Cystic fibrosis (CF) transmembrane conductance regulator modulators are a cornerstone of CF treatment. However, many patients develop CF liver disease (CFLD) over time, and previous data indicate a risk for transaminase elevation with modulator use. Elexacaftor/tezacaftor/ivacaftor is a commonly prescribed modulator with broad efficacy among CF genomic profiles. Theoretically, elexacaftor/tezacaftor/ivacaftor drug-induced liver injury could exacerbate and further worsen CFLD, but holding modulators can cause a decline in clinical status.
This study was designed to determine the real-world incidence of transaminase elevations in adult patients with CF taking elexacaftor/tezacaftor/ivacaftor.
This exploratory, retrospective descriptive study included all adults with CF-prescribed elexacaftor/tezacaftor/ivacaftor at our institution’s outpatient CF clinic. We explored transaminase elevations in 2 separate outcomes: incidence of transaminase elevations of more than 3 times the upper limit of normal (ULN), and transaminase elevations of 25% or more above baseline.
83 patients were prescribed elexacaftor/tezacaftor/ivacaftor. Nine patients (11%) experienced an elevation of more than 3 times ULN and 62 (75%) experienced an elevation of 25% or more above baseline. The median days to transaminase elevation were 108 and 135 days, respectively. Therapy was not discontinued due to transaminase elevations in any of the patients.
Transaminase elevations among adults taking elexacaftor/tezacaftor/ivacaftor were common but did not result in discontinuation of therapy. Pharmacists should be reassured of the liver safety profile of this important medication for patients with CF.

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