A team of researchers at Western University developing a preventative HIV vaccine announced the successful completion of the first phase of human trials Sept. 3.
The vaccine, SAV001-H, has been in development by Chil-Yong Kang, a virology professor in the department of microbiology and immunology, and his team at the Schulich School of Medicine and Dentistry for the past 10 years.
First phase trials had HIV-positive individuals injected with genetically modified and inactive HIV of the subtype most prevalent in North America, Western Europe and Australia, and showed no adverse side effects, according to Kang.
He said recipients actually had a “boosted immune response” to the injections.
“It is a proven technology for vaccination,” Kang said, noting it is the same method used to combat polio and influenza. This strategy involves injecting patients with dead HIV to trigger an immune response.
Kang said previous attempts of this method have faced two major problems.
“Virus replication is somewhat slow so you cannot produce adequate quantities to make a vaccine,” he said. “Secondly, it is too dangerous to produce large quantities of HIV in any setting.”
The team solved these problems through genetic modification of the HIV genome, specifically a part involved in rapid reproduction of the virus, according to Kang.
After being milled and purified, he said this enhanced HIV was then killed using chemicals and a round of radiation, before being injected in the form of a vaccine. Kang said this allows the body to produce antigens against HIV without being at risk of disease, and if a recipient is exposed in the future they will be protected.
The next step, phase two of human trials, will see Kang’s team test SAV001-H on individuals without HIV, he said.
While Kang said he is optimistic, Jonathan Angel, president of the Canadian Association for HIV Research said he believes it is too early to tell how successful the vaccine will be.
“The degree to which it generates a potentially effective immune response remains to be clarified,” Angel said.
He said successful completion of the first phase of humans trials only shows that the vaccine is safe.
At the end of 2011, an estimated 71,300 people were living with HIV in Canada, according to the Canadian government. Approximately 3,000 of these people were newly infected, an 11.4 per cent increase from 2008.
High-risk groups include men who have sex with men, injection drug users, hemophiliacs, and sex workers, according to the government.
There are over 34 million HIV-positive individuals worldwide, many in developing countries, according to the UN.
This raises the question of whether SAV001-H, which specifically targets a subtype common in Canada, can be modified for global use. Kang said there is encouraging news from other HIV researchers that the antibodies will be able to cross-neutralize other subtypes.
He said another option is to customize the vaccine for different regions of the world.
Kang said his team has been developing a therapeutic HIV vaccine to cure previously infected individuals. He said they are currently in the stage of animal testing but “preliminary results are very, very promising.”
