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A new gene therapy treatment developed in the United States has been tested in a trial on 10 young children born without a functioning immune system. Several months later, the young subjects would all be doing “incredibly well”.
It’s a great story that was published 3 days before Christmas by the New England Journal of Medicine, of those who believe in science. Ten young children aged 18 months to 4.5 years, born without a functioning immune system, and unable to fight infections, are living normal lives, thanks to a new gene therapy treatment developed in San Francisco.
Modify children’s own genes to avoid complications
These ten children have Artemis-SCID. According to the rare diseases site Orphanet, it is a severe combined immune deficiency characterized by serious and recurrent infections, diarrhoea, failure to thrive and excessive cellular sensitivity to ionizing radiation.
The very rare genetic condition is usually treated with a bone marrow transplant from a healthy donor. The new gene therapy allows researchers to treat newly diagnosed babies with their own cells – adding a healthy copy of the Artemis gene to marrow stem cells harvested from the baby, then infusing the corrected stem cells into their bodies in hopes of avoid many short- and long-term complications of standard treatment, including death.
A complete success for the 10 children treated
The first outcome of the trial involved the safe transfusion of genetically corrected cells that would differentiate into white blood cells 42 days after infusion. The second outcome was T cell reconstitution at 12 months, a measure of the strength of the immune system.
All 10 patients were safely transfused with their own genetically corrected stem cells, which gave rise to corrected peripheral blood cells within 42 days.
- All 10 were developing their own T cells and B cells at 12 weeks;
- Four out of nine achieved complete T-cell immune reconstitution at 12 months;
- Four out of nine also achieved full B-cell immunity at 24 months, allowing them to stop immunoglobulin replacement and receive standard childhood vaccinations;
- Three other patients, who were followed for less than 24 months, showed promising B cell development compared to previous results for donor transplant patients;
- One child needed a second infusion of gene-corrected bone marrow due but is now free of infection with good T and B cell immunity.
Spectacular results
A result described as spectacular by Jennifer Puck, co-principal investigator of the study.
“All results are better than those previously seen with Artemis-SCID patients who received donor bone marrow transplants. The fact that the patients in the trial achieve complete immunity against T cells is exceptional. B-cell recovery takes longer, but so far it appears patients also have a much better chance of B-cell recovery than they would with a bone marrow transplant.”
Genetic correction has already been used in patients with other genetic forms of SCID, but its use is crucial here, because these young patients, detected at birth, generally respond less well to standard bone marrow transplants. In their case, a transplant can lead to rejection, graft versus host disease, chronic infections leading to organ damage, growth retardation and even premature death. With this gene therapy, on the other hand, these children can hope to lead a normal life. Witness Laverna Shorty, the grandmother of the first child to enroll in the clinical trial as an infant in 2018,
“Today he is no longer sick. He threw away all his medication. He is happy and he is becoming a young man”.