Article breakdown

Quantitative Systems Toxicology Predicts Ivacaftor-Induced Oxidative Stress Contributes to CFTR Modulator Hepatotoxicity.

Clinical pharmacology and therapeutics • 2026 Jan • Vol 119, 208-218. PMID 40985277.

This study suggests the cystic fibrosis treatment elexacaftor/tezacaftor/ivacaftor may cause liver problems mainly because ivacaftor triggers oxidative stress in liver cells. A computer toxicity model produced liver enzyme elevations at a rate close to clinical data and suggested that lowering the dose or giving antioxidants might help prevent this side effect. These prevention strategies were explored in lab and computer studies, not tested in patients in this abstract.

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In short

What this paper found

This study suggests the cystic fibrosis treatment elexacaftor/tezacaftor/ivacaftor may cause liver problems mainly because ivacaftor triggers oxidative stress in liver cells.

A computer toxicity model produced liver enzyme elevations at a rate close to clinical data and suggested that lowering the dose or giving antioxidants might help prevent this side effect.

These prevention strategies were explored in lab and computer studies, not tested in patients in this abstract.

Deep dive

What the paper is actually saying

Why This Paper Exists

This paper addresses a practical safety problem: the ETI treatment has improved life for many people with cystic fibrosis, but it can also raise liver enzymes and has been linked to drug-induced liver injury. Because the reason for this liver toxicity has been unclear, it has been hard to develop ways to lower that risk.

What The Authors Wanted To Answer

The authors wanted to identify which ETI drug contributes most to the liver toxicity and what biological mechanism may explain it.

How The Study Was Done

The study used in vitro assays and quantitative systems toxicology modeling with DILIsym. The modeling was used to estimate how often ETI might cause liver enzyme elevations and to simulate possible ways to reduce that risk. The abstract does not clearly label a formal study design beyond lab testing plus modeling.

What The Study Found

Ivacaftor was identified as the main contributor to ETI-related liver injury in this analysis. The proposed mechanism was reactive oxygen species production, leading to mitochondrial dysfunction through electron transport chain inhibition. In DILIsym, daily ETI dosing produced predicted liver enzyme elevations in 6.0% of simulations, compared with 8.0% in clinical data. The simulations also suggested that dose reduction and antioxidant use could lower the frequency of these elevations.

Takeaway

The abstract supports ivacaftor-driven oxidative stress as a likely explanation for some ETI-related liver toxicity. It also points to dose reduction and antioxidants as possible risk-reduction approaches, but the evidence presented here is from lab and model-based work rather than direct patient testing.

Limits

What this abstract does not fully answer

The abstract does not clearly state a formal study type beyond in vitro assays and computer modeling.

The proposed mechanism is supported by lab findings and DILIsym simulations, not direct proof in patients.

The suggested prevention approaches, such as dose reduction and antioxidants, were simulated rather than clinically tested in the abstract.

Key numbers

Numbers the abstract makes important

6.0%

Frequency of liver enzyme elevations predicted by the DILIsym simulations during daily ETI dosing.

8.0%

Frequency of liver enzyme elevations in the clinical data used as a comparison point for the model.

Source abstract

Original abstract sections

Abstract

Cystic fibrosis (CF) is a chronic hereditary disease that affects tens of thousands of people worldwide. The introduction of CFTR modulator therapies such as elexacaftor/tezacaftor/ivacaftor (ETI) has significantly improved the quality of life of people with CF. However, ETI has been shown in clinical trials to cause elevations in liver enzymes, and real-world cases of drug-induced liver injury (DILI) have also been reported. The mechanism of ETI-mediated DILI is currently unknown, hindering the development of more effective mitigation strategies for this adverse reaction. Through in vitro assays and quantitative systems toxicology modeling using DILIsym, this study revealed that ivacaftor contributed most significantly to ETI-mediated DILI, primarily via reactive oxygen species production, resulting in mitochondrial dysfunction due to electron transport chain inhibition. DILIsym modeling also predicted liver enzyme elevations following daily dosing of ETI at a comparable frequency (6.0%) to that of clinical data (8.0%). Simulations of the therapeutic effects of DILI mitigation strategies for ETI showed that dose reduction and antioxidant administration may significantly reduce the frequency of liver enzyme elevations due to ETI.