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According to an announcement from Inserm, the work undertaken to find a vaccine against allergic asthma has taken a new step and should lead to a clinical trial soon. If confirmed, such a vaccine would bring relief to millions.
Allergic asthma is a symptom that affects, more or less seriously, 4 million people in France and 340 million worldwide. But faced with this scourge, only specific treatments can relieve the allergic person. This is why scientists from Inserm, CNRS and Toulouse III-Paul Sabatier University are currently developing a new vaccine.
A latest study published on March 7 looks promising: their vaccine would be effective in producing antibodies capable of neutralizing key human immune proteins in the triggering of allergic asthma. Their results pave the way for the organization of a clinical trial on humans.
As the researchers explain, exposure to house dust mites and other allergens triggers an overproduction of antibodies called immunoglobulin E (IgE) and proteins called “type 2 cytokines” (interleukins IL-4 and IL-13) in the human pathways. aerial.
“This phenomenon leads to a cascade of reactions resulting in hyperresponsiveness of the airways, overproduction of mucus and eosinophilia (an excessively high level of white blood cells called eosinophils in the airways)”.
Today, the reference treatment for asthma is based on inhaled corticosteroids, which are not always sufficient. It is then necessary to resort to treatments with therapeutic monoclonal antibodies precisely targeting IgE. However, these drugs are both expensive and restrictive, in the form of injections sometimes for life.
A successful new trial for a vaccine
A simpler vaccine to protect against this allergic asthma? French researchers have been working on it for a while and may well come close. In a previous study, the team had shown the effectiveness of a conjugate vaccine, called Kinoid in mice. As a first success, its administration did cause a lasting production of antibodies directed specifically against IL-4 and IL-13 in mice, as well as a reduction in the symptoms of allergic asthma in animals.
This time, the same team wanted to check whether the vaccine was still able to neutralize the human IL-4 and IL-13 cytokines as well. The scientists used this time a model of allergic asthma to house dust mites in “humanized” mice, that is to say whose genes coding for the cytokines IL-4 and IL-13 have been replaced by the genes respective humans. The results are also promising: the vaccination induced a significant antibody response without decreasing the effectiveness of the vaccine, up to more than three months after the injection. A beneficial effect has also been observed on asthma and hyperreactivity of the airways.
Next step, the clinical trial
If this study is important today, it is because its publication is sufficient proof of efficacy to begin the clinical trial phase in humans. “This study provides proof of concept of the efficacy of the vaccine in neutralizing human proteins that play a key role in allergic asthma. We are thus paving the way a little more for the organization of clinical trials” confirms Laurent Reber, Inserm research director.
“A vaccination against allergic asthma represents a hope for long-term treatment of this chronic disease, and beyond that, a prospect of reducing allergy symptoms linked to other factors, since this vaccine targets molecules involved in different allergies”emphasizes Pierre Bruhns, head of the Antibodies in Therapy and Pathology Unit at the Institut Pasteur.