The first trials of gene therapy are brought to bear in a rare disease, myopathy myotubulaire
This genetic disease affects the sexual chromosome X in a boy about 50,000 in France and 50% of children who die before their 18 months. This alteration affects, more accurately, the gene that encodes the protein responsible for the proper functioning muscle. Because of this, people are experiencing severe respiratory failure and extreme muscle weakness.
These first tests were done on “a cohort of 4 boys. 3 received the treatment in the form of a single injection, the fourth child, who is used as a reference comparative will receive it later for the sake of ethics.
They have 9 months, 4 years, 2 years and a half and 4 years old. In the case of the former, only 12 weeks after injection, improvements in mobility, strength, and respiratory capacity were observed. Now he can sit and hold its head, which was not the case prior to the treatment. These parameters are close already to normal.
The other two children received the injections, there are 8 and 4 weeks, there is also rapid progress,” says Serge Braun, scientific director AFMtelethon. This protocol must be repeated in the weeks on two other cohorts of four children. Gene therapy with a virus genetically modified To introduce the gene medicine, researchers used a virus dubbed AAV8. “It belongs to a family of viruses that generate no known disease. Nevertheless, it is genetically modified so that it is unable to reproduce. The gene drug that allows the cells to produce the enzyme is inserted into the virus,” says Serge Braun.
Injected into the blood, this virus is able to distribute in the muscles . Once arrived, it will lead to the production of the missing enzyme by the muscle fibers. The patient will be able to find a musculature almost normal.
“This is the first time in the world where something is injected to this disease, the main criterion is obviously the security. In fact, the product administered is composed of a large amount of virus is genetically modified. But this injection produced in these children a kind of response to vaccine against this virus which will prevent any reintroduction,” says the scientific director.
Because of this, they have so far received the minimum dose but still sufficient to obtain therapeutic results. The doses will be increased gradually in the next two cohorts. Healed to life?”In the case of this disease, it is known that when the virus enters the muscle, it stays there for a very long time, or even life,” he explains. But in this case, it is children, and with growth, their muscles will grow and there may be a dilution: more muscles, but with a constant number of viruses. “But normally, the quantity of virus injected at the start should be sufficient and should continue to be effective in life,” says Serge Braun.
“In the short term, we cannot exclude secondary effects linked to the virus injected.
Inflammation of the liver can eventually be identified, but they are reversible by taking transient cortisone”.
Thanks to the telethon Prior to these tests, it was necessary to find the gene responsible for the disease, which has been possible thanks to a team of researchers from Strasbourg.
He then had to understand how it worked, and imagine the treatment. “This is where it is the result of a French research, led by Ana Buj Bello within our laboratory Généthon. All this has been funded through the Telethon.
The trial is now international, in collaboration with a biotech american and european children are provided in the next steps of the study,” says Serge Braun. If the results prove to be really encouraging, a study involving more patients could be performed to confirm the reality of statistics of the treatment effect. “If the results remain as spectacular, one can expect to earn time on the necessary formalities for a maximum of patients access treatment more quickly. And in any case, they will all be monitored for life,” says Serge Braun. All of this was to find the right virus and produce it in sufficient quantity.
“It is both an advanced science and technology to be able to understand the mechanisms and to be able to implement on a large scale. We have rarely attended to the realization of hopes is also important. We must remain cautious but we are very excited,” he says.