Elevated serum lipase in infants with cystic fibrosis exposed to prenatal and postnatal elexacaftor/tezacaftor/ivacaftor.

Cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction leads to progressive exocrine pancreatic insufficiency, resulting in difficulty in the secretion of digestive enzymes and subsequent malabsorption of nutrients. Case reports have described preserved pancreatic function with prenatal elexacaftor/tezacaftor/ivacaftor (ETI) exposure. However, little is known about pancreatic function and injury as ETI exposure decreases postnatally. Here, we discuss four infants with cystic fibrosis (CF) who were prenatally exposed to ETI, with pancreatic function ranging from preserved to mild insufficiency. All four developed elevated serum lipase, a marker of pancreatic cell injury, as ETI exposure diminished after birth. These cases illustrate the relationship between sweat chloride as a biomarker of CFTR function, fecal elastase as a biomarker of pancreatic function, and serum lipase a biomarker of pancreatic cell injury. While prenatal ETI exposure can preserve pancreatic function in infants with CF, ongoing postnatal ETI exposure may be necessary to prevent pancreatic damage, suggesting a role for early ETI therapy in prenatally exposed infants.