The US Food and Drug Administration has approved the first drug to treat a genetic cause of cystic fibrosis (CF), the agency announced yesterday (January 31). The drug, Vertex’s Kalydeco, was granted approval in approximately 3 months, twice as fast as normal FDA priority reviews and one of the fastest FDA approvals ever, according to a Vertex press release. It is one of the first drugs approved to correct a specific genetic defect.
CF, the most common fatal genetic disease in the Caucasian population, is caused by defective or missing CFTR proteins, cell receptors that regulate ion and water transport in and out of cells. Lack of CFTR proteins results in the buildup of a thick, sticky mucus in the lungs. Kalydeco, a twice-a-day pill, is approved for use in people with the G551D mutation in the CFTR gene. Approximately 1,200 people in the United States, or 4 percent of those with CF, have the G551D mutation.
"Kalydeco is an excellent example of the promise of personalized medicine—targeted drugs that treat patients with a specific genetic makeup," FDA Commissioner Margaret Hamburg said in an FDA press release.
“Even though this drug isn’t for the majority of people, it proves that you can look at the mistake in the genes and design a drug in a rational way that will fix the problem,” Drucy Borowitz, director of the cystic fibrosis program at the State University of New York at Buffalo, told the Associated Press.
In two phase III trials involving 213 patients with the G551D mutation, the drug resulted in significant and sustained improvements in lung function. It is not effective in patients with other CFTR mutations, including F508, the most common CFTR mutation that results in CF.
Kalydeco, which begins shipping to pharmacies this week, will cost patients $294,000 per year, reported FierceBiotech, which is typical for a drug targeting a small disease population such as this. Vertex will provide Kalydeco for free to those who do not have insurance and have an annual household income of $150,000 or less, the company said.