Cystic fibrosis (CF) is a genetic condition of impaired membrane electrolyte transport and is characterised by defects in the production and function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Ground-breaking CFTR modulator therapy has resulted in a notable shift in the clinical presentation and progressive nature of CF, across both pulmonary and extrapulmonary systems. Access to CFTR modulator therapies in people with CF is occurring in a staged, descending age process, with clinical trials focusing primarily on safety and efficacy. There is a lack of robust, real-world longitudinal data on CFTR modulator therapy in infants and young children where extrapulmonary outcomes such as growth, micronutrient status and pancreatic function are the key focus.

Pancreatic, nutritional and clinical outcomes in children 0–5 years with CF during the first 2 years of CFTR modulator therapy (PaNC) is a prospective cohort study involving all eight tertiary paediatric CF centres in Australia. Infants and children 4 months to 5 years of age who are eligible for elexacaftor/tezacaftor/ivacaftor (ETI) or ivacaftor (IVA) meet the inclusion criteria for PaNC, with a total eligible cohort of 303 children at the commencement of recruitment. The primary outcomes are change in weight-for-length/body mass index z score and change in serum micronutrient status, at 6–12 monthly intervals, during the first 2 years of treatment with ETI or IVA. Secondary outcomes include change in exocrine pancreatic function, measured by faecal elastase-1, change in the use and dose of pancreatic enzyme replacement therapy, nutritional and gastrointestinal therapies and change in sweat chloride levels. Linear mixed modelling will be used to analyse primary and secondary endpoints. This protocol is reported in accordance with ‘The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement’ reporting guidelines.

Overarching governance and ethics approval has been granted by Monash Health Human Research Ethics Committee, in addition to all eight sites receiving site-specific authorisation approvals prior to the commencement of recruitment. Opportunities for CF consumers to be involved in targeted dissemination plans will be initiated via CF Australia at the completion of the study period. Additionally, a summary of non-identifiable results will be provided to CF consumers and CF healthcare providers via scientific and lay conferences and via peer-reviewed journals.

ACTRN12624001185550; Pre-results.