Cystic Fibrosis Advance Shows Promise

Inexpensive Treatment Cuts Infections, Boosts Lung Function

Medically Reviewed by Louise Chang, MD on January 18, 2006
From the WebMD Archives

Jan. 18, 2006 -- The newest treatment for cystic fibrosis is a breath of fresh air for patients hoping to reduce flare-ups while saving money.

Unlike some other drugs used to treat this deadly lung disease, the new treatment is inexpensive. It's safe. It improves lung function. Most importantly, it cuts down on the flare-ups of the chronic infections that plague people with cystic fibrosis.

And that's just what it can do today. The treatment -- or an improved version of it -- might one day keep kids with cystic fibrosis from getting germ-filled mucus plugs in their lungs.

The treatment is called inhaled hypertonic saline. It's nothing fancy -- just a concentrated salt solution inhaled through a nebulizer. New clinical trials in Australia and in the U.S. show that the treatment works -- in a totally different way than previously expected. Cystic fibrosis is caused by an inherited genetic defect that allows mucus to collect in the lungs.

Researchers included Peter T.P. Bye, PhD, and Mark Elkins, MHSc, of the University of Sydney and Royal Prince Alfred Hospital, Sydney.

"Hypertonic saline is a new, effective therapy for cystic fibrosis," Elkins tells WebMD. "The benefits that can be anticipated are better lung function, fewer flare-ups of their lung infection, and a better quality of life."

Researchers for the U.S. study included Richard C. Boucher, MD, director of the cystic fibrosis research and treatment center at the University of North Carolina at Chapel Hill, and Scott H. Donaldson, MD, UNC assistant professor of pulmonary and critical care medicine.

"This is the first treatment aimed at a very early stage in cystic fibrosis disease," Donaldson tells WebMD. "It raises the possibility that early use may delay or prevent cystic fibrosis lung disease and add years of life to these patients."

The studies, and an accompanying editorial, appear in the Jan. 19 issue of The New England Journal of Medicine.

New Insights Into Cystic Fibrosis

Hypertonic saline isn't new. It's been used for decades to help people clear their airways. Why? It makes people cough.

That made doctors think hypertonic saline worked only as an irritant. Still, they thought it might help cystic fibrosis patients clear mucus from their lungs.

That idea was met with only partial success. Newer agents -- such as Pulmozyme, which actually thins mucus -- worked better. Hypertonic saline got shelved.

But cystic fibrosis researchers then made a breakthrough in basic science. They found that an extremely thin layer of water -- just a few hundred thousandths of an inch -- covers lung cells. This thin layer of water keeps mucus moving along. But people with cystic fibrosis don't have this layer of water. Instead of moving away, mucus sticks to their lung cells.

That made the U.S. and Australian researchers take a second look at hypertonic saline. The salt solution, they reasoned, might not be an irritant at all. Instead, the salt might draw water to the surface of cystic fibrosis lung cells, loosening up the sticky mucus.

As it turns out, this seems to be the case.

"These studies show that hydration of the lung surface is the way to go in cystic fibrosis," Boucher tells WebMD. "This was surprisingly effective. It makes sense to make this the base therapy for cystic fibrosis lung disease. If you restore mucus clearance, all the bacteria in the cystic fibrosis lung are in that mucus."

Bacteria are the source of the chronic infections that cause cystic fibrosis flare-ups. Getting rid of some of these germ-filled wads of mucus should mean fewer flare-ups. And that's exactly what happened.

Patients treated with hypertonic saline in the Australian study had 56% fewer flare-ups than those treated with an inactive placebo. Seventy-six percent of the treated patients -- but only 62% of the placebo patients -- were free of flare-ups during the yearlong study.

The patients' lung function improved, too. But that improvement was relatively modest, notes the editorial by Felix Ratjen, MD, PhD, head of respiratory medicine at Toronto's Sick Kids Hospital.

"The effect on lung function isn't all that impressive, but the hypertonic saline improves long-term mucus clearance by making more liquid available on the airway surface," Ratjen tells WebMD. "If there is clearance of mucus from the lower respiratory tract, this may result in less severe infections and lower frequency of infections."

The Real Goal: Treating Infants

What really excites cystic fibrosis researchers is the possibility that very young children might be able to use hypertonic saline. Why? There's the chance that the treatment could keep kids with cystic fibrosis from getting germ-filled mucus plugs in the first place.

"I think younger patients are going to be key," Ratjen says. "If you have established mucus deep in your lungs, in these areas already plugged by mucus there will be no effect of treatment. But if you start treatment in infancy, that would be a different story. You could potentially have a much more pronounced effect on cystic fibrosis lung disease."

Tests are already under way.

"We are already testing the safety and efficacy of inhaled hypertonic saline in 4- and 5-year-olds," Donaldson says. "And we have a plan to start testing in infants, newborns, and 1- to 2-year-olds. The idea is to stop them from getting mucus plugs, rather than have the infectious cascade happen."

Not an Easy Treatment

Hypertonic saline has its limitations. It's certainly no cure for cystic fibrosis. Patients can only inhale the salty mist so far into their lungs, leaving deep mucus plugs untouched.

The saline solution used is usually about 7% salt. Human blood is only 1% salt. The Atlantic Ocean is 4% salt, while the Dead Sea is 12% salt. At first, patients have a hard time getting used to the treatment.

"The first time you inhale it you feel like you are drowning," Boucher says. "Patients really do mobilize secretions, so they get a funny feeling in the chest. It is different. It is different tasting, a different sensation, but the lung will feel different, too."

The stuff tastes terrible, Ratjen says. And treatment takes a long time -- 15 minutes, twice a day at least. Still, only about one in 20 patients finds it intolerable. Most patients get used to it, and some can tolerate even more-concentrated salt solutions.

In fact, Boucher says, "patients love it." Once they've been on the treatment for a while, he says, they don't want to enroll in clinical trials that don't guarantee hypertonic saline treatment.

And hypertonic saline may not be the best way to restore the lung's protective layer of water. Researchers are experimenting with a powdered sugar compound that tastes better -- and would reach deeper into the lungs. And there's hope that in the future, science may find a drug that restores surface water to cystic fibrosis lung cells.

Show Sources

SOURCES: Elkins, M.R. The New England Journal of Medicine, Jan. 19, 2006; vol 354: pp 229-240. Donaldson, S.H. The New England Journal of Medicine, Jan. 19, 2006; vol 354: pp 241-250. Ratjen, F. The New England Journal of Medicine, Jan. 19, 2006; vol 354: pp 291-293. Richard C. Boucher, MD, professor and director, cystic fibrosis research and treatment center, University of North Carolina, Chapel Hill. Scott H. Donaldson, MD, assistant professor of pulmonary and critical care medicine, University of North Carolina, Chapel Hill. Mark Elkins, MHSc, University of Sydney and Royal Prince Alfred Hospital, Sydney, Australia. Felix Ratjen, MD, PhD, head of respiratory medicine, Sick Kids Hospital; professor, University of Toronto, Ontario, Canada.
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