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FDA Advisers Recommend Approval of First-Ever Inhaled Antibiotic To Treat Cystic Fibrosis

November 21, 1997

FDA Advisers Recommend Approval of First-Ever Inhaled Antibiotic To Treat Cystic Fibrosis PatientsBy LAURAN NEERGAARD

BETHESDA, Md. (AP) _ Cystic fibrosis patients may soon be able to breathe a potent antibiotic directly into their lungs to fight off deadly infection.

Advisers to the Food and Drug Administration recommended approval of the first inhaled antibiotic Friday. The drug Tobi, tobramycin for inhalation, appeared to increase the lung function of cystic fibrosis patients up to 12 percent after six months of treatment, said the manufacturer, PathoGenesis Corp.

The company couldn’t say how long the improvement will last, or if patients actually might live a little longer. But in a disease so lethal that most patients die before age 30, specialists told the FDA panel that even a modest improvement could be life-changing.

``To feel better is something patients with cystic fibrosis dream about,″ said Robert Beall, president of the Cystic Fibrosis Foundation. Patients were clamoring for the inhaler, he said.

The FDA’s advisers unanimously recommended approval of Tobi, but said PathoGenesis must continue tracking patients to determine if long-term use is effective _ and to answer lingering questions about side effects and drug resistance that may develop in continuous users.

The FDA is not bound by its advisers’ recommendations, but usually follows them.

About 30,000 Americans have cystic fibrosis, an incurable genetic disease. Most patients die of lung failure as thick, sticky mucus clogs their airways and traps bacteria that cause infection.

Particularly dangerous is Pseudomonas aeruginosa, a bacterium that afflicts 80 percent of CF patients by adulthood _ and that increases their risk of death by eight times.

Intravenous tobramycin, usually given in the hospital, is the top treatment for Pseudomonas flareups. But even the best patients lose 1 percent to 2 percent of lung function every year, and doctors can’t give higher, more effective doses because the drug’s path through the bloodstream can severely damage the kidneys and cause deafness.

So doctors hunted ways to get tobramycin straight into the lungs, allowing higher doses right where the bacteria live.

In two studies of some 500 patients, PathoGenesis said people inhaling tobramycin saw their lung function improve up to 12 percent while patients given dummy pills got worse. Tobi patients were 26 percent less likely to be hospitalized. When the amount of bacteria in their phlegm was measured, 85 percent had no bacterial growth or some decrease.

The FDA, however, used more conservative statistics to argue that Tobi patients’ lungs really improved just 6 percent. Still, the agency acknowledged an effect, and said it may be greatest in young children.

Patients didn’t suffer the hearing loss so worrisome in IV tobramycin users, but 3 percent got tinnitus, a ringing in the ears. FDA scientists questioned if that was an early warning of future hearing loss, and the advisory panel told PathoGenesis to do more hearing tests to find out.

A bigger question is whether chronic antibiotic inhalation will cause the bacteria to mutate into untreatable strains. Some Tobi patients did have a few more bacteria in their phlegm even though they felt better, suggesting the possibility of some early drug resistance. But the FDA advisers concluded the changes were minor, and called instead for long-term monitoring to catch drug resistance.

An estimated 3,000 to 5,000 CF patients already are trying to inhale antibiotics, as desperate doctors on their own mix up IV solutions and put them into inhalation devices. But those IV solutions contain preservatives that PathoGenesis said are dangerous to lung tissue. Dr. Preston Campbell III, head of the Cystic Fibrosis Foundation’s nationwide care centers, said Tobi is the only inhaled antibiotic studied for both effectiveness and safety, and called for quick FDA approval so those patients could switch to a proven drug.

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