In a revolutionary way, a group of doctors managed to remit an incurable cancer suffered by a girl of 14 years.
All the treatments had failed to save the life of Alyssa, who suffers from leukemia, for this reason the doctors made the decision to apply a new therapy.
The Doctors at the Great Ormond Street Hospital, located in London, United Kingdom, used a technique called “base editing”, in order to create, thanks to biological engineering, a new “living drug”.
Six months After starting the treatment, the has managed to remit the disease, which is now undetectable in Alyssa’s body, although the girl continues under medical evaluation in case the cancer comes back.
Alyssa, who has years old and lives in the city of Leicester, was diagnosed with acute lymphoblastic leukemia in May of 257.
As is known, T cells are in the body to guard against possible diseases, but in Alyssa’s case, these cells had become a threat and they were growing out of control.
Her cancer was very aggressive. Chemotherapy and even a bone marrow transplant had not worked as a treatment.
If the decision to resort to the innovative treatment had not been made, the only course for Alyssa was to try to have a life as comfortable as possible, but without much hope of survival.
“Eventually I would have passed away”, Kiona, Alyssa’s mother, told the BBC.
Unthinkable a couple of years ago
“At the end of last year we thought it was going to be the last Christmas we were going to be with her. And well, in January, when he turned 14 years, all I did was cry”, he added.
The remission of Alyssa’s cancer would have been unthinkable a couple of years ago and it was possible thanks to the incredible advances in the field of genetics that have been achieved recently.
The The team at Great Ormond Street Hospital used a technology known as ‘base editing’, which was invented just six years ago.
The bases nitrogenous or nucleotides are the language of life.
The four types of bases -adenine (A), cytosine (C), guanine (G) and thymine (T)- are the bricks with which our genetic code is built.
As well as the letters make up words that have meaning, the billions of bases in our DNA build the instruction manual for our body.
What base editing allows scientists to do is focus on a precise part of this genetic code, alter the molecular structure of a single base, converting it to a different one and thus changing the genetic instructions.
A complex process
What the doctors who treated Alyssa’s case did was use this tool to design or edit a new T cell that was able to hunt down and kill the cancer cells that were killing it.
It was a complex process, involving several steps that started with a few healthy T cells that were donated by a person.
Later, editions were made in three databases that consisted of the following:
• The first base edit disabled the T-cell mechanism from attacking Alys’s body sa.
• The second edition removed a chemical mark, called CD7, which is found on all T cells, in order to protect the cells that were donated.
• The third edition was an invisibility cloak in order to make them resistant to chemotherapy drugs.
And the final stage of this genetic modification was to instruct the T-cells to hunt down any trait with the CD7 chemical mark, including cancer cells, once they entered Alyssa’s body.
That was the reason why the CD7 mark was removed from the therapy in the second base edition, otherwise the donated cells would be would have destroyed themselves.
If the therapy worked, Alyssa’s immune system, including T-cells, would recovered with a second bone marrow transplant.
When the process was explained to the family, Kiona asked, “Do you guys can they do that?”
“She is the first patient treated with this technology“, Professor Waseem Qasim from Great Ormond Hospital explained to the BBC. Street.
He said that this genetic manipulation was a “area of science that is advancing very fast and with enormous potential to treat many diseases” .
However, it was not a bed of roses: Alyssa was left very vulnerable to infection, since the modified cells attacked so much the cancerous T cells in her body as well as those that protect it from diseases.
But the truth is that a month later, Alyssa was in remission.
There she received a second bone marrow transplant to regenerate her immune system.
It was a long process: she had to go through 14 weeks in the hospital and could not see his brother , who was still going to school and could carry several germs.
An “incredible opportunity”
In addition, in the review that was carried out three months after the therapy, signs of cancer were found again.
But the last two analyzes have not shown traces of the disease.
” You just learn to appreciate every little thing. I’m so grateful to be here now,” Alyssa explained.
“It’s crazy. It is amazing that he was able to have this opportunity, I am very grateful for it and it will also help other children in the future”, she added.
Now she is thinking about Christmas, being a bridesmaid at her aunt’s wedding, riding her bike, going back to school and “just doing normal people things”.
Of course, the family hopes that the cancer never returns, but they are already grateful for the new time that the treatment has given them.
“Having this extra year, these last three months when he has been home, has been a gift in itself myself,” Kiona recounted.
“It’s pretty hard for me to talk about how proud we are. When you see what she has been through and the vitality of life that she has brought to each situation, it is exceptional”, explained James, Alyssa’s father.
Although most children with leukemia respond to traditional treatments, it is estimated that up to a dozen children a year could benefit from this therapy.
Alyssa is only the first of ten people to be administered this ” live drug” as part of a clinical trial.
Robert Chiesa, a doctor in the department of bone marrow transplantation at the Great Ormond Street Hospital, is clear about the benefits.
“It is extremely exciting. Obviously, this is a new field in medicine and it’s fascinating that we can redirect the immune system to fight cancer,” he told the BBC.
However, technology only scratches the surface surface of what base editing could achieve.
For the specialist David Liu, one of the inventors of the basic edition at the Broad Institute, it is “a bit surreal” that people were being treated just six years after the technology was invented.
And the doctor Liu is surprised by the complexity of the process.
For example, in the therapy that was applied to Alyssa, each of the edits involved break a section of the genetic code so that it basically stopped working.
But there are less complex applications where, instead of disabling a feature, a faulty one can be fixed.
Sickle cell anemia, for example, is caused by a change in one of these bases that could be corrected with this revolutionary technique.
Therefore, there are already ongoing base-editing trials in sickle cell anemia, as well as high cholesterol that runs in many families.
“Therapeutic applications of base editing are just beginning and it is humbling to be a part of this era as science was now taking key steps to take the control of our genomes,” Liu concluded.
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