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A California toddler is the first person in the world to receive gene therapy to treat his devastating disease.
Three-year-old Oliver Chu was born with a rare, genetic condition called Hunter syndrome.
Also known as mucopolysaccharidosis type II (MPS II), Hunter syndrome is a disorder where the body cannot break down specific sugar molecules.
As these molecules accumulate in organs and tissues, they can cause progressive damage that affects the child’s physical and mental development.
Researchers at the University of Manchester in the UK have spent more than 15 years developing a gene therapy for Hunter syndrome.
Now, a team at Royal Manchester Children’s Hospital has seemingly stalled the disease by altering Oliver’s cells.
Oliver is the first of five boys in the world to receive the experimental intervention, and a year after beginning treatment, he appears to be developing normally.
“Every time we talk about it, I want to cry because it’s just so amazing,” his mother, Jingru Chu, told the BBC.
Almost always exclusive to boys, Hunter syndrome affects 1 in 100,000 male births worldwide.
Patients seem healthy at birth, but they begin to show symptoms around the age of 2.
A genetic error prevents cells from producing the enzyme iduronate-2-sulfatase (IDS), which is essential for breaking down large sugar molecules.
In the most severe cases, children start to experience problems with basic functioning between 6 and 8.
Patients with the severe form of the disease typically die in their late teens or early 20s.
Oliver’s treatment began last December when the team harvested stem cells from his blood. Scientists then inserted the missing IDS gene into a hollow virus shell designed to deliver it into the stem cells’ nucleus.
“We use the machinery from the virus to insert a working copy of the faulty gene into each of the stem cells,” Dr. Karen Buckland, lead scientist for Great Ormond Street Hospital’s Cell and Gene Therapy Service, explained to the BBC.
“When those go back to Oliver, they should repopulate his bone marrow and start to produce new white blood cells, and each of these will hopefully start to produce the missing protein [enzyme] in his body.”
As planned, these genetically engineered stem cells were delivered via infusion in February to repopulate Oliver’s bone marrow. The team was hopeful that the stem cells would begin producing white blood cells, which would then make the missing enzyme and deliver it throughout his body.
Follow-up tests in May revealed that the gene therapy was working, and Oliver was indeed producing the key enzyme.
“He’s doing really well. We have seen him progressing in his speech and mobility. In just three months, he has matured,” his father, Ricky, told the BBC.
Ricky and Jingru reported that Oliver is “so different” from before his treatment — now he is more verbal and engaged with other children.
“I’ve been waiting 20 years to see a boy like Ollie doing as well as he is, and it’s just so exciting,” said Simon Jones, who is co-leading the trial.
“Before the transplant, Ollie didn’t make any enzyme at all, and now he’s making hundreds of times the normal amount. But more importantly, we can see he’s improving, he’s learning, he’s got new words and new skills, and he’s moving around much more easily.”
Until now, the only medical treatment available for Hunter syndrome was Elaprase. The drug, which costs around $600,000 per patient per year, can slow the physical effects of the disease, but because it cannot cross the blood-brain barrier, it cannot stave off cognitive decline.
Oliver was initially deemed too old for the trial, as the treatment cannot reverse existing damage. However, tests revealed that his development was largely unaffected.
He, along with the four other boys who received the treatment, will be monitored for two years. The research team is hopeful that, if the trial is deemed successful, they can partner with a biotech firm to license the treatment.
“We need to be careful and not get carried away in the excitement of all this, but things are as good as they could be at this point in time,” said Jones.
