Age 6 months to less than 1 year old

Study 8

The safety and tolerability of KALYDECO were evaluated in 36 children age 4 months to less than 2 years old with cystic fibrosis (CF). All the children in this study took KALYDECO.

One part of the study evaluated 11 children age 6 months to less than 1 year old.

See the results for children age 4 months to less than 6 months old and 1 year to less than 2 years old.

Mutations eligible to enroll in this study were:

G1244E, G1349D, G178R, G551D, G551S, R117H, S1251N, S1255P, S549N, S549R.

How KALYDECO was given

Children who weighed 15 pounds (7 kg) to less than 31 pounds (14 kg) received 50 mg of KALYDECO oral granules every 12 hours.

In the clinical study, instruction was provided to give the dose of KALYDECO oral granules mixed into 1 teaspoon of an age-appropriate soft food or liquid, either orally with a syringe or with a spoon, every 12 hours along with a fat-containing food. 

Direction was given to ensure the full contents of the syringe were administered.

KALYDECO granules should not be given with a bottle.

Please note: A 25-mg dose is available for children who weigh 11 pounds (5 kg) to less than 15 pounds (7 kg).

Learn how to give your child KALYDECO oral granules.

Study results


The safety of KALYDECO, observed in this study, was similar to what was observed in KALYDECO studies in people with CF age 2 years and older.

See additional safety information.

Other study results

Sweat chloride

For children age 6 months to less than 1 year old who took KALYDECO:
Sweat chloride decreased on average by -58.6 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 6 months to less than 1 year old based on the efficacy 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.

Important Safety Information

Do not take KALYDECO if you take certain medicines or herbal supplements, such as:

  • the antibiotics rifampin (RIFAMATE®, RIFATER®) or rifabutin (MYCOBUTIN®)
  • seizure medicines such as phenobarbital, carbamazepine (TEGRETOL®, CARBATROL®, and EQUETRO®), or phenytoin (DILANTIN®, PHENYTEK®)
  • St. John’s wort

Talk to your doctor before taking KALYDECO if you take any of the medicines or supplements listed above.

What is KALYDECO® (ivacaftor)?


KALYDECO is a prescription medicine used for the treatment of cystic fibrosis (CF) in patients age 4 months and older who have at least one mutation in their CF gene that is responsive to KALYDECO.

Talk to your doctor to learn if you have an indicated CF gene mutation.

It is not known if KALYDECO is safe and effective in children under 4 months of age.

What should I tell my doctor before taking KALYDECO?

Before you take KALYDECO, tell your doctor if you:

  • have liver or kidney problems
  • drink grapefruit juice or eat grapefruit
  • are pregnant or plan to become pregnant. It is not known if KALYDECO will harm your unborn baby. You and your doctor should decide if you will take KALYDECO while you are pregnant
  • are breastfeeding or planning to breastfeed. It is not known if KALYDECO passes into your breast milk. You and your doctor should decide if you will take KALYDECO while you are breastfeeding

KALYDECO may affect the way other medicines work, and other medicines may affect how KALYDECO works.

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements, as the dose of KALYDECO may need to be adjusted when taken with certain medications.

Especially tell your doctor if you take:

  • antifungal medications such as ketoconazole (e.g., NIZORAL®), itraconazole (e.g., SPORANOX®), posaconazole (e.g., NOXAFIL®), voriconazole (e.g., VFEND®), or fluconazole (e.g., DIFLUCAN®)
  • antibiotics such as telithromycin (e.g., KETEK®), clarithromycin (e.g., BIAXIN®), or erythromycin (e.g., ERY-TAB®)

What should I avoid while taking KALYDECO?

  • KALYDECO can cause dizziness in some people who take it. Do not drive a car, use machinery, or do anything that needs you to be alert until you know how KALYDECO affects you
  • You should avoid food containing grapefruit while you are taking KALYDECO

What are the possible side effects of KALYDECO?

KALYDECO can cause serious side effects.

High liver enzymes in the blood have been reported in patients receiving KALYDECO. Your doctor will do blood tests to check your liver:

  • before you start KALYDECO
  • every 3 months during your first year of taking KALYDECO
  • every year while you are taking KALYDECO

For patients who have had high liver enzymes in the past, the doctor may do blood tests to check the liver more often.

Call your doctor right away if you have any of the following symptoms of liver problems:

  • pain or discomfort in the upper right stomach (abdominal) area
  • yellowing of your skin or the white part of your eyes
  • loss of appetite
  • nausea or vomiting
  • dark, amber-colored urine

Abnormality of the eye lens (cataract) has been noted in some children and adolescents receiving KALYDECO. Your doctor should perform eye examinations prior to and during treatment with KALYDECO to look for cataracts.

The most common side effects of KALYDECO include:

  • headache
  • upper respiratory tract infection (common cold), including sore throat, nasal or sinus congestion, runny nose
  • stomach (abdominal) pain
  • diarrhea
  • rash
  • nausea
  • dizziness

Tell your doctor if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of KALYDECO. For more information, ask your doctor or pharmacist.

Call your doctor for medical advice about side effects. You are encouraged to report side effects to FDA at 1-800-FDA-1088.

For further information, please see full Prescribing Information, including Patient Information.

People with CF pictured may or may not be taking KALYDECO.