elexacaftor-tezacaftor-ivacaftor
Brand: Trikafta
Prototype Drug
Drug Class: CFTR modulator — triple combination
Drug Family: CFTR modulator
Subclass: CFTR corrector + corrector + potentiator combination
Organ Systems: respiratory
Mechanism of Action
Triple-combination CFTR modulator: elexacaftor (next-generation corrector) and tezacaftor (corrector) bind to different sites on CFTR to improve folding and trafficking of misprocessed F508del CFTR to the cell surface; ivacaftor (potentiator) then increases the open probability of the CFTR channel at the surface — together restoring meaningful chloride and bicarbonate transport in F508del CF patients.
CFTR protein — processing (elexacaftor and tezacaftor) and gating (ivacaftor)
Indications
- cystic fibrosis in patients aged 2 years and older with at least one F508del mutation in the CFTR gene (approximately 85% of CF patients)
- also indicated for patients with other CFTR mutations responsive to elexacaftor based on clinical and/or in vitro data
Contraindications
- strong CYP3A4 inhibitors (use with dose reduction per labeling)
- hypersensitivity
Adverse Effects
Common
- headache
- upper respiratory tract infection
- abdominal pain
- diarrhea
- rash
- elevated transaminases
Serious
- hepatotoxicity (including serious elevation of transaminases)
- cataracts (in pediatric patients)
- neuropsychiatric events (insomnia, mood changes)
- elevated blood pressure
Pharmacokinetics (ADME)
| Absorption | oral; administer with fat-containing food; elexacaftor and tezacaftor peak at 6 hours; ivacaftor peaks at 4 hours |
| Distribution | all three components highly protein bound (>99%); large Vd |
| Metabolism | all three components are CYP3A4 substrates; extensive hepatic metabolism |
| Excretion | primarily fecal as metabolites |
| Half-life | elexacaftor: 24 hours; tezacaftor: 14.5 hours; ivacaftor: 12 hours |
| Onset | sweat chloride reduction within 2 weeks; FEV1 improvement over 2-8 weeks |
| Peak | 4-6 hours depending on component |
| Duration | morning dose (elexacaftor/tezacaftor/ivacaftor) + evening dose (ivacaftor alone) — twice daily |
| Protein Binding | >99% |
| Vd | extensive for all three components |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| strong CYP3A4 inhibitors (ketoconazole, itraconazole, clarithromycin) | markedly increase exposure to all three components; reduce to 2 morning tablets twice weekly (no evening dose) | major |
| strong CYP3A4 inducers (rifampin, carbamazepine, phenobarbital, St. John's wort) | dramatically reduce exposure to all three components; avoid combination | major |
| sensitive CYP3A substrates (cyclosporine, tacrolimus, sirolimus) | Trikafta inhibits CYP3A; monitor levels of sensitive CYP3A substrates carefully | moderate |
Nursing Considerations
- Administer morning dose (containing all 3 components) and evening dose (ivacaftor alone) with fat-containing food to maximize absorption of all components; standard dosing is 2 tablets in the morning and 1 tablet in the evening for adults and adolescents.
- Monitor liver function tests monthly for the first 3 months, quarterly for the first year, then annually; suspend if ALT or AST exceeds 5 times ULN; permanently discontinue if accompanied by bilirubin elevation suggesting hepatic injury.
- Monitor pediatric patients annually for lens opacities (cataracts); counsel families about this risk and schedule baseline ophthalmologic examination before starting therapy.
- Trikafta is a transformational therapy in CF; set realistic expectations that patients will experience significant improvements in lung function, weight, respiratory symptoms, and quality of life — but therapy is lifelong and adherence is critical.
Clinical Pearls
- Trikafta (elexacaftor-tezacaftor-ivacaftor) represents the most significant advance in cystic fibrosis therapy since the disease was described; in clinical trials it improved FEV1 by approximately 14%, reduced exacerbations by approximately 63%, and dramatically improved sweat chloride — with benefits maintained over years.
- Trikafta addresses the underlying molecular defect in approximately 85-90% of CF patients carrying at least one F508del allele; it does not cure CF (CFTR-mediated chloride transport remains subnormal) but transforms CF from a lethal disease of short life expectancy to a manageable chronic condition.
Safety Profile
Pregnancy use-with-caution
Lactation insufficient-data
Renal Adjustment Not required
Hepatic Adjustment Required
TDM Not required
Guideline Update pending
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.