aleqm5hzllcwsajjsztoczkxd79glbvzra.jpgJOHANNESBURG (AFP) — The supervisor of a major HIV vaccine trial in South Africa voiced “huge disappointment” Saturday after testing was halted in the wake of poor results from sister trials in Australia and the United States. US pharmaceutical giant Merck announced on Friday that it had halted the trials of its V520 vaccine after a study found it to be ineffective.

“It is a huge disappointment because this vaccine has shown promise all the way through, but it’s only when you get in on these big trials that you start to see how the vaccine behaves,” South Africa trials supervisor Glenda Gray told AFP. South Africa is home to nearly 5.5 million HIV-positive people. “Although in earlier studies we saw beautiful immune responses, it doesn’t look like this immune response translates into something that could protect people against HIV infection,” Gray added.

The prototype had been tested on 700 HIV-negative people since February in five South African hospitals. “It is devastating for us, to say the least, but we have to keep going … we need something that can prevent infection,” said Gray, who also heads AIDS research at the Chris Hani Hospital in Soweto, southwest Johannesburg. She stressed that the prototype did not have any consequence on the health of those who participated in the study.

“It is sad and… it is a huge disappointment because it is about life and prevention of new infection,” said Treatment Action Campaign (TAC) president Zachie Achmat, the main organisation that helps people living with AIDS in South Africa. “But it shows that there is proper control on human trials and when something is not effective it can be stopped,” said Achmat, adding, “we want to encourage them to maintain hope.”

Source: Google News & AFP

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  • I’m wondering if this is one of those “goverment paid off” halts…*hmm*

  • Source: http://www.sciencedaily.com/releases/2007/10/071012080135.htm

    Science Daily — The search for a vaccination against HIV has been in progress since 1984, with very little success. Traditional methods used for identifying potential cellular targets can be very costly and time-consuming.
    The key to creating a vaccination lies in knowing which parts of the pathogen to target with which antibodies. A new study by David Heckerman and colleagues from Massachusetts General Hospital, publishing in PLoS Computational Biology, has come up with a way to match pathogens to their antibodies.
    At the core of the human immune response is the train-to-kill mechanism in which specialized immune cells are sensitized to recognize small peptides from foreign pathogens (e.g., HIV). Following this sensitization, these cells are then activated to kill cells that display this same peptide. However, for sensitization and killing to occur, the pathogen peptide must be “paired up” with one of the infected person’s other specialized immune molecules–an HLA (human leukocyte antigen) molecule. The way in which pathogen peptides interact with these HLA molecules defines if and how an immune response will be generated.
    Heckerman’s model uses ELISpot assays to identify HLA-restricted epitopes, and which HLA alleles are responsible for which reactions towards which pathogens. The data generated about the immune response to pathogens fills in missing information from previous studies, and can be used to solve a variety of similar problems.
    The model was applied to data from donors with HIV, and made 12 correct predictions out of 16. This study, says David Heckerman, has “significant implications for the understanding of…vaccine development.” The statistical approach is unusual in the study of HLA molecules, and could lead the way to developing an HIV vaccine.
    Citation: Listgarten J, Frahm N, Kadie C, Brander C, Heckerman D (2007) A statistical framework for modeling HLA-dependent T cell response data. PLoS Comput Biol 3(10): e188. doi:10.1371/journal.pcbi.0030188
    Note: This story has been adapted from material provided by Public Library of Science.

    Fausto Intilla