The management of allergic rhinitis is based on symptomatic treatments. If the response is insufficient, allergen immunotherapy (ITA) may be offered in combination with conventional treatment. In this context, allergens prepared for a single individual, available in sublingual liquid form, make it possible to individualize treatment according to the individual sensitivity of patients. Data from clinical studies confirm the effectiveness of this form of ITA in preventing the occurrence of asthma-related episodes and in reducing the progression of symptoms in those who already had it. This study has the advantage of evaluating the drug in real life using data from the French national health system (SNDS).
More than 500,000 patients with or without asthma, followed over more than 7 years
The EfficAPSI study was conducted using two databases: a dispensation register from the manufacturer laboratory, bringing together patients suffering from allergic rhinitis treated with ITA in France, and data from the SNDS. Patients who initiated ITA and those who received symptomatic medications during the inclusion period from 2010 to 2013 were included and formed the exposed and control groups, respectively. The data from these two groups could be collected and analyzed over a median duration of 6.9 years and 8.2 years respectively. These patients were classified according to the existence and, where applicable, the severity of asthma. The definition used combined the dispensation of specific anti-asthma medications (omalizumab or three deliveries of inhaled corticosteroids with or without a long-acting beta-agonist), and hospitalization or long-term illness linked to severe asthma.
The overall population included 112,492 people treated with ITA, compared to 333,082 control people (mean age 37.8 to 38.8 years, 40 to 44% men). Two thirds of subjects following ITA treatment were treated for a single allergen, mainly house dust mites (32.7%).
Comparable effectiveness in different age or awareness classes
For the entire population included, the risk of a new asthma-related event (onset or worsening) was reduced by 36% in subjects taking ITA compared to the control group (i.e. an incidence of 2.4 versus 3, 6 per 100 patient-years respectively). This result was generally comparable regardless of the type of sensitization and in all age groups (33 to 44% risk reduction), even if the youngest patients (children and adults up to 24 years old) benefited from an additional reduction in risk (between 51 and 56%).
Two other definitions of asthma were used, one broad (bringing together all those who had received anti-asthma medication from a pharmacy and had data on hospitalization or long-term illness linked to asthma), the other is more specific only to severe forms of asthma (medications indicated at this stage and specific hospitalization data). The incidence of an asthma-related event was then for the first of these 13.9 per 1,000 person-years in the ITA group compared to 7.4 in the control group, and 0.3%. versus 0.5% per 1,000 patient-years for the second definition.
Among the population without asthma at the initiation of immunotherapy, the occurrence of asthma was reduced by a third according to the combined definition (Hazard ratio 0.67). The reduction was even 42% and 48% for subjects sensitized to mites and grasses respectively according to this same definition. Finally, among those who already had asthma, immunotherapy reduced the progression of asthma from the initial severity stage to the higher severity stage by a third.
The authors emphasize that the cohort followed here is representative of the French population treated for allergic rhinitis and that the results of this study could therefore be extrapolated to the population, even if they recognize a certain number of unmeasured confounding factors (smoking, pollution , lifestyle…). The use of an analysis method incorporating a propensity score nevertheless made it possible to alleviate this limitation by recruiting balanced ITA and control population groups.
Funding
This study was sponsored by Stallergenes Greer.
