Significant gains have been made in the last year and a half in the development of the first ever genetically modified, preventative “killed whole virus” HIV vaccine also known as SAV001. Dr. Chil-Yong Kang of Western University’s Schulich School of Medicine & Dentistry leads the team of researchers working on the vaccination. Sumagen Canada, a biotechnology company (specializing in HIV and AIDS research and development) is providing the financial support for this research and exclusively holds the patents and rights to the vaccine. As of when this article was written, this is the only vaccine in Canada currently in clinical trials and one of only a handful of vaccines being tested globally. Scientists have been endlessly challenged in developing an HIV vaccine given the virus’s complexity and rapid mutation.
Following the United States Food and Drug Administration’s (FDA)* approval in March 2012, Phase I of clinical testing began and finished in August 2013 reporting no major adverse effects on human volunteers. Phase I of the randomized (observer-blind) study involved 40 asympotomtic HIV-positive men and women between the ages of 18 and 50, half of whom are intramuscularly injected with the vaccine (containing dead virus, genetically modified to be non-pathogenic or unable to cause disease) while the other half receives a placebo . In addition to relatively few adverse side effects reported, it was found that some of the test subjects who were injected with SAV001 responded with increased antibodies, which is promising for potential success in Phase II of clinical testing Participants were intermittently monitored at weeks 4, 6, 12, 18, 26 and 52 post vaccine injection and were subjected to a battery of tests to determine any negative side effects they may be experiencing.
While the “killed whole virus” approach is relatively new to HIV vaccine development, historically, it has been used quite successfully with the likes of polio, influenza, rabies, and hepatitis A vaccines. Soon after the discovery in 1983/84 that HIV was the cause of AIDS did talk of vaccine development begin though it was not until 1986 that the first HIV vaccine trial began in Zaire (now the Democratic Republic of Congo)**. Though the first trial did not amount to much, it was the catalyst for subsequent trials. Over the last three decades, several different approaches have been taken to the development of an HIV vaccine, many of which have failed (Merck’s infamous vaccine tested in the STEP trial which enrolled 3,000 participants globally and was abruptly halted when it was discovered that more participants receiving the vaccine seroconverted than those receiving the placebo) with only a handful of moderate successes, including the most recent gains of SAV001.
Phase II of the trial will be testing globally the immune responses of 600 HIV-negative (though deemed “high-risk” participants whose “lifestyles” increase their chances for seroconversion) human participants to see whether the vaccine produces HIV antibodies. Phase III is expected to test the vaccine’s efficacy amongst a sample of approximately 6,000 “similarly at-risk” participants with the intention of monitoring these participants over the course of three years to track how many participants seroconvert. It’s unclear exactly when Phase II of the trial will commence; given the expansion in participant numbers and that the trial aims to test globally, recruitment may be time consuming.
The tremendous potential of SAV001 is mind-boggling. While I try to remain cautiously and realistically optimistic (read: the likelihood of this vaccine succeeding is nil), I cannot help but wonder what our world would look like if HIV did not live in it. Perhaps another virus fuelled by social inequalities, poverty, stigma, homophobia, racism, neo-colonialism, etc. etc. etc. would exist, easily taking HIV’s place and wreaking havoc wherever it went. Or maybe the world would be even more over-populated than it already is and we would be facing a whole slew of other issues. Maybe we will never know. Or maybe, just maybe, instead of writing on the many horrors of HIV, I will one day be writing on the history of the end of HIV and AIDS.
* Testing is being conducted in the United States of America
** For a thorough overview of the global history of HIV vaccines, please see this article.