Gilbert’s Syndrome Leads to Elevated Bilirubin after Initiation of
Elexacaftor/Tezacaftor/Ivacaftor in People with Cystic Fibrosis
Abstract
Nine people with cystic fibrosis (pwCF) were found to have isolated
elevations in serum total bilirubin after starting
elexacaftor/tezacaftor/ivacaftor (ETI) that were associated with
Gilbert’s Syndrome. In longitudinal examination, total bilirubin levels
increased substantially after initiation of ETI without elevations in
liver transaminases in those with this syndrome. Because elevated
bilirubin levels in Gilbert’s Syndrome are benign, ETI was able to be
continued in these individuals. Genetic testing for this relatively
common syndrome should be strongly considered for pwCF experiencing
isolated hyperbilirubinemia after starting ETI, since appropriate
diagnosis may help pwCF avoid unnecessary interruption in this therapy
with significant health benefits in CF.