Indian scientists have developed a novel gene therapy to treat severe haemophilia A. The therapy, which has been published in the prestigious New England Journal of Medicine (NEJM), promises a potential one-time cure for a condition that currently requires lifelong management.
Haemophilia A
- Haemophilia A is an inherited disorder caused by a deficiency of a clotting protein called Factor VIII.
- It leads to severe, spontaneous, and potentially life-threatening bleeding episodes.
Severity of the condition
- Severe haemophilia A: when clotting factor is <1%.
- Statistics in India: Estimated 40,000-1,00,000 patients, second highest in the world
Types of Haemophilia
Congenital Haemophilia
- Haemophilia A: Factor VIII deficiency.
- Haemophilia B: Factor IX deficiency.
- Acquired Haemophilia: Occurs when the immune system attacks Factor VIII or IX.
Inheritance
- This disorder is usually caused by a defective gene on the X chromosome.
- Males are more affected, as they inherit only one X chromosome from the mother.
- Factor VIII: Role and Effect of Deficiency
- Factor VIII helps in blood clotting.
- Its deficiency causes prolonged bleeding and inability to form clots.
Clot Formation Process
- Platelets form a plug at the damaged blood vessel.
- Clotting factors, especially Factor VIII, form a fibrin mesh that stabilizes the plug.
Indian Gene Therapy: A New Hope
Mechanism
- A functional gene is inserted into the patient’s body.
- This gene produces Factor VIII, which is capable of stopping bleeding.
- Results: No bleeding was observed in the trials.
Significance
- It is safer than conventional adenovirus-based methods.• Likely to be suitable for children.
- Roctavian: World’s first gene therapy
- Roctavian is the first gene therapy approved by the US FDA (2023) to treat severe hemophilia A.
- It addresses the genetic cause of the condition and provides a one-time cure.
Mechanism
- A functional copy of the Factor VIII gene is delivered to the patient’s liver cells using an adeno-associated virus (AAV).
- The liver now produces adequate amounts of Factor VIII.
Importance
- Reduces or eliminates the need for routine clotting factor injections.
- Demonstrates high efficacy rates.