Elexacaftor / Tezacaftor / Ivacaftor

How it works

Elexacaftor and tezacaftor are correctors that increase the amount of CFTR protein at the cell surface, while ivacaftor is a potentiator that enhances chloride transport through the channel.

Prescribing in practice

• It can cause transaminase elevations and liver injury, so liver function must be checked before and during treatment and the drug interrupted if significant derangement occurs.
• It is a sensitive substrate of CYP3A, so strong inducers reduce its effect and dosing must be adjusted with strong inhibitors; care is needed with concomitant interacting drugs.
• Cases of cataract have been reported in children, so baseline and follow-up ophthalmological examination is recommended in paediatric patients.

Monitoring

Monitor liver function tests before and periodically during treatment, and arrange eye examinations in children.

Counselling the patient

• Take the medicine with fat-containing food to help absorption.
• Attend your blood tests and eye checks as arranged, and report yellowing of the skin or eyes or abdominal pain.
• Tell your team about any new medicines, including over-the-counter and herbal products such as St John's wort.

Evidence & guidelines

Trials of elexacaftor/tezacaftor/ivacaftor demonstrated marked improvements in lung function in eligible patients with cystic fibrosis.