Vertex Kalydeco for Cystic Fibrosis Approved by FDA Ahead of Schedule
The US Food and Drug Administration has approved Kalydeco (ivacaftor) for the treatment of a rare form of cystic fibrosis (CF) under its priority review program. The agency reviewed and approved the drug ahead of the April 18th goal date. It is designated as an orphan drug, which identifies the disease as affecting fewer than 200,000 people in the US, but early clinical study results suggest that the drug could potentially be used in combination with another to help 90% of people with the fatal disease – or possibly up to 27,000 in the United States alone.
Cystic Fibrosis is a serious genetic disorder affecting the lungs and other organs that ultimately leads to an early death. It affects about 30,000 in the United States and is the most common fatal genetic disease in the Caucasian population.
CF is caused by a mutation in a gene that encodes for a protein called CFTR that regulates ion and water transport in the body. The dysfunctional process then results in the formation of a thick mucus that builds up in the lungs, digestive tract and other parts of the body leading to severe respiratory and digestive problems as well as other complications such as infections and diabetes.
About 4% of CF patients, or about 1200 people, have a specific mutation in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene known as G551D. It is this population that Kaleydeco is designed to treat. The new drug, taken twice a day by patients aged six and older, helps the protein made by the CFTR gene function better and, as a result, improves lung function and other aspects of CF such as increasing weight gain.
Positive results in two 48-week placebo-controlled clinical studies helped the FDA to speed up approval time down from a standard of 10 months. In these trials, treatment with Kalydeco resulted in significant and sustained improvement in lung function. The most common side effects were upper respiratory tract infection, headache, stomach ache, rash, diarrhea, and dizziness.
“Kalydeco is the first available treatment that targets the defective CFTR protein, which is the underlying cause of cystic fibrosis,” said Janet Woodcock, M.D., director of the FDA’s Center for Drug Evaluation and Research. “This is a breakthrough therapy for the cystic fibrosis community because current therapies only treat the symptoms of this genetic disease.”
Unfortunately, Kalydeco will not help CF patients who have two copies of the F508 mutation in the CFTR gene, which is the most common of the more than 1,800 genetic mutations that cause the disease. However, Vertex Pharmaceuticals has another experimental drug in the works called VX-809 which can increase delivery of CFTR to the cell surface, the process that is defective in those with F508 mutations.
“Our work is not done,” said Vertex CEO Jeffrey Leiden MD PhD.
Kalydeco was discovered as part of a collaboration between Vertex and Cystic Fibrosis Foundation Therapeutics, the nonprofit drug discovery and development affiliate of the Cystic Fibrosis Foundation. FDA Commissioner Margaret A. Hamburg MD calls Kalydeco “an excellent example of the promise of personalized medicine.” It is a “breakthrough therapy for the CF community because current therapies only treat the symptoms of this genetic disease,” adds Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research.
Source: US Food and Drug Administration
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