Cystic Fibrosis — RACP Adult Medicine MCQ

Instant feedback + full explanation. One question, done properly.

ModerateRespiratoryCystic FibrosisRACP Adult Medicine

A 28-year-old man with cystic fibrosis (homozygous F508del mutation) has an FEV1 of 55% predicted with frequent exacerbations. He is on standard CF therapy. What disease-modifying therapy is most appropriate?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Elexacaftor/tezacaftor/ivacaftor (Trikafta)

Elexacaftor/tezacaftor/ivacaftor (ETI – marketed as Trikafta/Kaftrio) is a triple CFTR modulator therapy that has revolutionised CF care. It is effective for patients with at least one F508del mutation (~90% of CF patients). The ECLIPSE trial showed a 14% absolute improvement in FEV1 and 63% reduction in exacerbations. ETI is PBS-listed in Australia for eligible patients aged ≥6 years.

Reference: Cystic Fibrosis Australia – 2024 – CF Clinical Guidelines; PBS – 2025 – CFTR Modulator Listings