Wednesday, September 08, 2010

HIV vaccine research

Keith Alcorn for Aidsmap (8 September 2010)

Where is HIV vaccine research heading?

Global HIV Vaccine Enterprise sets out road map for next five years

Following last year’s positive result from an HIV vaccine trial in Thailand the Global HIV Vaccine Enterprise has issued a new scientific plan, calling for a speeded-up effort to test new vaccine candidates in large trials.

Global HIV Vaccine Enterprise executive director Dr Alan Bernstein also called for young scientists to get involved in the field of HIV vaccine research.

The plan, available for download at the Global HIV Vaccine Enterprise website, outlines two key priorities:

· better integration of the latest information from basic science and ongoing trials into new vaccine studies,

· and better use of information from preclinical studies and from other areas of scientific research.

Aidsmap.com spoke to Dr Alan Bernstein, about some of the priorities in the HIV vaccine field.

Following the failure of the adenovirus-based HIV vaccine developed by Merck in 2008, there has been considerable debate about the future of HIV vaccine research, with some pronouncing the field a dead-end, and others calling for a back-to-basics approach to investigating how HIV interacts with the immune system.

But the Global HIV Vaccine Enterprise says that as well as more laboratory science, more trials in humans are needed if we are to answer the fundamental questions still puzzling vaccine researchers.

One example of the sort of question that needs to be answered is:

· which immune system changes after vaccination correlate with protection against HIV,

· and do these changes indicate a mechanism by which the immune system protects against HIV infection that can be exploited in future vaccine development?

The Thai trial of a two-vaccine regimen that reduced the risk of HIV infection by 31% is still being analyzed to determine what can be learnt about the correlates of protection, with laboratories all over the world currently examining samples provided by the trial sponsors.

Dr Bernstein is hopeful that the pipeline of promising candidate vaccines will soon offer some serious follow-up candidates to the vaccines tested in the Thai trial and the STEP and Phambili trials, but larger trials of promising candidates need to get underway more quickly.

“We need to go from one phase 2b study every seven years to something like one every year, so that we have the opportunity to incorporate new findings into the design of studies.”

The Global HIV Vaccine Enterprise calls this process “integrating iterative scientific enquiry with product development.”

This means quickly incorporating new information from ongoing studies or failed studies into the design of new studies and trials that are just getting underway. It also means sharing data more quickly and testing a wider variety of vaccine approaches sooner in human efficacy trials.

“Trials are expensive – phase III trials cost at least $120 million over their lifetime. [Starting one each year] implies a ten to fifty-fold increase in funding. So if there’s another breakthrough like the Thai trial we may need more than a 50% increase in funding.”

However Dr Bernstein declined to say how much the Global HIV Vaccine Enterprise needs in order to fully realize its plans.

The Global HIV Vaccine Enterprise is also seeking to mobilize new financial resources, and new research capacity.

Responding to perceptions outside the HIV field that a vaccine for the infection is impossible, Dr Bernstein said: “It’s as likely that there will be a vaccine for HIV as drugs for Alzheimer’s or some types of cancers. There are sound reasons to believe that we can get a vaccine.”

But the development of successful vaccines is likely to depend on the renewal of the research workforce too. Dr Bernstein says that the HIV vaccine field needs young scientists who have the ambition to make a career in this area.

The HIV Vaccine Enterprise also wants to catalyze interest in solving some of the problems inherent in making an HIV vaccine by reaching out to other fields, such as systems biology and genomics.

There is a need to use computation and new developments in networks theory to understand the relationships between millions of fragments of information derived from studying vaccine responses, and the interactions between HIV and the immune system.

New technologies also need to be exploited in the search for a vaccine.

“There’s good reason to think mucosal immunity is critical in HIV transmission, but how do we monitor what’s going on in the mucosa without invasive and impractical tissue sampling? Is there a non-invasive way to imaging at the mucosal surface to tell us what’s going on during the very earliest stages of infection? There’s been a revolution in imaging technology and we should talking to the [imaging experts].”

Link to the Global HIV Vaccine Enterprise website

Link to the Aidsmap article

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