A study to investigate the safety of Kaftrio® in 2 to 5 year olds with CF (VX20-445-111)


CTAP badge
Therapeutic approach
Restore CFTR Function
Trial status
Closed with results Participating Centres
Trials Tracker ID
Last updated

Full title

A Phase 3 Study Evaluating the Safety, Tolerability, and Pharmacokinetics of Kaftrio® in children with cystic fibrosis 2 to 5 years old

Study details

This study is to learn more about the safety of taking Kaftrio® (elexacaftor in combination with tezacaftor and ivacaftor) and how well it works in 2- to 5-year-olds with CF. All three of the medicines which make up Kaftrio® are called CFTR modulators. CFTR modulators help the faulty CFTR protein to function properly.

Everyone in the study will receive the study medications. Study participants will be asked to visit the CF clinic around 8 times over 6 months (24 weeks), with an additional follow-up visit approximately 4 weeks after finishing the study medications. During these visits, the research team will look at how the study medications are affecting overall health as well as specific assessments to check lung, pancreas and kidney functions. Bloods and other samples will be collected at some of the visits.

Study results

This study looked at the safety and effectiveness of Kaftrio in children aged 2-5 with at least one F508del gene variant. 

18 children took part in the first part of the study and received the treatment for 15 days. 74 children then completed the second part of the study and received the treatment for 24 weeks. 

Treatment was generally safe and well tolerated. The treatment led to significant improvements in lung function and CFTR function (measured using sweat tests). BMI remained stable. 

These results are consistent with previous studies in older age groups and support the use of Kaftrio in children as young as 2 years old. 

Phase 3
Length of participation
7 months (28 weeks)
Recruitment target
CF sponsor
Vertex Pharmaceuticals Incorporated
CF sponsor type

Who can take part?

Age range
2 to 5 years
Including people

2 to 5 years old

Homozygous for the F508del mutation or heterozygous for F508del and a minimal function (MF) mutation (F/F or F/MF genotypes)

Excluding people

Clinically significant cirrhosis with or without portal hypertension

Lung infection with organisms associated with a more rapid decline in pulmonary status

Solid organ or hematological transplantation

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CF centres running this trial


Liverpool - Alder Hey Children's Hospital

CTAP centre
NHS Trust
Alder Hey Children's NHS Foundation Trust
Eaton Road
West Derby
L12 2AP
Local site investigator
Rebecca Thursfield
Trial Coordinators
Victoria King

Royal Brompton Hospital (London) - Paediatrics

CTAP centre
NHS Trust
Guy's and St Thomas' NHS Foundation Trust
Royal Brompton Hospital
Sydney Street
Local site investigator
Jane Davies
Trial Coordinators
[email protected]