Cystic Fibrosis Drug Combo: How Effective Is It?
One medication seems to partly counteract the other, suggests study on human cells
"Existing medications target only the symptoms of cystic fibrosis but not the cause of the disease," Gentzsch said. "As a result, they may lead to improvement but do not prevent the overall slow progression of lung disease over time. In addition, many current therapies are time-consuming and can be more difficult to use in young children."
A newer drug known by the brand name Kalydeco targets a protein that doesn't work properly in certain people with cystic fibrosis. Researchers have praised the medication, but it only works in an estimated 5 percent of patients who have a specific genetic variation.
The big question is whether Kalydeco and a drug that's in development known as lumacaftor might provide a one-two punch to treat the wide majority of cystic fibrosis patients. If the combo worked, as some short-term studies have suggested, "the hope would be that disease progression would be slowed and that patients would live longer, healthier lives," Gentzsch said.
But the new study raises doubts. The researchers tested the drugs on epithelial cells, which are found in much of the body, and found evidence that Kalydeco actually reverses some of the effects of lumacaftor. "This is consistent with results reported from recent clinical trials that showed meaningful but modest improvements in lung function in patients treated with this drug combination," Gentzsch said.
Scientists believe Kalydeco helps water escape cells so it can moisten mucus, while lumacaftor paves the way for liquid to get where it's supposed to go. But the study suggests Kalydeco disables some of lumacaftor's effects.
Gentzsch said other medications and other combinations of treatments could indeed benefit patients. Future research into how they affect specific types of patients could lead to more insight into whether they're worthwhile treatments, she said.
The study by Gentzsch and colleagues appears in the July 23 issue of Science Translational Medicine. It was funded by the U.S. National Institutes of Health, the Cystic Fibrosis Foundation, and the Else Kroner-Fresenius Foundation.