BOSTON (Reuters) - The drug voriconazole is more effective than an older drug at treating a lethal fungus infection that strikes transplant recipients, cancer patients and others with weak immune systems, researchers said Wednesday.

Voriconazole, sold under the brand name Vfend by Pfizer Inc., was at least partially successful at fighting invasive aspergillosis in 53 percent of volunteers.

In contrast, the older drug, amphotericin B, worked in only 32 percent of people suffering from the fungal infection.

The study, published in Thursday's New England Journal of Medicine, found that 42 percent of the 133 amphotericin recipients were dead after 12 weeks of treatment.

The death rate was 29 percent among the 144 patients who got voriconazole.

The study was financed by Pfizer and carried out by a research team led by Raoul Herbrecht of Hautepierre Hospital in Strasbourg, France.

The team found that the newer drug also generated fewer side effects such as chills or fever. However, temporary vision problems, including blurred vision, altered color perception and hypersensitivity to light, appeared in nearly 45 percent of the voriconazole recipients.

Thirteen voriconazole recipients experienced confusion or hallucinations, against five who were given amphotericin B, which is made by at least two companies.

The U.S. Food and Drug Administration approved the use of voriconazole for aspergillosis last May.

Copyright 2002, Reuters News Service