FDA Approves New Drug for Cystic Fibrosis : Medicine: Genetically engineered substance, dornase alfa, is the first new treatment to emerge in 30 years and promises to improve quality of life.

People suffering from cystic fibrosis, an inherited lung disorder that affects about 30,000 Americans, soon will have access to new, genetically engineered drug treatment, the Food and Drug Administration announced Thursday.

The FDA said it has approved use of the drug dornase alfa, the first new treatment for cystic fibrosis symptoms in 30 years.

“Although this product is not a cure for cystic fibrosis, the clinical data show that it can make a real difference in the quality of life for many patients,” said FDA Commissioner David A. Kessler. “This is the first treatment that specifically improves lung function in cystic fibrosis patients.”

The drug, manufactured by San Francisco-based Genentech Inc., will be marketed under the trade name Pulmozyme. When used in conjunction with standard therapies in a six-month clinical trial, the drug reduced the risk of severe respiratory tract infections in 27% of the patients who participated and improved their lung functions.

“It is a very important milestone,” said Dr. Robert J. Beall, an executive vice president of the Cystic Fibrosis Foundation. “If we can reduce the infections, we should be able to reduce the lung destruction and if we reduce the lung destruction that ought to contribute to these patients’ increased survival.”

There is yet no scientific data, however, to prove that the drug could extend patients’ lives. The median survival age is now 29 years. Twenty-five years ago, it was 5 years.

The treatment does have some side effects, including inflammation of the throat, chest pain, voice alteration and laryngitis.

The drug is not for all people with cystic fibrosis. There was no attempt to test the drug’s safety and effectiveness in children under 5 or in patients with less than 40% breathing function. The drug was not tested to see if it would be safe and effective for more than a year.

When people have cystic fibrosis, thick mucous fills their lungs and airways, reducing their lung functions and triggering chronic lung infections. Respiratory complications are the major cause of death among patients.

Pulmozyme works by liquefying the thick mucous, making it easier to dislodge.

The Food and Drug Administration has approved several genetically engineered drugs over the last several years, including Interferon, to treat hepatitis and leukemia; G-CSF, to produce white blood cells for cancer patients receiving chemotherapy; GMCSF, to produce white cells for patients receiving bone marrow transplants, and Erythropoetin, to produce red blood cells for patients with kidney problems.

“We have approved a handful of drugs that are genetically engineered to treat conditions,” Dr. Jane Woodcock, a physician at the FDA said. “These proteins could not be administered any other way, so we really have a new kind of drug treatment. It is hoped that this is the promise of biotechnology.”

Genentech, a pioneer in the biotechnology field, has been researching genetically engineered drugs for 17 years and started marketing its first such drug, Protropin, a human growth hormone that is used in the treatment of children with stunted growth, in 1985. Pulmozyme will be the company’s third drug on the market. Other drugs it helped develop are marketed by other companies.