The quest for HIV vaccine has suffered yet another major setback. The National Institute of Allergy and Infectious Diseases (NIAIDA), part of the National Institutes of Health (NIH) scrapped a U.S. human trial dubbed PAVE 100, to test a HIV vaccine, saying that more research was needed before the vaccine could be tested on humans.
Following the decision to halt the trial of HIV vaccine candidate MRKAd5 or V520, dubbed STEP last September, researchers were doubtful about the future of the PAVE 100 trial. V520 altered the immune system, facilitating infection, rather than providing immunity against the HIV and failed to reduce viral load of the patients in the STEP trial.
The experimental vaccine to be tested in the PAVE 100 trial would also have used an adenovirus serotype 5 (Ad5) vector that is similar, though not identical, to the Ad5 vector used in the failed STEP trial.
However, the NIAID has not given up entirely on the PAVE 100 trial. It believes the vaccine is scientifically intriguing and sufficiently different from previously tested HIV vaccines. The NIAID is considering testing the experimental vaccine in a smaller, more focused clinical study. It will entertain a proposal for an alternative study with one specific goal: to determine if the vaccine regimen significantly lowers viral load.
With none of the clinical trials for HIV vaccine yielding positive results, some scientists and HIV research advocacy groups have been calling for the U.S government to suspend funds for testing existing experimental vaccines and re-allocate resources into effective, proven HIV/AIDS prevention, testing and treatment strategies.
The recent failures in HIV vaccine development clearly indicate that it still requires fundamental research to understand the basic biology of the AIDS virus and its effects on the human immune system.
No comments:
Post a Comment