The return of spring also signals that of pollen. This is not encouraging for a certain number of asthmatics. This period is indeed for them synonymous with the onset of trouble, which can sometimes lead to acute attacks, or even to hospital due to significant breathing difficulties. Asthma is a chronic disease that affects 4 million people in France, half of whose cases have an allergic origin.
If for a good part of them, a good shot of Ventolin or corticosteroids allows them to cope, for the most severe cases the treatment is much more complex and restrictive. This is the case of the one based on therapeutic antibodies which prove to be very effective.
These will block the cytokines IL-4 and IL-13, immune proteins that are produced in allergic subjects during contact with dust mites, molds or any other allergenic sources. But the presence of this battalion ready to fight the enemy from elsewhere is not without consequences. It causes cascading reactions such as the development of a strong cough or inflammation of the respiratory tract. Injected intravenously or cutaneously, monoclonal antibodies will then play a regulatory role by targeting cytokines.
Expensive and burdensome current treatment
In France, 40,000 to 50,000 patients have access to this treatment each year. But, in reality, they could be ten times more numerous. “Unfortunately, these therapeutic antibodies are very expensive: we are talking about 15,000 euros per year and per patient. And with a need to reinject the antibodies every month, which is a real constraint for the patients and the hospital, ”says Laurent Reber, director of research at the Toulouse Institute of Infectious and Inflammatory Diseases (Inserm / CNRS /UPS).
For several years, with the Pasteur Institute and the Neovacs company, his team has been working on the development of an effective vaccine against allergic asthma. “We said to ourselves that we were going to target the same IL-4 and IL-13 proteins, but with a vaccine so that our body would produce its antibodies and do so over the long term. With the double aim of both reducing the cost and the number of injections in patients”, continues the researcher.
Two years ago, they did the proof of concept in mice, showing that it was possible to neutralize these famous IL-4 and IL-13 proteins with a vaccine. With an efficiency rate that was still 70% one year after the injection. But before moving on to the clinical trial phase, it still had to be proven that there was a good chance that it could also work on humans.
“We used what are called humanized mice, mice in which we replaced the genes encoding murine IL-4 and IL-13 with genes encoding these two human proteins,” explains Laurent Reber. The results, which show “very strong protection” of the human vaccine in these humanized mice, have just been published in the specialized journal allergy.
All the lights are green for clinical trials
The lung inflammation of these mice, their respiratory discomfort and their overproduction had considerably decreased. “On these parameters we have a very high response rate, we have a protection rate of around 90%”, assures the scientist.
A promising result, especially since it could be extended to other pathologies of allergic origin, in particular food, or even atopic dermatitis. The two targeted proteins are indeed involved in these pathologies.
However, these results now need to be validated in clinical trials which should take place in two stages over the next few years. The first cohort of patients selected will test the safety of the vaccine, to ensure that it presents no danger. The second cohort will verify its effectiveness and duration. Even if all the lights are green, the vaccine should not see the light of day for a few years