A British Columbia-led research group is paving the way for a landmark preventative HIV medication it hopes can reduce Canada’s stagnant rates of new HIV infections.
Long-acting pre-exposure prophylaxis, or PrEP, is more than 99 per cent effective at preventing the development of HIV when it is injected every two months, according to clinical trial data reported by manufacturer ViiV Healthcare.
The injectable drug, cabotegravir, was approved by the U.S. Food and Drug Administration last December but has not yet been submitted to Health Canada for approval.
Currently, the injectable medication is approved to treat HIV among the nearly 63,000 Canadians estimated to live with the virus, but not to be used preventatively.
And while an oral form of PrEP has been available in Canada since 2016 and the United States since 2012, experts say increasing treatment options will be key to reducing the more than 1,500 estimated new infections in Canada each year.
“Where we are today is obviously a much better place than we’ve ever been,” said Michael Montess, a postdoctoral associate at Western University.
“But if you want to actually have those HIV numbers decrease, we’re going to want to find more innovative strategies and figure out how to make sure that they’re being as effective as possible.”
Long-acting injectable PrEP is lower-maintenance and improves adherence, the single most significant factor in the medication’s success at preventing HIV. Similar long-acting shots have been developed for contraceptive and psychiatric medications.
“Once you have that [PrEP] shot, you can know that you are almost 100 per cent covered for the next two months,” said Montess. “So you don’t have to worry about forgetting a pill or anticipating a possible exposure and timing it correctly. The shot really gives you a lot of flexibility and keeps adherence high.”
Montess, a former postdoc at the University of Victoria, is working with colleagues in British Columbia and Ontario to identify and reduce barriers to long-acting injectable PrEP before it becomes available.
The Future of PrEP is Now project, funded by the Canadian Institutes of Health Research, will also investigate challenges with oral PrEP to make both versions more easily accessible.
The same medication used for PrEP was first used to treat HIV, which is transmitted through blood, semen, rectal and vaginal fluids during sex and needle-sharing, and through breastmilk from parent to child.
The drug is antiretroviral and prevents HIV from multiplying enough to be transmitted or quickly advance illness in more than 95 per cent of people who take it, according to the Public Health Agency of Canada.
It is one of several milestone treatments developed since 1996 that mean being HIV-positive is no longer a certain sentence to dying of AIDS. AIDS has killed more than 40 million people worldwide and first began to infect Two-Spirit people and men who have sex with men in Canada and the United States in the early 1980s.
