Monday, October 1, 2007

HIV vaccine trial fails

HIV vaccine trial, which was being conducted worldwide including Malawi, has been halted after Data Safety Monitoring Board (DSMB), the body that was responsible for the monitoring the progress of the project, discovered that the vaccine was not effective. John Hopkins Project, an institution responsible for the project in Malawi confirmed.

John Hopkins Project Director Dr Newton Kumwenda said DSMB met on September 18, 2007 to review results of the interim efficacy analysis they concluded that the study will not meet its efficacy objectives and recommended that trial being stopped.

On a report posted on September 21,2007 on Merck website—A United States of America pharmaceutical company that was producing the vaccine— announced that the vaccine did not meet its objective and failed to prevent infection.
However, Dr Kumwenda said the latest findings of the vaccine efficacy failure would not affect Malawi participants as the institution did not enroll new volunteers for more than 2 years.

About eight Malawians were injected with a vaccine, HVTN 050, Merck V20-018 vaccine—that contains three HIV genes—in a Phase I, whose objective was to establish the safety and immunogenecity of the vaccine.

“The HIV Vaccine trial being conducted in Malawi is a Phase I safety and immunogenecity trial. The HIV vaccine candidates although similar, the two trials are different.

“Although the data for this finding is specifically from the STEP V520-023 trial , all study sites involved in similar Merck/HVTN vaccine program are advised to cease administering trial vaccine but to continue all other study follow-up procedures,” he said.

JHP spokesperson Fatima Zulu said the organization will continue monitoring the health of the eight Malawian participants as per agreements until the time that was agreed upon expires.
“We will continue monitoring them because we know that some of the side effects would take a long time to come out,” she said.

On Merck website, however, the company indicated that volunteers who had received at least two vaccinations and who were HIV negative for at least the first 12 weeks of the trial, 19 cases of HIV infection were observed in the 672 volunteers who received vaccine and 11 cases were observed in the 691 volunteers who received placebo. 

"In addition, the vaccine did not reduce the amount of virus in the bloodstream of those who became infected; HIV RNA levels approximately 8 to 12 weeks after diagnosis of infection were similar in the vaccine and the placebo arms.  The geometric means of the HIV RNA levels in the blood of infected individuals, the standard measure of ongoing HIV replication, were approximately 40,000 copies/mL in the vaccine group and approximately 37,000 copies/mL in the placebo group,” the website said.

Merck & Co., Inc. is a global research-driven pharmaceutical company dedicated to putting patients first.  Established in 1891, Merck currently discovers, develops, manufactures and markets vaccines and medicines to address unmet medical needs. 
The Company devotes extensive efforts to increase access to medicines through far-reaching programs that not only donate Merck medicines but help deliver them to the people who need them.  Merck also publishes unbiased health information as a not-for-profit service

1 comment:

Fausto Intilla (fisico teorico) said...


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