Background: Recently, elexacaftor/tezacaftor/ivacaftor (ETI), the turning point in the course of Cystic fibrosis (CF), was also approved for children with CF (cwCF) aged 6–11years carrying at least one F508del –mutation. Modulating the causative deficiency in the CF transmembrane conductance regulator channel was found to substantially improve the crucially affected respiratory and digestive CF–manifestations. In this regard, for people with CF aged ≥12years, we previously found that ETI decreases significantly abdominal symptoms (AS) using the CFAbd–Score©. Aims: Assessing changes in AS after ETI initiation in cwCF aged 6–11years with the novel pediatric Patient–Reported Outcome Measure CFAbd–Score.kid©. Methods: The CFAbd–Score.kid©, specially developed for cwCF aged <12years, implements pictograms, easy language and children–oriented response strategies, comprising 29 CF–specific gastrointestinal items from five domains. Its scoring algorithm developed following FDA guidelines weights items and domains differently, reaching a maximum of 100 points. CwCF completing at least one questionnaire before ETI initiation and another one during ETI therapy were included. Results: In four German CF centers, a total of n=52 cwCF (mean age 8.3±2.2years) were included, completing a total of n=293 questionnaires. During ETI therapy, significant decreases were observed for mean total CFAbd–Score.kid© (–31%/p<0.0001) as well as for mean sub–scores of ′pain′ (–26%/p<0.01), ′QoL impairment′ (–48%/p<0.01), ′disorders of bowel movement′ (–32%/p<0.0001) and ′disorders of appetite′ (–42%/p<0.05). Conclusion: Among cwCF aged 6–11years, AS captured with the novel CFAbd–Score.kid© significantly decreased during the novel ETI treatment. Simultaneously, CFAbd–Score.kid© proved to be sensitive to ETI–induced changes in AS. Further validation steps and international implementation are currently in progress.

This study has been supported by an Independent Medical Grant for Investigator Initiated Study by Vertex Corp. IIS–ISS–2021–109677

NCT03052283

This study has been supported by an Independent Medical Grant for Investigator Initiated Study by Vertex Corp. IIS-ISS-2021-109677

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study has been conducted in strict accordance with the ethical guidelines of the Declaration of Helsinki and was approved by the Brandenburg Medical School (MHB) ethics committee (registration number E–01–20200519). Furthermore, it has been registered in ClinicalTrials.gov identifier: NCT03052283, Development and Validation of a Disease Specific PROM to Assess Abdominal Involvement in pwCF (CFAbd–Score© / CFAbd–Score.kid©).

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All data produced in the present study are available upon reasonable request to the authors