The study had the mundane name of Merck V520-023, but the hopes attached to the drug being tested were anything but ordinary.
So when clinical trials of a prototype AIDS vaccine were abruptly halted in September, many around the world were disheartened.
The only thing that could make this news worse is if it is allowed to slow efforts toward finding a vaccine for this awful disease.
Last week, researchers gathered in Seattle for a three-day conference to try to figure out what went awry with the vaccine, which may actually have put volunteers at greater risk for contracting HIV. Questions were many and answers were few.
An independent oversight committee recommended stopping the trial, which began in late 2004 and involved volunteers from around the world, because the vaccine didn’t appear to be working. It didn’t prevent participants from getting HIV or reduce the severity of infection among those who became ill during the trial.
“The data are disappointing and puzzling, but we don’t have definitive answers,” said Dr. Lawrence Corey, lead scientist for the HIV Vaccine Trials Network, which conducted the trial with pharmeceutical giant Merck & Co.
The trial was supposed to involve 3,000 uninfected volunteers and go through at least next year. But only 1,500 were involved when problems were detected.
Participants had been injected with either a vaccine or a placebo. The vaccine was designed to stimulate the body’s immune system to produce a strong T-cell response, which researchers hoped would enable uninfected people to fight off HIV.
As researchers looked at the numbers more closely, they began to notice that those who had gotten the vaccine seemed to be getting infected with HIV at higher rates than the placebo group.
It could be that the vaccine was causing illness, it could be coincidence, or it could be linked to other factors, such as participants’ sexual habits.
Those conducting the trial were advised to stop injecting participants but to continue monitoring them.
One issue that researchers face is whether to tell participants what they received in the trial — the vaccine or the placebo. The health of participants ought to be the top concern in this decision.
HIV is a pandemic, and each day another 12,000 people become infected. Since the early 1980s, AIDS has claimed 25 million lives.
In science, as in life, failure can be a teacher. We surely hope medical researchers and those who fund them redouble their efforts in the face of the disappointment over this vaccine.
