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Second Stage of HIV Vaccine Trial Begins In London and Oxford

April 04, 2002

A new phase of the world`s first clinical trial to test a vaccine candidate for one of the most prevalent HIV strains affecting Africa starts today (Thursday 4 April 2002) in London and Oxford. This expands the ongoing trials in Oxford and Nairobi which aim to harness the ability of the body`s own immune system to fight disease. The first volunteers on the London arm of the trial were vaccinated today.

Volunteers are randomised into groups, which will receive various combinations of the two vaccine components or a placebo at differing intervals. This is predominantly a safety study but the information collected may help establish optimum dosage, how many booster injections to give and a vaccination schedule. All of this information will contribute to the eventual evaluation of the vaccine`s effectiveness.

Professor Jonathan Weber of Imperial College of Science, Technology and Medicine, London is leading the team that will co-ordinate the London end of the trial, from St Mary`s Hospital, Paddington. They will collaborate with colleagues led by Professor Andrew McMichael, honorary director of the Medical Research Council Human Immunology Unit in Oxford, (MRC HIU). The teams need to recruit 120 volunteers in total from the London and Oxford regions. They must be between the ages of 18 and 60, HIV negative and at low risk of HIV infection and able to attend 12 appointments over the course of a year.

The International Aids Vaccine Initiative (IAVI) is funding the trial. This research is part of the larger initiative to develop a simple, effective and affordable HIV vaccine, which is the basis of the unparalleled partnership between IAVI, the MRC HIU and the University of Nairobi, Kenya. Imperial College will play an important role in this phase of the UK trials.

The vaccine has two parts, one to prime the immune system and one to boost it. The DNA (prime) component contains genetic information about the virus to prime the immune system and provoke an immune response. The body is tricked into defending itself against the virus before it is there. The aim is to give the body a head start in fending the virus off to stop it overpowering the immune system and taking hold. An MVA (modified vaccinia ankara) booster, which contains the same genetic information and has a powerful ability to stimulate the killer T-cells, is used to keep the immune system responding.

Genetic information about the Clade A HIV-1 virus, one of the commonest strains in Eastern Africa, is contained within the vaccine. There is no live HIV material so participants are not at risk of infection.

Professor Jonathan Weber said: "Timing and dosage of vaccines is crucial to the overall success of a trial such as this. It will help establish whether the vaccine works and what procedures should be in place for healthcare programmes. I`m sure the people of London will respond to our need for volunteers - it`s a chance to help us save lives."

Professor Andrew McMichael said: "We`re pleased with the progress we are making with the trials, but there`s still a lot of work to do. There`s a strong sense of joint purpose between the team in Oxford, colleagues at the University of Nairobi and International Aids Vaccine Initiative (IAVI) about what we`re trying to achieve. It`s great to have the expertise of the London team on board as well."

Seth Berkley, President and Chief Executive of IAVI said: "These trials are a significant step in IAVI`s objective to fast-track a diverse portfolio of AIDS vaccines in human testing. We raise a hand to salute progress on the vaccines being tested in Oxford and London, while moving forward on other fronts to meet the research challenges yet remaining."

Extensive studies of sex workers in Nairobi and elsewhere gave the clues that helped in the design of the vaccine. Despite frequent exposure to HIV, a small minority of these women has resisted infection over many years.

Professor J. J. Bwayo, who is chairman of the Department of Medical Microbiology at the University of Nairobi and Principal Investigator of the Trial said: "These women make an immune response which the vaccine is trying to emulate. Further trials will help us determine if the vaccine can stimulate the same strong cellular immune response to HIV that we have seen in these women."

The start of the trial was also welcomed by Derek Bodell, Chief Executive of the National Aids Trust who said: "The trial is an important step towards the development of a safe and effective HIV vaccine. NAT particularly welcomes the development of vaccines specifically designed for use in Africa. NAT believes that UK vaccine development should prioritise vaccines that will work to combat HIV in highly affected countries. Globally we need to strengthen prevention education efforts while at the same time giving priority to developing new prevention tools such as vaccines."

Anyone in London or Oxford who is eligible and interested in joining the trial can call:

London: Ken Legg, Miranda Cowen or Dr Nicky Mackie on 0800 587 4406
Oxford: Mary Brooks or Dr Inese Cebere on 0800 169 6978

Imperial College, University of London