Repeated rhinitis, asthma attacks, disturbed nights, chronic fatigue… Respiratory allergies weigh heavily on the daily lives of millions of people. According to a real-life French study, more than eight out of ten patients treated with sublingual allergen immunotherapy report a significant improvement in their condition. A step forward which could weigh on discussions around maintaining reimbursement for this support.
When patients themselves tell about the effectiveness of desensitization
For those who suffer from respiratory allergies, spring does not always mean renewal. Pollens, mites, mold and even cat hair can turn everyday life into an obstacle course: stuffy nose, incessant sneezing, irritated eyes, fragmented sleep, difficulty concentrating at school or at work.
Faced with these symptoms, antihistamines and other treatments often provide temporary relief. But only one approach is today capable of acting on the very cause of the allergy: allergen immunotherapy, better known as desensitization.
This strategy consists of gradually exposing the body to the allergen responsible for the symptoms in order to teach the immune system to tolerate it. Now mainly administered in the form of drops or tablets to be placed under the tongue, it must be followed for at least three years. It is precisely the perceived effectiveness of this approach that the ERAPP study, carried out by the team of Pascal Demoly and Davide Caimmi at the Desbrest Institute of Epidemiology and Public Health in Montpellier, sought to measure.
The survey collected responses from nearly 9,500 patients ages five and older. Among them, nearly 4,800 had started their treatment less than six months ago. The vast majority suffered from allergic rhinitis and around a quarter also had asthma.
- The results are particularly striking. After one year of treatment, 84% of participants said they were satisfied with its overall effect. The benefits concern the symptoms of rhinitis as well as the control of asthma and the quality of sleep;
- Even more surprising, the improvements appear quickly. From the sixth month, more than 78% of patients report an improvement in their condition and 40% indicate that they no longer have symptoms.
“In total, nearly 9,500 patients aged 5 and over participated, of whom 4,794 had started treatment less than 6 months ago. Nine in 10 suffered from allergic rhinitis and around a quarter had asthma.explains Davide Caimmi.
This data provides valuable insight: beyond clinical trials, it reflects the experience experienced by patients in their daily lives.
A treatment called into question… then re-evaluated in light of the field
If this study saw the light of day, it is also because desensitization has been going through a period of uncertainty for several years. In 2018, the High Authority for Health (HAS) suspended reimbursement for subcutaneous immunotherapy and reduced that of oral forms, considering that new evidence of effectiveness was necessary. The available scientific data then presented results that were sometimes difficult to compare. The targeted allergens differed from one study to another, as did the formulations used, the patient profiles and the pathologies studied.
However, the specialists did not question the very principle of desensitization. The objective of ERAPP was therefore to complement traditional clinical trials with a more faithful picture of what happens in real life.
“Alongside the new clinical studies launched by pharmaceutical laboratories, we wanted to meet the HAS requirement with additional data, obtained from studies carried out in real life, which reflect the effectiveness perceived by patients and their satisfaction.he explains.
The study also highlights a paradox well known to doctors: when symptoms improve significantly, some patients gradually relax their compliance.
“Medication compliance, that is, the ability to take the medication correctly, tends to decline over time, as with any chronic treatment. Paradoxically, the most relieved patients are often those who are the least compliant.”observes Davide Caimmi.
An understandable phenomenon. When the pollen disappears and the symptoms fade, many feel they are cured. However, stopping treatment prematurely risks compromising its long-term benefits. Because desensitization takes time. And it is precisely this duration that allows it to act in depth.
Three years to re-educate the immune system and change the trajectory of the disease
Unlike symptomatic treatments, desensitization does not only seek to make allergic manifestations disappear. Its ambition is much deeper: to permanently modify the functioning of the immune system.
In allergic people, certain immune cells promote an excessive inflammatory reaction to harmless substances. Gradually, this hyperreactivity can worsen and lead to the appearance of new allergies or the progression towards more severe forms, notably asthma.
Allergen immunotherapy works by rebalancing this system. Administered under the tongue, very small quantities of allergens are captured by specialized cells which will gradually induce the formation of regulatory T lymphocytes, true “guardians of tolerance”. Little by little, the body learns to no longer consider the allergen as a threat. This immune remodeling is slow. Experts estimate that it generally takes three full years of treatment — or three successive pollen seasons — to achieve a lasting effect after stopping therapy.
Beyond the immediate relief, researchers also highlight its potential impact on what allergists call the “atopy trajectory.” This trajectory describes the natural evolution of many allergic diseases: eczema in childhood can be followed by allergic rhinitis, then asthma, sometimes accompanied by other allergic manifestations. To date, allergen immunotherapy remains the only therapeutic strategy capable of slowing or even interrupting this progression.
The ERAPP results should soon be supplemented by new analyzes focusing on patient expectations and the impact of treatment depending on the type of allergy concerned. Another international study carried out among doctors in 28 countries is also expected. For researchers, this data already constitutes a solid argument in favor of maintaining appropriate reimbursement. For patients, above all, they provide valuable confirmation: despite its duration and the constraints it imposes, desensitization can really transform daily life and, sometimes, permanently change the course of the disease.