D2.174 - Patient survey to determine the minimal clinically important difference for a combined symptom and medication score in grass AIT

Since the inception of the EAACI recommended Combined Symptom and Medication Score (CSMS_0-6) score for Phase III allergen immunotherapy (AIT) trials, no generalizable and well justified recommendations for a minimal important clinical difference (MCID) have been established. Here, a patient-centric approach was applied to generate direct patient evidence on a MCID for a grass allergy product.

A patient survey was conducted in Germany and Austria, aiming to identify the MCID for a grass AIT product using a series of consecutive questions covering their 2 most severe symptoms (based on the CSMS nose and eye score definitions). Only patients with self-rated moderate to severe grass allergy were selected through the pollen information network in Vienna (www.polleninformation.at) and a company website (www.bencard.com). Furthermore, the link to the survey was shared by the German Patient Organization DAAB.

1071 moderate to severe grass allergic participants completed the survey. The median and 3^rd quartile step improvement considered clinically relevant by patients was 1 step in their most severe symptom only (e.g. improvement from severe to moderate). The minority of patients (14.8%) considered the MCID to be >1 step improvement on a single symptom or ≥1 steps on their 2 most severe symptoms. This translated in an average MCID on the EAACI CSMS_0-6 scale ranging from 0.21 to 0.23 points.

This survey provides direct patient evidence of a MCID in patients with grass-pollen-induced allergic rhinitis. The vast majority of patients considered a 1 step improvement in their most severe symptom alone being clinically relevant, translating into an MCID for the CSMS_0-6 ranging from 0.21-0.23 points.