A drug developed by pediatric researchers at UC San Diego School of Medicine has been successful in treating cystinosis, a rare and often fatal kidney disease, according to a study published today in the New England Journal of Medicine.
In the study, conducted over the last eight years, 93 children with cystinosis were treated with oral doses of cysteamine. The results indicated that the drug slowed down the degeneration of the children's kidneys and improved growth, the researchers reported.
"Getting it published in the New England Journal of Medicine is sort of the 'Good Housekeeping seal of approval,' " said Dr. Jerry Schneider, a UCSD professor of pediatrics, who said he knew last summer that the drug worked. " . . . We think (publication) will make it easier to move on to the next stages."
Those stages include developing a more palatable form of the drug, which Schneider said has a foul smell and tastes like rotten eggs. Researchers in this country are testing a less offensive form of the drug, and Swiss food chemists have combined the drug with a chicken broth mixture.
Schneider, coordinator of national efforts to diagnose and treat children with cystinosis, said he also hopes that publication of the successful results of the study will bring into the program new patients who had been reluctant to try an unproven drug.
Cystinosis is a hereditary disease, diagnosed currently in some 300 children in the United States. It causes crystals of the amino acid cystine to accumulate in the eye, bone marrow, lymph nodes, white blood cells and internal organs.
Cystinotic children appear normal at birth. But their growth becomes retarded and they develop kidney problems by the age of six to nine months. At the average age of 9 years, they suffer from kidney failure. Many also experience severe sensitivity to sunlight, necessitating sunglasses even on cloudy days.
Kidney dialysis and transplants can delay the progress of the disease, but there is no permanent cure.
In the study, done in collaboration with the National Institute of Child Health and Human Development and the University of Michigan, the 93 children receiving cysteamine were compared with 55 children in a historical control group who did not receive the drug.
According to Schneider, most of the patients on the drug are "doing very well," tolerating the drug with their kidneys functioning well. In contrast, patients who have undergone dialysis or transplant have suffered vision and neurological problems in their late teens or 20s because of the continued buildup of cystine crystals.
100 Children on Drug
Schneider said there are currently 100 families in the United States with children on the drug.
"I think there are a lot of cases not so much unreported as undiagnosed," Schneider said Wednesday. "It's obviously a very rare disease. There are probably more cases than we know about."
According to Schneider, who pioneered the studies of the use of cysteamine on cystinosis, the drug had been used in experiments previously to protect against radiation. He said radiologists have expressed interest in the drug as a possible way of protecting normal tissue during radiation therapy for cancer.
He said the same drug is also used in England as an antidote for overdoses of Tylenol.