April 26, 2013
Clinical HIV Vaccine Study Terminated After Review Panel Finds Drug Ineffective
Brett Smith for redOrbit.com - Your Universe Online
The vaccine was intended to stimulate the immune system into preparing a defense against three sub-types of HIV. However, it instead showed a "non-statistically significant increase in HIV acquisition among volunteers in the investigational vaccine group compared to those in the placebo group," according to a statement released by vaccine-developer, the National Institute of Allergy and Infectious Diseases (NIAID).
The review panel found 41 HIV infections among the 1,250 study participants who got the experimental HVTN 505 vaccine and 30 infections among the 1,244 who received the placebo. All of the volunteers were said to be men or transgender people who have sex with men.
"This is quite a substantial disappointment," Dr. Scott Hammer, one of the trial's principal investigators, told the Los Angeles Times. "We´ve learned from every clinical efficacy trial we've done. We've had good and bad news, but each one takes us a little closer in terms of what to pursue and not to pursue."
In its statement, the NIAID noted those who contracted the virus were referred to local services "for appropriate care and treatment.”
The HVTN 505 trials were also considered a disappointment because the vaccine failed to shrink the viral load of volunteers who contracted HIV after they signed up for the trial.
"This trial has provided a clear, swift answer about a specific vaccine strategy. It's not the answer we hoped for, but the search doesn't end here," Mitchell Warren, executive director of the nonprofit group AVAC: Global Advocacy for HIV Prevention, said in a statement to Reuters. "Researchers need to unpack the data from this trial to understand more about why this strategy didn't prevent infection.”
The latest incident isn´t the first instance of a large HIV vaccine trial to end abruptly due to disappointing results. In 2003, a trial of the vaccine known as AIDSVAX was ended after it was found some who got it developed HIV.
However, promising results rose out of the ashes of that trial as a new formulation, called RV-144, was found to reduce infection rates by 30 percent in a Thailand-based clinical trial on heterosexual men in 2009.
The HVTN 505 vaccine was developed based on results from the RV-144 trial that showed how a vaccine could coach the immune system into recognizing and fighting both interior genetic material and the outer envelope of the virus.
Dr. Stephen J. Brown, medical director of the AIDS Research Alliance, told the LA Times researchers will be poring over two years' worth of blood samples from the Los Angeles site of the HVTN 505 trials.
According to the World Health Organization (WHO), 34 million people across the world are living with HIV, including 2.5 million who became infected in 2011, and over 25 million people have died since the epidemic began.
Reports say the next major set of HIV vaccine trials will start next year in southern Africa.