Age 2 years to less than 6 years old

Study 6

Study 6 was a 24-week study in which the safety of KALYDECO was evaluated in 34 children age 2 years to less than 6 years old with cystic fibrosis (CF). All children in this study took KALYDECO. No one in this study took placebo. The primary purpose of this study was to determine the safety and tolerability of KALYDECO.


Mutations eligible to enroll in this study were:

G1244E, G1349D, G178R, G551D, G551S, G970R,* S1251N, S1255P, S549N, S549R.

*KALYDECO is not indicated for people with CF who have the G970R mutation.


Mutations included in this study:

32 children had the G551D mutation and 2 had the S549N mutation.


How KALYDECO was given

Children who weighed less than 31 pounds (14 kg) received 50 mg of KALYDECO oral granules every 12 hours.

Children who weighed 31 pounds (14 kg) or more received 75 mg of KALYDECO oral granules every 12 hours.

All children took KALYDECO oral granules mixed with 1 teaspoon of soft food or liquid every 12 hours with fat-containing food.

Learn how to give your child KALYDECO oral granules.


Study results


The type and frequency of side effects for children in the study were similar to those seen in KALYDECO studies with people with CF age 6 years and older.

High liver enzymes were more common in children who had abnormal liver enzymes before starting KALYDECO.

See additional safety information.


Other study results

Sweat chloride

After taking KALYDECO: 
Sweat chloride decreased on average by -45 mmol/L at Week 24. 

Sweat chloride is the amount of salt in your child’s sweat. A decrease in sweat chloride levels does not mean there will be an improvement in lung function (FEV1). 

Because no one in this study took placebo, it is not known if changes in sweat chloride were due to KALYDECO.


Study limitations

KALYDECO was approved in people age 2 years to less than 6 years old based on the benefits shown in studies of KALYDECO in older people as well as the safety assessment in this study.

Talk to your healthcare provider to learn more about how KALYDECO was approved in this age group.

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