NEWS – Britain approves world’s first gene therapy Casgevy for sickle cell disease and thalassemia
By Vertex Pharmaceuticals (Europe) Ltd. and CRISPR Therapeutics.
How does Casgevy work?
- Edits a patient’s own blood stem cells to produce high levels of Fetal hemoglobin
*Fetal hemoglobin – healthy, oxygen-carrying form of hemoglobin + produced during fetal development + shuts down soon after birth
- Increase of Fetal hemoglobin reduces the mildness of Sickle cell disease improving the outcome
- Tech is based on CRISPR/Cas9 enzyme which makes a cut at a specific spot in a gene called BCL11A which disables a DNA brake on the production of fetal hemoglobin
- Cost effective
- Reduce the dependency on Bone Marrow
WHAT IS CRISPR?
- Way to change specific areas of DNA
- Learnt from bacteria, which use it as an immune system to fend off attacks by viruses
- A CRISPR editing system has two parts: a “guide RNA” sequence and a pair of molecular “scissors.” The guide sequence leads the scissors to a specific spot on the double helix and the scissors cut the strand of DNA there, inactivating that gene
WHAT IS SICKLE CELL DISEASE? WHAT IS BETA THALASSEMIA?
- Sickle Cell Disease (SCD):
- Cause: Mutation in the HBB gene, leading to the production of abnormal hemoglobin known as hemoglobin S (HbS).
- Effect: Cause red blood cells to become rigid and take on a characteristic “sickle” shape, which can lead to various complications, including pain, anemia, and organ damage.
- Beta Thalassemia:
- Cause: Mutations in the HBB gene that result in reduced or absent production of normal hemoglobin (beta-globin).
- Effect: The reduced or absent beta-globin leads to an imbalance in the production of alpha and beta chains, causing an excess of alpha chains that can damage red blood cells and lead to anemia