2006年VOA标准英语-Human Trials of New Drugs Carry Risks for

By Jane M Friedman
Washington, D.C.
02 May 2006
 
watch Clinical Trial report
 

Human Trials, preparing for the shot  
  
Six Londoners almost died recently during a human trial of a new drug.  The British government reacted by announcing it will convene 1 an international panel to consider stricter rules for drug trials. Those trials continue in the United States and other western nations in the search for a bird flu vaccine 2.

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When a virus is deadly enough to kill birds and humans who come into direct contact with them, testing a vaccine against bird flu can be complicated, and potentially dangerous.

But American researchers, fearing a global pandemic, are testing experimental vaccines 3 on human subjects.  More than 700 Americans have taken a vaccine that researchers hope will protect against the bird flu virus should it mutate and spread among humans. So far, the vaccine has been safe, if not easily mass produced.   

Dr. Anthony Fauci (file photo)  
  
Dr. Anthony Fauci is head of infectious diseases at the U.S. National Institutes of Health, which is funding the trials.  "The good news is that you can induce an immunity 4 that would be protective. The sobering news is that the dosage that is required to get to that level of immunity is prohibitively high, so we're confronted with an important challenge."

Human trials of new drugs are always full of unknowns. In the 1970s, a U.S. trial of a swine flu vaccine killed several volunteers and caused paralysis 5 in hundreds of others.

Six years ago, at the University of Pennsylvania, a teenager died during a trial of a new gene 6 therapy.  The U.S. government stopped the trial.  But at congressional hearings afterward 7, Paul Gelsinger, the boy's father, demanded strict regulation to screen out volunteers whose health could be put at risk by experimental drugs. 

Paul Gelsinger   
  
"I am not against gene therapy,” said Mr. Gelsinger. “I recognize it holds so much promise for so many people. But we cannot allow what happened to Jesse to happen again."

In March, British relatives waited outside a London hospital to hear if their loved ones would survive a trial of an immune-boosting drug. The six men made it, but say the American company running the trial didn't tell them about serious side effects.  

Dr. Fauci remarked, "There are adverse 8 events associated with any intervention 9 you give.  Hopefully the adverse events are, A, not serious and, B, they occur very rarely"

Human trials in the third world have come under special scrutiny 10 from public interest groups that say drug companies frequently ignore international standards when they test new drugs in poorer nations.

 
Dr. Peter Lurie
  
Dr. Peter Lurie is a deputy director of the watchdog group Public Citizen, which is calling for stricter controls on tests in Africa and elsewhere.  "Probably the best known example of this is a series of studies that were planned in the last century in which HIV positive pregnant women were randomized to sometimes get active drug to prevent transmission of HIV from themselves to their infants, but a large fraction of the women got nothing at all ... That kind of stuff would be completely unacceptable in the United States."

U.S. officials respond by saying that overseas trials benefit people in countries where the diseases being researched are endemic.

As bird flu trials enter a second phase, researchers are testing a vaccine reinforced with minerals, called adjuvants, so that a smaller dose can deliver greater protection. At several universities, scientists are trying out the vaccine on elderly people to see if they too will be protected.

Dr. Fauci says a bird flu vaccine is not yet within view. "It is difficult to say how long that would take.  It will depend on so many factors, but it will not happen in the next month or so. This is something that will take years to get where we want to be."

For volunteers in the bird flu trials, the worst part is over.  But future trials of new vaccines, for example, against HIV AIDS, will carry risks for the thousands of volunteers a trial requires. And drug companies will have to balance their desire to go to market with the need to protect their human volunteers.