A candidate Ebola vaccine that uses Immunovaccine's formulation technology has stopped cynomolgus monkeys from catching the disease in a preclinical study.
The Canada-based firm announced the preclinical results this week, explaining that four monkeys given two doses of vaccine survived exposure to a lethal dose of the Zaire strain of the Ebola virus. Two unvaccinated control animals succumbed to the disease and died within seven days.
The study, which was carried out under a US NIAID contract , examined a vaccine made using Immunovaccine’s DepoVax tech, in which virus antigen and an adjuvant are encapsulated and suspended in oil in order to increase exposure time and immune response.
CEO Marc Mansour said: “These preliminary results are encouraging and support the continued evaluation of an Ebola vaccine in DepoVax, potentially leading to a clinical study."
Immunovaccine did not say when any clinical study of the DepoVax-Ebola vaccine would begin.
The DepoVax delivery technology is also being applied to vaccines for a range of other infectious disease including respiratory syncytial virus (RSV), which is due to enter trials this year, and HIV in collaboration with FIT Biotech .
GSK vaccine trials
The announcement comes just days after UK drugmaker GSK announced it had been given the green light to begin Phase I clinical trials of its Ebola vaccine.
The vaccine – which also protects against the Zaire strain of the Ebola virus – was developed by recent GSK acquisition Okairos and is based on its advenovirus vector delivery technology.
The Okairos approach is to use adenoviruses produced in the Procell92 cell line to deliver genes that encode Ebola virus proteins. These proteins – when expressed by infected cells – induce CD8 T cell responses that confer immunity to infection.
Using adenovirus vectors in this way is not a new idea , however, Okairos’ claim that its viruses avoid the neutralising antibodies that have hampered the development of other vaccines is what marks the technology out.
“Our scientists have met the challenge of high seroprevalence, associated with existing adenovirus vectors, by isolating and extensively characterising a large number of adenovirus strains from non-human primates. New, highly potent adenovirus vectors, not neutralised by antibodies present in humans, have been developed.”
The GSK study is expected to begin at a research centre in Oxford, UK next week .