The real-world oral corticosteroid burden in patients starting anti-interleukin-5 therapy

Rationale: Currently, three biologics targeting the IL-5 pathway (mepolizumab, reslizumab and benralizumab) are approved for the treatment of severe eosinophilic asthma. Oral corticosteroid (OCS) dose reduction is an important treatment goal of these new drugs, in order to reduce OCS-related side effects.
Phase 3 trials have shown the OCS-sparing effect of mepolizumab and benralizumab, with significant reductions in median daily OCS dose after 6 months of treatment. Yet, data on the long-term cumulative OCS-dose before and after anti-IL-5 treatment initiation in a real-world population are lacking. Insight in the biologic-induced effects on this long-term OCS burden may provide further awareness on the achieved effects of anti-IL-5 therapy and add in the justification of the application of expensive biological therapy for severe asthma.
Objective: To study the change in cumulative OCS dose between 2 years before and 2 years after anti-IL-5 initiation in severe eosinophilic asthma.
Study design: Observational, retrospective cohort study.
Study population: Patients in the national RAPSODI registry, receiving anti-IL-5 therapy in the treatment of severe asthma before 1/1/2019.
Main study parameters/endpoints:
The main study parameter is the cumulative OCS dose (mg) and change in this cumulative dose in the two years before and after initiating anti-IL-5 therapy for severe asthma.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The selected patients are already included in the RAPSODI registry and treated for their severe asthma. The current study does not have an intervention. Therefore, the burden and risks associated with participation are non-existent.

There is a large difference in long term OCS use between before anti-IL-5 and after antil-IL-5 therapy

For the selected patients, the startdate of anti-IL-5 therapy will be determined. The change in cumulative OCS dose between 2 years before and 2 years after start of anti-IL-5 therapy will be determined retrospectively by collecting communal pharmacy data.
The course of the mean OCS dose per 3 month periods, during 2 years before and after initiating anti-IL-5 treatment will be determined by splitting the gathered pharmacy data in trimesters, retrospectively.