New Vaccine trials

Science Daily (November 27, 2008)

Phase I Clinical Trial To Test Combination Of Two HIV Vaccine Candidates Starts In London

The International AIDS Vaccine Initiative (IAVI) and the St. Stephen’s AIDS Trust at the Chelsea and Westminster Hospital have initiated a Phase I clinical trial in London, UK to test a prime-boost combination of two HIV vaccine candidates.

“Prevention is crucial in the fight against HIV and AIDS, and a vaccine is one of the most powerful prevention tools we know to combat infectious diseases,” said Professor Brian Gazzard, Research Director at the St. Stephen’s AIDS Trust and the principle investigator of this trial. “We hope this trial will contribute to a better understanding of how to induce with a vaccine an immune response to protect against HIV infection and AIDS.”

The news follows promising results recently announced by IAVI and partners for one of the two vaccine candidates to be tested, the MVA-based TBC-M4, which in a recent phase I trial generated modest immune responses in all volunteers who received the highest dose. According to Patricia Fast, Chief Medical Officer at the International AIDS Vaccine Initiative, “The responses observed with this vaccine candidate warrant further research to improve immune activation. We have learned from other studies that a prime-boost regimen has the potential to achieve just this.”

That is why the new trial will include a DNA-based vaccine candidate called ADVAX to prime the immune system. Previous Phase I studies with different DNA and MVA-based HIV vaccines in combination have shown that this prime-boost regimen was safe and well tolerated, and also able to generate enhanced immune responses when compared with the responses generated by either vaccine alone. The ADVAX vaccine candidate also offers economic value; it is relatively easy and cheap to manufacture, which makes it particularly appealing for use in the developing world.

A separate Phase I trial testing ADVAX and the MVA-based candidates in a prime-boost regime is planned for India. This trial would use a different mode of administration for the priming vaccine, different dosages and different vaccine regimens. Collectively, the results of both trials will help determine whether further development of both AIDS vaccine candidates in a prime-boost combination is warranted.

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