Researchers at the University of Western Ontario announced Tuesday that they are beginning clinical trials next month for the first HIV vaccine being developed in Canada, using a groundbreaking technique that relies on the entire virus.
Preliminary toxicology tests show that the vaccine, SAV001, can produce strong immune responses, said the team lead by Dr. Chil-Yong Kang, a professor of virology at UWO's medical school.
The vaccine is still at an early stage of development. The U.S. Food and Drug Administration approved clinical trials, with Phase I ensuring that the vaccine isn't dangerous for patients, to begin with 40 HIV-positive volunteers in January.
"This is a highly significant milestone," Dr. Kang said in an interview, explaining that it brought his research closer to the hope of finding a way to inoculate humankind against the virus linked to AIDS.
The first phase of clinical trials will take a year. Phase II and III to test the vaccine's impact on immune responses and its efficacy will take another four years.
The SAV001 vaccine has been developed for the subtype B of HIV, the strain common in Europe, Australia and the Americas.
"If this works, we can customize it for other regions of the world," Dr. Kang said.
Until now, other experimental vaccines either used subunits of the virus or relied on genetically modified non-HIV viruses to carry an HIV-like genetic sequence.
"The thinking had been that it can be dangerous to use HIV itself, even if it's inactivated. Because if you don't inactivate all of it, you've got a problem," Alan Bernstein, former executive director of the Global HIV Vaccine Enterprise, said in an interview.
Dr. Kang's team instead is using a genetically modified whole virus that has been made inactive by chemicals and radiations.
He said his team focused on using a whole dead HIV because experimental vaccines developed with viral subunits have so far been unsuccessful.
"Whole virus vaccines work for polio, flu, rabies, Hepatitis B . . . they work, so we believe that on retroviruses like HIV it may have a good chance to be successful."
The SAV001-H vaccine has already been tested on monkeys and rats with no side effects.
"This is a very different approach from what's being used by other people. We need a diversity of approaches," Dr. Bernstein said.
Success remains elusive so far in the global effort to produce an HIV vaccine. Only one experimental vaccine, tested in Thailand two years ago, has been shown to improve immune responses in humans, and only with modest results.
Vaccines work by pre-arming the body against infections, making it easier for the patient to produce protective proteins called antibodies.
Developing an HIV vaccine has been challenging because it is a highly mutable virus, making it hard to find antibodies that can broadly neutralize the different strains of HIV.
The UWO project is a joint venture between the university and the South Korean biotech company Sumagen Co. Ltd., which has secured patents for the SAV001 vaccine.
About 34 million people across the globe were infected with HIV as of 2010, the World Health Organization estimates.
"This is an exceptionally rich time in HIV vaccine research. There are a lot of very important and exciting strategies being explored. And this is one of them," Dr. Bernstein said.