In an twist of fate, a brand new gene therapy for the treatment of Adrenoleukodystrophy (ALD) uses one of medicine’s greatest nemesis, HIV, to treat this fatal genetic brain disease– and the results have been very encouraging.
ALD, which mainly attacks male patients, destroys the protective cover that protects the brain’s neurons. Currently around 14,000 people in the U.S. suffer from this devastating disease.
The pediatric form of ALD is usually diagnosed as symptoms become apparent. The average age of the patient upon diagnosis is approximately 7 years of age. The boys, who appear to be healthy and normal, start showing symptoms that may manifest themselves as behavioral issues. As the brain cells are destroyed, the patient’s ability to speak and walk are lost. After diagnosis, most patients die within 5 years.
A very small pilot study conducted in France was the first step in examining this novel new approach to combating ALD. First, researchers took stem cells from the bone marrow of patients. Then they inserted a good gene, using a disabled form of HIV, into the patient’s own cells. HIV does this with a higher safety margin than other viral carriers. Finally, they inserted the stem cells back into the patient’s bone marrow. In the study, the treatment halted the progression of the disease in two patients.
The new therapy did this this without the serious side effects that can accompany the current treatment of choice, which is a bone marrow transplant. Bone marrow transplants can be dangerous– approximately 20% of patients receiving this therapy die, and still others have serious disabilities for the rest of their lives.
The results of the French study brought about a larger more recent study published in The New England Journal of Medicine in October of last year. In this study, gene therapy was used to treat 17 male patients between the ages of 4 and 13. 15 of the boys are now living without the disease (2 years post-treatment).
The other two boys in this study died. The first boy had a course of ALD that progressed so rapidly that gene therapy could not stop the disease. The treatment has to be administered early to be successful; it takes about a year for the treatment to reach the brain cells and help insulate the neurons. The second boy was treated with bone marrow transplant and died from complications.