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by MARILYNN MARCHIONE, AP Chief Medical Editor
DOSSIER – In this photo of Monday, November 13, 2017, Brian Madeux begins to receive the first gene treatment treatment of Hunter gene, while his girlfriend, Marcie Humphrey, left, applauds UCSF Benioff Children's Hospital in Oakland, California Right Jacqueline Madden, Nurse Practitioner. On Thursday, February 7, 2019, scientists reported on the first effort to modify genes, or permanently modify the DNA, of a dozen adults, including Madeux, affected metabolic diseases. (Photo AP / Eric Risberg)
Scientists believe that they have made the first gene montage in the body, modifying the DNA in the adult to try to treat a disease, although it is too early to know if it will help.
Preliminary results suggest that two men with a rare disease now have a patching gene at very low levels, which might not be enough to make the therapy a success.
Nevertheless, it is a scientific milestone towards the day-to-day focus of DNA to treat many diseases caused by faulty genes.
"It's a first step," said Dr. Joseph Muenzer of the University of North Carolina at Chapel Hill, who participated in the treatment test. "It's not powerful enough."
He gave the results Thursday at a conference in Orlando, Fla., And consulted with the maker of the therapy, Sangamo Therapeutics, California. The researchers are working on a stronger version of the treatment.
Gene editing is designed as a more accurate way of doing gene therapy, disabling a bad gene, or providing a good one that is missing. It is not controversial to try to treat diseases in the adult and DNA changes are not pbaded on to future generations, unlike the recent case of a scientist Chinese who claims to have changed the binoculars genes when they were embryos.
Sangamo's studies involve men with Hunter or Hurler syndrome, diseases caused by a missing gene that makes an enzyme that breaks down certain sugar compounds. Without it, sugars accumulate and damage organs, often killing teenage people.
In 2017, Brian Madeux of Arizona became the first person to try it. During an IV, he received many copies of a fixative gene and an editing tool called zinc finger nucleases to insert into his DNA.
The findings on him and seven other Hunter patients, plus three with Hurler syndrome, suggest that the treatment is safe, which was the primary goal of these early experiments. Three problems – bronchitis, irregular heartbeat and hernia – were judged due to illness, not treatment.
Tissue samples showed very little evidence of genetic modification in two Hunter patients who received an average dose but not in a low dose patient. Tests are expected later this year on the highest dose patients and Hurler patients.
Blood tests have detected slightly higher levels of the missing enzyme in some of Hunter's patients, but none of them has reached a normal level. One patient showed a larger increase, but also showed signs that his immune system could attack the treatment. He was treated for this and the symptoms disappeared.
More encouraging results were observed in Hurler patients: enzyme levels returned to normal after treatment, as well as tests on certain blood cells.
"This is very promising" for patients with Hurler's disease, said Dr. Paul Harmatz of the UCSF Benioff Children's Hospital in Oakland, who presented these results.
None of the patients with one or the other of these diseases has presented lasting lowering rates of worrying compounds of sugar in the urine, and some other tests do not occur. also failed to detect the desired effects of the treatment.
The key test will be to stop weekly enzymatic treatments for patients to see if their body can now produce enough on its own. So far, three of them have interrupted their treatments and one of them has recently been advised to resume them due to fatigue and rising rates of compounds. sugar. The others did not leave long enough to know how they will get out of it.
"It looks like it's safe … it's a very positive sign," said an independent expert, Dr. Kiran Musunuru of the University of Pennsylvania. He described the preliminary results as promising, but said it was difficult to ensure that everything would be fine until patients were studied longer.
"What they're trying to do with gene editing is very difficult," he said. "It is much more difficult to make a correction or insert a gene" than to disable one.
Dr. Tyler Reimschisel of Vanderbilt University accepted.
"It's not discouraging, it's just early and on a small number of people," he said. "This is an innovative and innovative treatment", but it is unclear if this will help.
Dr. Sandy Macrae, president of Sangamo, said that a more powerful version was being manufactured. As the treatment appears safe, regulators have recently agreed to allow teens with Hunter syndrome to participate in the study. The ultimate goal is to treat young children before the disease causes a lot of damage. He added that the company will expect more results from current patients before deciding what to do.
"We have accomplished something important" by doing gene editing, he said. "There is a base on which to build."
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This Associated Press series was produced in partnership with the Howard Hughes Medical Institute's Department of Scientific Education. The AP is solely responsible for all content.
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