FDA Approves Trikafta for Cystic Fibrosis in Children Ages 2-5

Key Takeaways

• FDA approved Trikafta for cystic fibrosis patients aged 2-5 years on April 26, 2023, based on NCT04537793 Phase 3 data (PubMed)
• Trial showed mean sweat chloride reduction of 57.9 mmol/L and lung clearance index improvement of 0.83 units at Week 24
• Weight-based dosing: 14+ kg receive 50% adult dose; under 14 kg receive 40% adult dose
• Approximately 900 U.S. children in this age group became newly eligible for treatment
• Safety profile consistent with older age groups; elevated liver enzymes observed in 11% of participants

What Is Trikafta and How Does It Work?

Trikafta (elexacaftor/tezacaftor/ivacaftor) is a triple-combination CFTR modulator therapy developed by Vertex Pharmaceuticals. It addresses the underlying cause of cystic fibrosis rather than just managing symptoms.

The therapy combines two CFTR correctors—elexacaftor and tezacaftor—which improve processing and trafficking of the defective CFTR protein to the cell surface, with ivacaftor, a potentiator that enhances channel gating function. This triple mechanism targets the F508del mutation, the most common CFTR mutation present in approximately 90% of CF patients.

When Did the FDA Approve Trikafta for Young Children?

The FDA granted approval for Trikafta in children ages 2-5 years on April 26, 2023. This expanded the previous indication that covered patients aged 6 years and older.

The approval marked the first time a treatment targeting the underlying cause of cystic fibrosis became available to approximately 900 children in the 2-5 year age group in the United States. Prior to this approval, these children had no approved CFTR modulator therapy options.

What Did the Phase 3 Clinical Trial Show?

The approval was supported by a 24-week Phase 3 open-label study (NCT04537793) that enrolled 75 children aged 2-5 years with cystic fibrosis and at least one F508del allele. The study was conducted in two parts: a 15-day treatment period (Part A) followed by a 24-week treatment period (Part B).

Primary endpoints included safety, pharmacokinetics, and changes in sweat chloride concentration and lung clearance index (LCI2.5). Results published in PubMed showed:

Trikafta Phase 3 Efficacy Results in Children Ages 2-5

Endpoint	Result at Week 24	Clinical Significance
Sweat chloride	Mean decrease of 57.9 mmol/L (95% CI: -61.3 to -54.6)	Indicates restored CFTR function
Lung clearance index (LCI2.5)	Decrease of 0.83 units (95% CI: -1.01 to -0.66)	Reflects improved lung function
Safety profile	98.7% mild/moderate adverse events	Consistent with older age groups

How Is Trikafta Dosed in Pediatric Patients?

Trikafta dosing for children ages 2-5 is weight-based, administered orally with fat-containing food twice daily approximately 12 hours apart:

• Children weighing 14 kg or more: Morning dose of elexacaftor 100 mg/tezacaftor 50 mg/ivacaftor 75 mg; evening dose of ivacaftor 75 mg
• Children weighing under 14 kg: 40% of the adult dose

Pharmacokinetic analyses demonstrated that exposures to elexacaftor, tezacaftor, and ivacaftor in children aged 2-12 years were within the range observed in patients aged 12 years and older, supporting the selected dosing regimens.

What Is the Safety Profile in Young Children?

The safety profile of Trikafta in children ages 2-5 was consistent with that observed in older age groups. The most common adverse events were cough, fever, and rhinorrhea, which were predominantly mild to moderate in severity.

Elevated liver enzymes (transaminases) were observed in 11% of study participants. This finding underscores the importance of liver function monitoring in young children receiving Trikafta, particularly those with a history of liver enzyme abnormalities. The FDA label recommends frequent liver function testing during the first year of treatment.

What Is the Market Impact of This Approval?

The FDA Trikafta approval for the 2-5 year age group expanded the eligible U.S. patient population by approximately 900 children. This represents a significant portion of the cystic fibrosis market, as the F508del mutation is present in approximately 90% of CF patients.

Trikafta competes with other CFTR modulators including tezacaftor/ivacaftor (Symdeko) and ivacaftor (Kalydeco), though Trikafta's triple-combination mechanism provides superior efficacy for patients with at least one F508del mutation. The pediatric expansion reinforces Trikafta's position as the standard of care for eligible CF patients.

Frequently Asked Questions

Primary Sources

1. U.S. Food and Drug Administration. Trikafta prescribing information. Accessed 2026-04-08.
2. ClinicalTrials.gov. Study NCT04537793: Elexacaftor/Tezacaftor/Ivacaftor in Children 2-5 Years. Accessed 2026-04-08.
3. PubMed. Phase 3 trial of elexacaftor/tezacaftor/ivacaftor in children 2-5 years with cystic fibrosis. Accessed 2026-04-08.