Persistence in Allergen Immunotherapy: A Longitudinal, Prescription Data-based Real-world Analysis

Introduction: Allergic rhinitis (AR) is a widespread disease with increasing prevalence in developed countries. The only treatment that tackles the underlying causes is allergen immunotherapy (AIT). This treatment is performed through two application routes, the subcutaneous immunotherapy (SCIT) or the sublingual immunotherapy (SLIT). However, persistence during the long course of treatment over 3 years is key for the efficacy of this treatment option. The impaired adherence significantly impacts public health resources. The aim of this study was to assess the persistence of AIT for both application routes.

Methods: IQVIA LRx was used to identify patients starting AIT between 2009 and 2018 with grass pollen (GP), early flowering tree pollen (EFTP) and house dust mite (HDM) allergens. Patients were classified within each allergen category by AIT groups (subcutaneous depigmented polymerised allergen AIT [dSCIT], other subcutaneous AIT [oSCIT] and SLIT) and age (5-11 years, 12-17 years, 18+ years). Furthermore, they were followed up for up to 3 years until the cessation of treatment. Patients, who were still on treatment after 3 years were deemed to be censored. Kaplan-Meier curves of persistence were generated and compared by log-rank tests.

Results: The number of patients included in the three allergen categories was 38,717 GP, 23,183 EFTP, and 41,728 HDM AIT. In all allergen categories and for any product group, patient persistence decreased with increasing age class with the difference between 5-11 years and 12-17 years greater than between the latter and 18+ years. The percentage of patients completing the first year of AIT was low, particularly for SLIT where 22.2%-27.1% of patients remained persistent after 12 months. The equivalent figures for dSCIT were 52.0%-64.1% and for oSCIT 38.3%-50.3%.

Conclusion: Persistence in AIT in AR was low in this retrospective prescription-based database and was clearly linked to patient age and application route.