these stem cells undergo high-dose chemotherapy, which removes cells from the bone marrow to make space for the modified cells. Then, they're watched closely over time to see how effective and safe does the treatments work. Clinical trials have shown good results, with many patients having fewer painful sickle cell events after treatment.

While these therapies are the first-ever approved, there are challenges ahead with the treatment process being really tough, involving strong chemotherapy and a stem cell transplant. This can be difficult for some people to undergo, especially those who already face challenges due to sickle cell disease. And the cost is also an another concern, as it can be as high as $2 million per patient, making it unaffordable for the lower middle class people. Also, we're still not sure about how safe and effective these CRISPR therapies are over time. The FDA has instructed the companies to closely monitor patients for up to 15 years to identify any issues, such as changes in their DNA that may lead to other health concerns. Additionally, there's a specific black box warning for Lyfgenia regarding the risk of blood cancers.

The approval of Casgevy and Lyfgenia by the FDA is a greater in for gene therapy in medical innovations, offering hope to people with sickle cell disease and their families. Alike these many more CRISPR gene therapies are on the horizon for patients with other genetic disorders, promising new hope for those in need.

The article is authored by Laharika Katamoni, Scientist at BioCheck,Inc., California, USA.