Source: TH
Context: Researchers has achieved a milestone by conducting a successful gene therapy trial for severe haemophilia A using a lentivirus vector.
Gene Therapy for Haemophilia A:
What is Haemophilia A?
- Definition: A hereditary bleeding disorder caused by the deficiency of clotting Factor VIII.
- Genetic Cause: It arises due to a defective gene on the X chromosome.
- Prevalence: More common in males; females are typically carriers.
Symptoms
- Prolonged Bleeding: Following injury or surgery.
- Spontaneous Bleeding: Internal bleeding in joints and muscles without apparent cause.
- Bruising: Unusual or frequent bruises.
- Hemarthrosis: Bleeding into joints, causing pain and swelling.
What is Replacement Therapy?
- Definition: A standard treatment where clotting factors are injected into the veins to replace the deficient Factor VIII.
- Mechanism: Derived from human plasma or produced synthetically (recombinant clotting factors).
- Challenges:
- Short lifespan of clotting factors in the body.
- Antibodies may neutralize the clotting factors, reducing effectiveness.
What is Roctavian?
- Definition: The first FDA-approved gene therapy for severe haemophilia A.
- How It Works:
- Uses an adeno-associated virus (AAV) vector to deliver a corrected gene encoding Factor VIII.
- The gene integrates into liver cells to produce clotting Factor VIII.
- Efficacy: Reduces annual bleeding rates but requires corticosteroids to suppress immune reactions.
- Limitations: Treatment response may wane over time, and pre-existing antibodies to AAV may limit its use.
Lentivirus Vector in Gene Therapy:
- Advantages:
- Rarely triggers pre-existing
- Integrates into host cells, ensuring long-term production of clotting factors.
- Indian Approach: Gene transfer into adult stem cells for lifelong efficacy.
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