D2.200 - An interim analysis of a multiCenter study on the effect of SCIT on tic symptoms in Children and Adolescents with HDM aLlergy and coMorbid tic disorders (CALM study)

Allergic diseases impact nearly one-third of the global population, leading to significant mental health challenges, reduced quality of life, and economic burdens. Emerging evidence suggests a connection between allergic diseases and tic disorders (TD). As allergen immunotherapy (AIT) is the only treatment known to modify the progression of allergic diseases, this study aims to investigate the effect of subcutaneous immunotherapy (SCIT)  on tic symptoms in Chinese children and adolescent patients with house dust mite(HDM) allergy and comorbid TD.

The CALM study is an ongoing multicenter prospective observational study  enrolling patients aged 5–18 with HDM-induced allergy and comorbid TD. Participants were divided into a SCIT group (standard TD treatment + SCIT) and a non-AIT group (TD treatment + symptomatic allergy medication). Participants were divided into a SCIT group (standard TD treatment + SCIT) and a non-AIT group (TD treatment + symptomatic allergy medication). This interim analysis evaluated outcomes using the Yale Global Tic Severity Scale (YGTSS) and Visual Analogue Scale (VAS). 

Of 35 enrolled participants (SCIT: n=11; non-AIT: n=24), baseline median YGTSS scores were 17 (IQR 12 to 24) and 15 (IQR 11 to 23), respectively Preliminary 6-month follow-up data were available for 12 participants (n=6 in the SCIT group; n=6 in the non-AIT group). The SCIT group showed a greater mean reduction in YGTSS score [−12.5 (IQR −34 to −6)] compared to the non-AIT group  [−4.5 (IQR −20 to −2)] with non-statistical significance(p = 0.1474). Conversely, the median percentage improvement in combined nasal and ocular VAS scores was significantly higher in the SCIT group [63.8% (IQR 56.8% to 70.0%)] compared to the non-AIT group [41.9% (IQR 34.5% to 50.0%); p = 0.0202].

This interim analysis revealed a significant between-group difference in VAS scores after 6 months of AIT treatment. Though the reduction in YGTSS scores was not statistically significant, a trend towards greater improvement was observed in the AIT group. This lack of significance may stem from the limited sample size and short observation period at this preliminary stage. Continued enrollment and longer-term follow-up within the CALM study are ongoing to validate these findings.