4th September 2013

Phase I clinical trials of AIDS vaccine successful

Phase I clinical trials of the first and only preventative HIV vaccine have been successfully completed with no adverse effects in all patients. Antibody production was greatly boosted after vaccination.

Developed by Dr. Chil-Yong Kang and his team at Western's Schulich School of Medicine & Dentistry, with the support of Sumagen Canada, this vaccine (SAV001-H) holds tremendous promise for success in the final phases of clinical testing, now that the first hurdle has been accomplished. It is the only HIV vaccine developed in Canada currently in clinical trial, and one of only a few in the world.

This vaccine is the first genetically modified, killed whole virus vaccine in human clinical trial to evaluate its safety, tolerability and immune responses. Following earlier success in animal subjects, the human clinical trial was initiated in March 2012 and completed in August 2013. This trial was a randomised, observer-blinded, placebo-controlled study of killed whole HIV-1 vaccine, following intramuscular administration. HIV-infected, asymptomatic men and women, aged from 18 to 50, were randomised into two treatment groups to administer either SAV001-H or a placebo.

Adverse effects after vaccination were recorded on a diary card by each of the volunteers, seven days after vaccination. Thereafter, the volunteers visited the test sites on weeks 4, 6, 12, 18, 26 and 52 after vaccination and were analysed for haematology, clinical chemistry, urinalysis and physical examination. No serious adverse effects were observed in any volunteers throughout the observation periods.

In addition to safety evaluation, HIV-1 specific antibody detections were performed in the follow up period. The antibody against p24 capsid antigen (which makes up most of the HIV viral core) was boosted as much as 64-fold in some people, while the antibody against gp120 surface antigen increased up to eight-fold. These antibody concentrations were maintained throughout the 52 week study period – a highly encouraging result, since these broadly neutralising antibodies are the most important parameter of an effective HIV vaccine.

HIV/AIDS has killed 35 million people worldwide, and more than 34 million currently live with the infection. Since the virus was characterised in 1983, there have been numerous trials through pharmaceutical companies and academic institutions around the world to develop vaccines; however, none have been successful to date. Other HIV vaccines evaluated through human clinical trials have focused on either one specific component of HIV as an antigen, a genetic vaccine using recombinant DNA, or recombinant viruses carrying the HIV genes.

SAV001-H is unique and different from other vaccine candidates. It uses a genetically re-engineered whole virus genome which therefore eliminates its pathogenicity, with its virulence inactivated through chemical treatment and irradiation, finally arriving as the first "whole killed virus"-based HIV vaccine. This is much like the killed whole virus vaccines for polio, influenza, rabies and hepatitis A. The HIV-1 is genetically engineered to be safer and reproducible in large quantities.

Proving its safety was the greatest concern for this stage. With these encouraging results from the Phase I clinical trial, the researchers are now confident in developing SAV001-H as the first preventative HIV vaccine, which could arrive as early as 2017. They are now preparing for the next phases of trials to show its efficacy and immunogenicity.

"Even though Sumagen has struggled and spent a much longer time to overcome manufacturing difficulties and to meet the U.S. FDA's requirements, we have accomplished successfully Phase I Clinical Trial of SA001-H and proven that there is no safety concern in human administration," said Jung-Gee Cho, the CEO of Sumagen. "We are now prepared to take the next steps towards Phase II and Phase III clinical trials. We are opening the gate to pharmaceutical companies, government, and charity organisations for collaboration to be one step closer to the first commercialised HIV vaccine."

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