Elexacaftor-Tezacaftor-Ivacaftor Improves Sinonasal Outcomes in Young Children With Cystic Fibrosis.

Abstract

Background: Severe chronic rhinosinusitis (CRS) is a near universal manifestation of cystic fibrosis. Elexacaftor/tezacaftor/ivacaftor (ETI) is an oral, small molecule, highly effective Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) corrector-potentiator drug. In people with cystic fibrosis age > 12 years, ETI improves sinonasal symptoms, endoscopy findings, polyp size, and radiologic findings. This study evaluates changes in CRS in children ages 6-12 years newly started on ETI.

Methods: This was a prospective, three center, pre-post study of 11 children age 6-11 years newly started on ETI. Study endpoints included the SN-5 sinonasal health survey, Sniffin' Kids olfaction test, a sinus computerized tomography (CT) scan, and nasal endoscopy with mucus sampling for full-length 16S rRNA sequencing microbiome analysis. Study visits were conducted before ETI and at a median of 9 months after treatment initiation.

Results: ETI lead to improvement in symptoms, endoscopy scores and radiologic findings of CRS. Olfaction was below normal at baseline and did not improve. The sinonasal microbiome was dominated by typically commensal organisms before and after treatment for most participants. Additionally, Staphylococcus aureus was found in five participants at baseline and six participants on treatment.

Conclusions: ETI improves sinonasal symptoms and endoscopy findings in children 6-11 years of age. Olfaction did not improve with ETI treatment in this age group, suggesting that olfactory dysfunction associated with CF is established early in life. This younger cohort of pediatric patients presented with abundant Staphylococcus aureus and only very rare Pseudomonas aeruginosa at baseline or after treatment.