Merck abandons HIV vaccine trials
26 September, 2007 | 2 comments | Category: thinking...
Out of the 39.5 million total people living with AIDS 24.7 million were in Africa at the end of 2006. Even though I am too skeptical to look past disparities in the politics of medicine, strides in science offer no fleeting consolation…
This is the BBC article documenting the Merck decision:
“International drug company Merck has halted trials on an HIV vaccine that was regarded as one of the most promising in the fight against Aids.
Merck stopped testing the vaccine after it was judged to be ineffective. In trials, the vaccine failed to prevent HIV infections among volunteers who were at risk of catching the virus, including gay men and sex workers.
Merck had previously expressed high hopes for the drug, which it spent 10 years developing.
‘Headed for failure’
Merck’s international trial, called Step, began in 2004 and involved 3,000 HIV-negative volunteers from diverse backgrounds, between the ages of 18 and 45.
Merck said that 24 of 741 volunteers who got the vaccine became infected with HIV, the virus that causes Aids. Out of a group of 762 volunteers who were given a dummy version of the jab, 21 became infected with HIV.
An independent monitoring panel recommended discontinuing the vaccination of volunteers, saying the trial was headed for failure. Most of the volunteers were at high risk of HIV infection. They were repeatedly given advice about how to practise safe sex, according to Merck.
The vaccine contained a common cold virus loaded with copies of three HIV genes. The hope was that exposure to the genes would prompt an immune response in the body so that cells containing HIV virus would be recognised and destroyed.
“Today is a very sad day for the industry because Merck’s vaccine had shown an ability to turn on the immune system, which gave many people optimism it would work,” said Sarah Alexander, from the HIV Vaccine Trials Network.
Doctors have said a preventative vaccine would be the best way to control the spread of HIV.”
Trails started in South Africa
early article about how the vaccine was projected to work and all…
ABC’s report on the Merck decision
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2 comments to “Merck abandons HIV vaccine trials”
Fausto Intilla, October 17th, 2007 at 7:25 pm:
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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
http://www.oloscience.com
Dinich, April 30th, 2009 at 3:17 pm:
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I never never trust those drug companies.
They are under a lot of pressure to make HIV/AIDS medication cheaper because the vast majority of HIV/AIDS patients are in Africa and other developing countries around the world. Those people can’t afford to buy those medications and that is what kills the motivation of these drug companies to work on finding a solution.
At the end of the day, these companies’ existence is determined by the money they make. They are under a lot of political and moral pressure to provide medications they produce to african countries for free or a cheap price. Something is missing in the whole picture. May be government funding, I dunno.
Right now, no one seems to have the incentive to solve this problem except the poor countries and of course organization like WHO, who don’t really have much power to do anything.
The Research facilities, the money, the expertise etc…are in the hands of those big companies. Unfortunately, the motivations seems to be missing.
God help us