Washington (AFP)
Last summer in Nashville, an American mother had her genome modified and stopped suffering.
"Since I was 11, I had hoped for a cure," wrote Victoria Gray, 34, at AFP. "Since I received the new cells, I have found the pleasure of spending time with family without living in fear of pain or an emergency."
Victoria has a genetic disease of the blood, sickle cell disease, which causes excruciating attacks. She participated in an experimental treatment. Over several weeks, his blood was taken from him, before extracting the cells that cause his illness: the stem cells that lodge in the bone marrow and make red blood cells - cells that are deformed in Victoria, causing seizures.
These stem cells were shipped to a Scottish laboratory, where their DNA was modified using a new tool called Crispr / Cas9 (pronounced "crisper"), and dubbed molecular scissors. Then, he was retransfused the genetically modified cells ... which returned to the fold, in the bone marrow. "Miracle," said Victoria: after a month, it produced normal blood cells.
It is unknown if the repair will last. But in theory, she is healed for life.
"It's just one patient, it's still early," says her doctor, Haydar Frangoul, of the Sarah Cannon cancer center in Nashville. "But these results are great."
In Germany, a 19-year-old woman was treated with the same method for another blood disorder, beta thalassemia. She previously needed 16 annual blood transfusions. Nine months later, she was released.
Living DNA has been modified for decades, as corn or GMO salmon testify. Including for humans in therapeutic trials for these and other blood diseases with older techniques.
But Crispr, invented in 2012, has democratized the practice because it is simpler than previous technologies, cheaper, and usable in small laboratories. And it is because it is easy to use that it has revived the fantasies about the manipulation of the living.
"Everything is going very fast," said AFC co-discoverer Crispr, French geneticist Emmanuelle Charpentier, co-founder of Crispr Therapeutics, the company that is carrying out this first clinical trial.
- 2019, year of breakthroughs -
Crispr is a revolution, but still experimental.
It should not hide that the year 2019 marked a historic turning point in an adventure started three decades ago: gene therapy becomes a reality.
For the first time, gene therapies have obtained the green light for marketing for a neuromuscular disease which condemned babies to early death (in the United States) and for a blood disease (in the European Union). In total, there are now eight gene therapies placed on the market worldwide, the majority against cancers and in particular one against a form of blindness.
Gene therapy involves inserting a normal gene into cells that have a faulty gene, such as a Trojan horse, so that it does the job that the bad gene does not: make normal red blood cells, for example, or in in the case of cancer, make white super-cells that kill tumors.
Crispr goes further. Instead of adding a new gene to cells, the tool modifies the existing faulty gene.
The French may remember the first Telethon, in December 1987, for the benefit of children with myopathies, muscular diseases. Seven of the eight gene drugs authorized today, after years of clinical trials, are directly or indirectly linked to research launched by the Telethon and its laboratory, the Genethon.
In Paris, Serge Braun, the scientific director of the Telethon, whose 33rd edition has just taken place, sees 2019 as a pivotal year, a prelude to a medical revolution.
"Twenty-five, thirty years is the time," he told AFP. "It always takes a generation, gene therapy has not escaped it. Now, it is going to crescendo".
Near Washington, within the American Institutes of Health, a "breakthrough period" is also celebrated.
"We have reached an inflection point," said general secretary Carrie Wolinetz.
The problem is that these new therapies are overpriced: up to one or even two million dollars, forcing painful negotiations with insurers. They also require heavy technique, so are restricted to rich countries.
Victoria Gray thus spent months in hospital, between blood tests, chemotherapy to clean the bone marrow, the transplant by infusion, and a final hospitalization of a month ... Without counting a sepsis, an infection.
"We can't do that in the local hospital," points out his doctor.
Still, the number of authorized gene therapies will increase to forty by 2022, according to MIT researchers, for cancers and diseases of the muscles, nervous system, eye ... China, in particular, has many trials in progress.
- sorcerer's apprentices -
The simplicity of Crispr has spurred the imagination of sorcerer's apprentices.
In China last year, a scientist, He Jiankui, modified embryos during in vitro fertilization with Crispr, which became the twins Lulu and Nana, causing him to be ostracized by the international scientific community.
He wanted to create an immunizing mutation against the AIDS virus (without apparent necessity), but caused other mutations inadvertently ... which will be transmissible to their descendants.
"The technology is not yet secure," says Kiran Musunuru, professor of genetics at the University of Pennsylvania. Crispr scissors often cut next to the targeted gene. "It's easy to use if you don't care about the consequences."
But ethical self-discipline seems to prevail. Even if a Russian, Denis Rebrikov, plans to use Crispr to help deaf parents have children without disabilities.
For animals, the temptation is to modify the genome of whole species: malaria mosquitoes to decimate them (Burkina Faso); or the host mice of Lyme disease ticks (United States). Their designers are advancing cautiously, aware of the unpredictability of chain reactions on the ecosystem.
Emmanuelle Charpentier does not believe in the darkest predictions.
The American "biohackers" who inject Crispr bought on the internet? "Not everyone is a biologist or a scientist," she sweeps.
And a military hijacking to create soldier-killing viruses or bacteria that would ravage the enemy's agriculture? "I am a bacteriologist, we have been talking about bioterrorism for years," she philosophizes. "Nevertheless, it never happened."
She remains convinced that technology tends to be used for the best and that, in essence, the future will bring more Victoria than Lulu and Nana.
© 2019 AFP