Age 6 months to less than 1 year old

Study 8

The safety and tolerability of KALYDECO were evaluated in 43 children age 1 month 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 1 year to less than 2 years old.

Mutations eligible to enroll in this part of the study were:

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

Mutations included in this part of the study:

10 children had the G551D, and 1 had the G178R mutation.

How KALYDECO was given

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

All children took KALYDECO oral granules mixed with 1 teaspoon of an age-appropriate soft food or liquid every 12 hours with fat-containing food. All children continued to take their other CF treatments.

Learn how to give your loved one 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.

(average mmol/L beginning of study was 101.5)

Sweat chloride is a measure of the amount of salt in a person'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.

*FEV1=forced expiratory volume, or how much air a person can exhale in a forced breath in 1 second.

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 people age 6 years and older, 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.


Before taking KALYDECO, tell your doctor about all of your medical conditions, including if you:

  • have liver or kidney problems
  • are allergic to KALYDECO or any ingredients in KALYDECO. See the Patient Information for a list of ingredients
  • 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

What is KALYDECO® (ivacaftor)?


KALYDECO is a prescription medicine used for the treatment of cystic fibrosis (CF) in people aged 1 month and older who have at least one mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) 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 1 month of age.

Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

KALYDECO may affect the way other medicines work, and other medicines may affect how KALYDECO works. Ask your doctor or pharmacist for a list of these medicines if you are not sure.

Especially tell your doctor if you take:

  • the antibiotics rifampin (RIFAMATE®, RIFATER®) or rifabutin (MYCOBUTIN®)
  • seizure medicines such as phenobarbital, carbamazepine (TEGRETOL®, CARBATROL®, EQUETRO®), or phenytoin (DILANTIN®, PHENYTEK®)
  • St. John’s wort
  • antifungal medicines such as ketoconazole, itraconazole (SPORANOX®), posaconazole (NOXAFIL®), voriconazole (VFEND®), or fluconazole (DIFLUCAN®)
  • antibiotics such as telithromycin, clarithromycin (BIAXIN®), or erythromycin (ERY-TAB®)

What should I avoid while taking KALYDECO?

  • KALYDECO can cause dizziness in some people who take it. If you experience dizziness, do not drive or operate machines until symptoms improve
  • Avoid food or drink containing grapefruit while you are taking KALYDECO

What are the possible side effects of KALYDECO?

KALYDECO can cause serious side effects, including:

  • High liver enzymes in the blood, which have happened in people 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 people who have had high liver enzymes in the past, your 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
  • Serious allergic reactions have happened to people who are treated with KALYDECO. Call your healthcare provider or go to the emergency room right away if you have symptoms of an allergic reaction. Symptoms of an allergic reaction may include:
  • rash or hives
  • tightness of the chest or throat or difficulty breathing
  • light-headedness or dizziness
  • Abnormality of the eye lens (cataract), which has happened in some children and adolescents receiving KALYDECO. Your doctor should perform eye examinations before 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.

Use of KALYDECO in children aged 1 month to less than 6 months born from a pregnancy lasting (gestational age) less than 37 weeks has not been evaluated.

Call your doctor for medical advice about side effects. You may 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.