Kalydeco Side Effects May Increase Risk of Child Cataracts: FDA

Children taking the cystic fibrosis drug Kalydeco may face an increased risk of developing cataracts, according to federal drug regulators. 

The FDA issued a warning about the potential side effects of Kalydeco to the cystic fibrosis community on August 29, advising that a recent study appears to indicate that this new treatment, which was just approved this year, may cause clouding on the lenses of children’s eyes.

The regulatory agency is encouraging patients to continue with their treatment at this point, but is requiring the manufacturer to conduct additional clinical trials to assess the risks and benefits.

The study that led to this warning was conducted on juvenile rats, to see whether Kalydeco could be used to treat children under the age of two. Researchers found that cataracts formed in the eyes of juvenile rats treated with the drug between the ages of seven and 35 days. The amount of Kalydeco the rats were given was equivalent to giving a human child one-tenth the maximum daily recommended dosage. But human and rat eyes develop differently, leaving some uncertainty as to whether and how the phenomenon would occur in human children.

Vertex Pharmaceuticals, the manufacturer of Kalydeco, has been ordered to conduct additional studies on the development of cataracts in children under 11 years of age. The researchers will have to follow the patients for two years after treatment to assess the rate of cataract development.

New information about the potential risk of cataracts from Kalydeco side effects has also been added by the FDA to the medication guide and label warnings.

Kalydeco (ivacaftor) is currently approved for the treatment of cystic fibrosis who have a specific genetic mutation known as G551D. It is approved for use in patients age six and older.

Cystic fibrosis is a disease that causes mucus to form on internal organs. The mucus is thick and sticky and can interfere with their operation. In the lungs, it blocks airways and makes it hard to breathe, while on the pancreas it can prevent proper digestion. The side effects of the disease often dramatically shortens the lifespan.