Monitoring ETI effects over 1.7 years in an infant treated in utero, via breast milk and granules by repeated faecal elastase measurements

Pancreatic insufficiency is a major complication of cystic fibrosis (CF), which traditionally has been managed with pancreatic enzyme replacement therapy in the vast majority of CF patients, even in the era of highly effective cystic fibrosis transmembrane conductance regulator modulator (CFTRm) therapy. We report on a 1.7 year old male infant with CF who was exposed to ETI both in utero and postpartum, via breast milk and oral granules. Repeated faecal elastase analyses were carried out to monitor pancreatic function closely, with normal levels at birth. Although faecal elastase values fluctuated over time, it never dropped below 100 µg/g for several subsequent measurements, while the infant continued to receive breast milk. However, at the age of 8 months PERT was initiated. ETI was introduced at 9 months of age in the form of crushed tablets as an individualised treatment, following a sustained increase in faecal elastase to >200µg/g to date. 3 weeks after starting oral ETI therapy, PERT was discontinued. With this case report we would like to show that continuous pre- and postnatal ETI exposure can maintain pancreatic function in CF for at least 1.7 years.