Long-term effectiveness of allergy immunotherapy

The REACT study: Demonstrating long-term effectiveness of allergy immunotherapy in the real world

By applying high scientific standards and rigorous methodology, the REACT (REAl world effeCtiveness of allergy immunoTherapy) study demonstrated that allergy immunotherapy (AIT) can have long-term benefits for patients in the real world.

The aim of the REACT study was to provide insights into some of the most important but, as yet unanswered questions in the field of AIT. One of these questions is whether the efficacy shown in randomised, controlled trials (RCTs) is generalisable to broader patient populations when treated in everyday clinical practice? Another important question, considering that AIT is a causal treatment, is whether the effects of AIT are sustained over the long-term – i.e., beyond the follow-up period for RCTs?

Following high scientific standards and using real world data from clinical practice, the REACT study assessed the effectiveness of AIT in more than 92,000 patients for up to 9 years. The study design is described here and the patient population is described here.

AIT is associated with long-term, sustained reductions in AR medication use for up to nine years after starting treatment

The primary outcome of the study was to assess the impact of AIT treatment on the frequency of prescriptions for symptom-relieving AR medications, such as antihistamines and intranasal corticosteroids (INCS). In this study, both the AIT-treated group and the control group saw reductions in AR prescriptions during the follow-up-years versus the pre-index year, but the AIT-treated group saw greater reductions, and this was sustained for 9 years. The overall reductions were consistent across drug classes, but slightly greater for antihistamines compared to INCS. Reductions in AR prescriptions were robust across all investigated subgroups.

This robust and comprehensive real world evidence study complements the evidence from RCTs and provides insights into how AIT works in the real world

With a rigorous methodology, a large sample size, and long-term follow up, the REACT study further substantiates the existing evidence from RCTs and adds new information about the potential benefits of AIT beyond the follow-up conducted after RCTs. The real life effectiveness of AIT was demonstrated with sustained reductions in AR prescriptions. The findings emphasised AIT as a clinically relevant treatment option for patients with respiratory allergies. Additional benefits of AIT in patients with asthma were found in this study and are described here.

More about long-term efficacy of AIT in RCTs.

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