Medical researchers at the Christian Medical College, Vellore, have reported a significant advancement in the treatment of severe haemophilia A through gene therapy. Haemophilia A is a rare, hereditary condition caused by a faulty gene that leads to severe, spontaneous, and potentially fatal bleeding episodes.
What is the usual treatment?
The primary treatment for haemophilia is replacement therapy, which involves administering clotting factor concentrates to prevent bleeding. These concentrates can be derived from human blood or produced synthetically (recombinant clotting factors). However, challenges include the body's immune response potentially destroying the clotting factor before it can work, rendering the therapy ineffective.
What is gene therapy in haemophilia?
Gene therapy introduces a 'corrected' gene into the patient's cells to enable normal expression of the necessary clotting factor. The FDA-approved Roctavian therapy uses an adeno-associated virus (AAV) vector for this purpose, showing a decrease in annualized bleeding rates from 5.4 to 2.6 bleeds per year in treated patients.
How was the Vellore trial different?
The Vellore trial utilized a lentivirus vector instead of an adenovirus, addressing the issue of pre-existing antibodies against AAV in many patients. This approach integrates the gene into adult stem cells, promising a reliable, lifelong production of the clotting factor without side effects. In the trial, none of the five patients experienced bleeding episodes over an average follow-up period of 14 months.
This breakthrough represents a significant step forward in the treatment of haemophilia A, offering hope for a more effective and lasting solution to those affected by this challenging condition.
