An on-going clinical trial suggests that gene therapy is effective in stopping the progression of Cerebral Adrenoleukodystrophy
Cerebral Adrenoleukodystrophy (CALD) is a severe and potentially fatal form of a rare genetic disorder called Adrenoleukodystrophy (also known as Lorenzo’s Oil disease). It mostly affects young males, and is caused by a defect in a gene called “ABCD1”. This mutation results in abnormal breakdown of very-long-chain fatty acids. The fatty acid build up causes damage to the sheath that surrounds nerve cells in the brain (this is called the myelin sheath). Symptoms include losing the ability to walk and talk. Currently, the only available treatment is bone-marrow transplantation.
Now, an on-going clinical trial suggests that gene therapy can stop the progression of CALD. The initial results of the Phase 2-3 trial was published today in the New England Journal of Medicine.
This therapy involves taking stem cells from the patients, and then using a viral vector to insert the correct version of ABCD1 into the cells in the lab. Then, the modified stem cells are returned back into the patient.
The study, published in the New England Journal of Medicine, followed 17 boys between 4-13 years old for two years. At the two year mark, 15 of the 17 patients were alive and free of major disabilities.
Of the other two patients, one withdrew from the study (and later died from complications of bone-marrow transplant). In the other patient the disease progressed rapidly and he died 22 months after the infusion of the modified stem cells. The researchers noted that the cause of death was not directly related to the gene therapy.
Therefore, these early results suggest that the gene therapy is safe and effective. The trial is ongoing and has received regulatory approval to expand patient numbers. It is led by Bluebird Bio and is currently recruiting across the USA (Los Angeles, Boston, Minneapolis), in France, and in the UK.
Link to the published study: http://www.nejm.org/doi/full/10.1056/NEJMoa1700554?query=featured_home
Link to the clinical trial (“the STARBEAM study”): https://clinicaltrials.gov/show/NCT01896102