By Randall Osborne

In its second label expansion for Pulmozyme, an aerosol cystic fibrosis treatment, Genentech Inc. won approval from the FDA to market the drug for use by patients under five years old.

Pulmozyme originally was cleared for mild to moderate cystic fibrosis cases. In 1996, it was approved by the FDA for advanced cases. Until now, however, its use has been restricted to patients at least five years old. (See BioWorld Today, Dec. 3, 1996, p. 2.)

"This is similar, in that Pulmozyme is approved for a new, very specific population," said Betsy Rosenberg, spokeswoman for South San Francisco-based Genentech.

Revenue from sales of Pulmozyme, which is recombinant human DNase, rose by 32 percent during the last quarter of 1997 to $23.8 million. That was part of a 15 percent gain for the year, which ended with Pulmozyme revenues at $66.3 million.

About 3,000 patients with cystic fibrosis in the U.S. are under five years old, Rosenberg said.

"Pulmozyme is widely distributed and the price varies per distribution source and treatment regimen," she added, but the average cost is about $12,000 per year.

Cystic fibrosis is an inherited lung disorder caused by a faulty gene. It leads to thickened secretions of mucous, which can bring about persistent bacterial infection and congestion. "When inhaled, [the drug] acts like molecular scissors, cutting up the excess [mucous]," she said.

Because experience is limited in administering Pulmozyme to younger children, the company advised the drug be considered only for those under-five patients who may improve pulmonary function or reduce their risk of respiratory tract infection.

Genentech has evaluated the safety of Pulmozyme over two weeks in 98 patients from three months to 10 years old. Those not able to use the nebulizer mouthpiece were fitted with a nebulizing face mask.

Adverse reactions in the under-five patients were similar to those seen in older patients with mild to moderate disease: voice alteration, pharyngitis, laryngitis, rash, chest pain and conjunctivitis. Coughs were more common in the very young patients compared with those five to 10 years old.

Genentech's stock (NASDAQ:GNE) closed Monday at $67.812, up $0.375. *