FDA Approves Ivacaftor for Eligible Infants Ages 1 Month and Older With Cystic Fibrosis

FDA officials have approved ivacaftor (Kalydeco, Vertex) for use in children with cystic fibrosis (CF) ages 1 month to less than 4 years of age who have at least 1 mutation in their CF transmembrane conductance regulator (CFTR) gene that is responsive to ivacaftor based on clinical or in vitro assay data.¹

Ivacaftor is already approved for the treatment of CF in patients ages 4 months and older. It was first approved in the United States in 2012 and is now the first and only CFTR modulator approved for infants as young as 1 month of age.¹

“Treating the underlying cause of cystic fibrosis as early as possible is important, and this approval, the first for a CFTR modulator in this age group, means families will now have a medicine for eligible infants,” said Carmen Bozic, MD, executive vice president of Global Medicines Development and Medical Affairs and chief medical officer at Vertex, in a press release.¹

In some individuals with certain types of mutations in the CFTR gene, the CFTR protein at the cell surface does not function properly. As a CFTR potentiator, ivacaftor is an oral medication designed to facilitate the ability of CFTR proteins to transport salt and water across the cell membrane, which hydrates and helps clear mucus from the airways. It was the first medicine to treat the underlying cause of CF in individuals with specific mutations in the CFTR gene.¹

CF is a rare, life-shortening genetic disease affecting more than 88,000 patients globally. It is a progressive, multi-organ disease affecting the lungs, liver, pancreas, gastrointestinal tract, sweat glands, and reproductive tract, and it is caused by the defective or missing CFTR protein resulting from mutations in the CFTR gene.¹

Children with CF must inherit 2 defective CFTR genes, 1 from each parent. Although there are many different types of CFTR mutations that can cause CF, the vast majority of patients with this diagnosis have at least 1 F508del mutation. In the lungs, the defective or missing CFTR protein leads to buildup of abnormally thick, sticky mucus, as well as chronic lung infections and progressive damage that eventually leads to death for many patients. The median age of death for individuals with CF is in the early 30s.¹

The new FDA approval was supported by a cohort in the phase 3, 24-week, open-label study evaluating the safety, pharmacokinetics, and pharmacodynamics of ivacaftor in individuals with CF who are less than 24 months of age and have an ivacaftor-responsive CFTR mutation. The cohort demonstrates a safety profile similar to that observed in older children and adults.¹

In the cohort of individuals aged 4 months to less than 6 months, investigators found a mean absolute change from baseline in sweat chloride of -50.0 mmol/L, which was a secondary endpoint. Although there was no direct correlation between decrease in sweat chloride levels and improvement in lung function, researchers do know that individuals with CF have higher levels of chloride in their sweat because chloride is unable to move in or out of the body’s cells.²

Subjects in this trial received ivacaftor every 12 hours with fat-containing food, in addition to their prescribed therapies for CF. In the 4- to <6-months cohort, patients received 25 mg oral granules until reaching 6 months of age, after which they could receive 50 mg oral granules if they weighed 7 kg or more.²

“As a physician caring for infants and children with cystic fibrosis, I see the importance of initiating therapies early in life that may slow disease progression,” Margaret Rosenfeld, MD, MPH, one of the principal investigators for the Kalydeco study in children less than 24 months old, said in a press release. “Today’s approval provides many families and caregivers comfort in knowing that there is a highly effective modulator therapy available for their babies with [CF].”¹

REFERENCES

1. Vertex Announces US FDA Approval for Kalydeco (ivacaftor) to Treat Eligible Infants With CF Ages 1 Month and Older. News release. Vertex Pharmaceuticals. May 3, 2023. Accessed May 4, 2023. https://news.vrtx.com/news-releases/news-release-details/vertex-announces-us-fda-approval-kalydecor-ivacaftor-treat
2. Kalydeco. Clinical Trials for Ages 4 Months to <2 Years. Accessed May 4, 2023. https://www.kalydecohcp.com/trial-8#primary-endpoint