Researchers from the neuromuscular diseases unit of the Sant Joan de Déu hospital, in Barcelona, have applied, for the first time in a child under 4 years of age, a gene therapy for the treatment of Duchenne dystrophy, the most common muscular dystrophy diagnosed during childhood.
The pioneering treatment has been carried out within the framework of an international, active and open clinical trial for this type of patient, in which six centers from different countries participate. The Sant Joan de Déu team has been the first to include a patient under 4 years old.
The hospital is confident that being the first to activate the study will allow it to offer the opportunity to access this treatment to a greater number of children. Gene therapy, and applied as soon as possible, is the most promising therapeutic option to stop Duchenne dystrophy, of genetic origin.
Until now, only those older than 4 years had been treated, with positive results thanks to which the therapy has been approved by the US Drug Agency (FDA) for patients aged 4 to 5 years.
Sant Joan de Déu is studying other cases susceptible to receiving the therapy due to the result of the first experience, which took place several weeks ago. “The patient has remained stable, without side effects and we are waiting to confirm the positive results in his evolution,” explained the head of neuromuscular diseases at the hospital, Andrés Nascimento. “We have good expectations, since the changes that this gene therapy can generate occur on more preserved muscle tissue,” he continued.
Cataloged as a minority disease, with about 20,000 new cases a year in the world, Duchenne dystrophy progressively weakens the muscles, a deterioration that becomes evident around the age of 3 or 4 years and worsens until at 12- 14 the ability to walk may be lost.
The only treatments currently available only aim to stabilize the progression, not to cure or improve symptoms, making the appearance of gene therapy an important advance.
One of the challenges of this therapy was the size of the gene that codes for dystrophin (a mutation in this gene is the cause of the disease), which is very large and cannot be introduced through the viral vectors that are responsible for transporting the new gene to the cells so that it attaches to them.
A few years ago, alterations in the dystrophin gene were observed in adult individuals that gave rise to smaller versions of the protein known as microdystrophins. Scientists then began to explore the possibility of using microdystrophin in patients with Duchenne dystrophy.
Clinical trials have been carried out in children aged 4 to 8 years. A few weeks ago, the trial began in children aged 3 to 4 years, which will include ten patients in the first stage, and depending on the safety results, children under 3 years of age will be allowed to participate.
In addition to the Catalan hospital, centers in the United Kingdom, the Netherlands, France and Belgium are participating in the research. San Joan de Déu hopes to be able to include at least four other patients between 3 and 4 years old. One of the requirements to receive the treatment is that patients must not have antibodies against the vector (modified adenovirus) that carries the dystrophin microgene.
