Drug Found to Slow Demise of Boys With Muscular Dystrophy
A Brazilian scientist has found a drug that appears to slow the deterioration that typifies Duchenne muscular dystrophy, an invariably fatal disease that afflicts about 20,000 boys in the United States at any one time.
However, there is a catch: The drug has the unwanted effect of stunting the growth of children who receive it.
Nevertheless, a committee of scientists attending the International Congress on Neuromuscular Diseases in Los Angeles at the Century Plaza voted unanimously Tuesday to begin testing the drug as soon as possible on several dozen patients in the United States, according to Neil J. Lewis, associate director of research for the Muscular Dystrophy Assn.
“It’s a battle against time,” said Mayana Zatz, associate professor of genetics at the University of Sao Paulo. “If we can add time, the patients can have a chance for better drugs that will come along.”
Zatz is one of more than 1,000 scientists attending the five-day conference.
The drug, mazindol, is an appetite suppressant for obese people who want to lose weight. It is unknown why diminishing growth hormone in growing boys with Duchenne muscular dystrophy appears to slow progression of the disease.
Five years ago Zatz noted that a Duchenne patient named Silvio, one of the nine dystrophic boys in an extended family she was studying, was far more agile at age 13 than his younger similarly afflicted cousins and brothers.
The fact that Silvio was a dwarf--his height was that of a 4-year-old--struck Zatz as a possible explanation for the fact that he could still run and climb stairs, while the other boys were confined to wheelchairs before his age. She wondered if a deficit of growth hormone was responsible for Silvio’s relative agility.
A year ago, Zatz had the opportunity to explore the possibility, after a pair of 7 1/2-year-old identical twins, Martin and Robert, were diagnosed with Duchenne muscular dystrophy.
A typical Duchenne patient begins a very rapid decline in muscle function at about age 7, according to Zatz. The fact that the twins were genetically identical meant that a study could be designed in which the boys differed only in the type of treatment they received.
Physicians at the University of Sao Paulo medical center decided to give one twin a drug that reduces the amount of growth hormone that his body releases and the other twin a placebo--a sugar pill that produces no physiological effect. The researchers did not know which twin received which.
“After one year, the twin who received the drug was in better condition,” Zatz said in an interview. “What we saw was a slowing down--but not an arrest--of the steady muscular deterioration that typifies the disease.”
Zatz is scheduled to present the results of the 12-month experiment today.
Twin Deteriorates
At the start of the study, both twins could climb stairs, run at the same speed and performed similarly in other muscular tests. After one year, Martin, the twin who received the drug, could still do these things, Zatz said. However, Robert could not climb stairs any longer, and he took longer to run a proscribed distance and do similar exercises.
When the study ended and the answer was learned, Robert was immediately placed on the medication, she said.
At the end of the study, Robert had grown about 1 1/2 inches and Martin had grown less than half an inch.
Despite the drug’s growth retarding effect, Zatz said she feels “guilty” about not learning earlier in the study that the drug was responsible for slowing muscle deterioration so that Robert could have begun treatment earlier. However, she said, mazindol does not totally suppress the growth hormone.
Encouraged by the results, the Sao Paulo team several months ago began a larger study involving 16 Duchenne boys. She said that in the 16 years she has been studying muscular dystrophy families in Brazil, many patients have said that they would be willing to risk a drug trial if it meant that they might live another year or two.
