Cystic fibrosis transmembrane conductance regulator (CFTR) modulator drugs target the underlying defect and improve CFTR function. They are a part of standard care in many countries, but not all patients are eligible for these drugs due to age and genotype. Here, we aimed to determine the characteristics of non‐eligible patients for CFTR modulators in the CF registry of Turkey (CFRT) to highlight their clinical needs.

This retrospective cohort study included CF patient data from the CFRT in 2021. The decision of eligibility for the CFTR modulator was determined according to the ‘Vertex treatment‐Finder' on the Vertex® website. Demographic and clinical characteristics of patients were compared between eligible (group 1) and ineligible (group 2) groups for CFTR modulators.

Among the study population (N = 1527), 873 (57.2%) were in group 1 and 654 (42.8%) were in group 2. There was no statistical difference between groups regarding sex, meconium ileus history, diagnoses via newborn screening, FEV1 z‐score, CF‐associated complications, organ transplant history, and death. Patients in group 2 had a higher incidence of pancreatic insufficiency (87.7% vs. 83.2%, p = .010), lower median height z‐scores (−0.87 vs. −0.55, p < .001), lower median body mass index z‐scores (−0.65 vs. −0.50, p < .001), longer days receiving antibiotics due to pulmonary exacerbation (0 [interquartile range, IQR: 0–2] vs. 0 [IQR: 0–7], p = 0.001), and more non‐invasive ventilation support (2.6% vs. 0.9%, p = 0.008) than patients in group 1.

The ineligible group had worse clinical outcomes than the eligible group. This highlights their need for life‐changing drugs to improve clinical outcomes.