Is Symdeko affected by genetics?
Partially. 1 of 2 ingredients has pharmacogenetic evidence.
Symdeko contains 2 active ingredients, and 1 of them has published pharmacogenetic guidelines. The relevant gene is CFTR. Your genotype can change how that ingredient behaves in your body, while the other ingredients aren't affected by genetics in any clinically established way. The strongest evidence level on this page is Strong, from the published guidelines shown below.
Pharmacogenetic guidelines are written for one ingredient at a time, so the guidance below is for each ingredient on its own. What your genes mean for a combination product is less clear, because the dose and the other ingredients can change things. If you take Symdeko, it's worth talking over with your prescriber or pharmacist. How we handle combination products.
What's in Symdeko
Tezacaftor No known pharmacogenetics
No strong published pharmacogenetic guideline currently applies to tezacaftor.
Ivacaftor Affected by CFTR
Affected by CFTR. Guidance from CPIC, strong evidence.
Read the full ivacaftor genetics guideIvacaftor phenotype recommendations
Published guidance from CPIC on how ivacaftor should be dosed or substituted based on your CFTR phenotype.
| Phenotype | What it means | Recommendation | Evidence |
|---|---|---|---|
| ivacaftor responsiveCFTR | Your CFTR result means this drug is likely to work for you. It helps the CFTR protein work better and can improve lung function. | CPIC Use ivacaftor according to the product label |
Strong |
| ivacaftor non-responsiveCFTR | Your CFTR result means this drug is unlikely to work for you. A different treatment is usually suggested. | CPIC Ivacaftor is not recommended |
Moderate |
| ivacaftor irrelevantCFTR | The impact of your genotype on response to this drug is unknown | CPIC Initiate therapy with recommended starting dose. |
Not rated |
| Not availableCFTR | The impact of your genotype on response to this drug is unknown | CPIC Initiate therapy with recommended starting dose. |
Not rated |
Source: CPIC
The gene behind the guidance
CFTR Cystic Fibrosis Transmembrane Conductance Regulator
CFTR is the chloride channel that's broken in cystic fibrosis. Modern CF therapies (ivacaftor, tezacaftor, elexacaftor, and their combinations) restore partial channel function, but only for patients whose specific CFTR variant produces a protein the drugs can act on. The FDA labels each modulator with the exact list of responsive variants.
Patients with at least one gating variant like G551D respond dramatically to ivacaftor. Patients homozygous for F508del benefit from the triple combination (Trikafta), but not from ivacaftor alone.
See all drugs affected by CFTRFind out how your genetics affect Symdeko
Informational only, not medical advice. Pharmacogenetic guidance describes population-level patterns; your individual response depends on many factors. Never start, stop, or change a medication without talking to your prescribing clinician.