Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.
Ivacaftor is a CFTR modulator for cystic fibrosis. In people with certain CFTR variants the CFTR protein reaches the cell surface but its channel stays mostly closed; ivacaftor helps hold the channel open, so chloride and water move again and mucus becomes less thick. It is sold as Kalydeco and is also part of combination medicines.
Ivacaftor only works for people whose cystic fibrosis is caused by particular variants in the CFTR gene itself, the gene behind the condition. The first approved was G551D (rs75527207); the list has since grown to around a hundred variants, each tested for response. CPIC has published a guideline on CFTR and ivacaftor, and the US drug label lists the responsive variants. Nearly all the studies on this page concern CFTR variants.
Clinical guidelines that name a gene for Ivacaftor. They sort people into groups by the gene copies they carry.
US FDA: CFTR. ivacaftor responsive in CF patients.
Every published finding on gene variants and Ivacaftor. Upload your DNA file to see which of these rows apply to you.
PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.
CFTR rs75527207: Level 1A · replicated. Efficacy: Cystic Fibrosis. 30.
CFTR rs78655421: Level 1A · replicated. Efficacy: Cystic Fibrosis. 6.
CFTR rs121908755: Level 1A · replicated. Efficacy: Cystic Fibrosis. 5.
CFTR rs121908757: Level 1A · replicated. Efficacy: Cystic Fibrosis. 4.
Studies of how well it worked in people carrying a variant.
CFTR rs113993960: Allele del is associated with increased response to ivacaftor.
Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.
More drugs from the same category
Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.
Content updated September 2026.
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