Pioneering gene therapy in UK offers hope after three-year-old’s progress | Medical research
Doctors are cautiously optimistic about a pioneering gene therapy for children with a devastating genetic disorder after seeing positive results in the first boy to receive the treatment.
Three-year-old Oliver Chu from California became the first patient to receive the treatment nine months ago as part of a clinical trial conducted by researchers in Manchester. It is too early to call the treatment successful, but doctors are encouraged by the progress made so far.
Professor Simon Jones, a consultant in pediatric metabolic genetic diseases at the Manchester Center for Genomic Medicine (MCGM) at St Mary’s Hospital, said: “Things are looking really hopeful at the moment, but Ollie was the first human to receive this treatment and he was only nine months old.
“We have four other boys due to attend and we will need to prove that the benefit is long-term,” said Jones, joint chair of the trial.
Oliver was born with a condition called Hunter Syndrome. It is caused by a defective gene that prevents the body from producing an important enzyme that breaks down complex sugar molecules. Over time, these molecules accumulate in organs and tissues, causing a range of symptoms, from joint stiffness and hearing loss to heart problems and cognitive decline, similar to dementia. Life expectancy is usually 10 to 20 years.
The only medication licensed for children with Hunter syndrome is Elaprase, a weekly infusion that replaces the missing enzyme. The treatment costs around £375,000 per patient and must last a lifetime. While the drug can improve movement and organ problems, it does not reach the brain and therefore cannot prevent cognitive decline.
During a one-time treatment in February, doctors collected stem cells from Oliver’s blood and replaced the defective gene with a working version. The corrected stem cells were then reinjected back into the bloodstream. There, they began producing high levels of the enzyme, which also reached his brain.
Since receiving the treatment, Oliver no longer needs weekly Elaprase injections, an encouraging sign that the treatment is working. The trial is being run from Royal Manchester Children’s Hospital in collaboration with MCGM at St Mary’s.
Speaking to the BBC, Oliver’s father, Ricky, said: “I don’t want to jinx it, but I feel like things have gone very well.
He added: “His life is no longer dominated by needles and hospital visits. His speech, agility and cognitive development have improved dramatically.” “It’s not just a slow and gradual curve as he gets older, it’s gone up dramatically since the transplant.”
Oliver’s parents hope the treatment will also help his older brother Skyler, who suffers from the same condition. Treatment cannot reverse existing damage to organs and tissues, but tests on Skylar showed that despite being five years old, he was largely unaffected.
Hunter syndrome largely affects boys, but is extremely rare, affecting one in every 100,000 boys born globally. The five boys on trial are from the United States, Europe and Australia. None of them were from the UK because the patients were not diagnosed soon enough.
“To treat the majority of patients at this dose, we would need to screen newborns with the heel prick test, which is now standard for Hunter syndrome in the United States,” Jones said. The same gene therapy approach is now being developed to treat other genetic disorders that impair vital enzymes, such as Hurler syndrome and Sanfilippo syndrome.