June 19, 2007 A significant new flu vaccine with the potential to protect against all strains of influenza, including pandemic and annual, was unveiled yesterday. Previously undisclosed pre-clinical data showing how PepTcell’s FLU-v vaccine has such groundbreaking and lifesaving potential was presented at the 2007 Options for the Control of Influenza Conference, in Toronto, Canada. The results show that a vaccine targeted at parts of the virus which do not change from year-to-year, can be effective against lethal influenza strains.

The pre-clinical results, which will be published in the European Journal of Immunology, showed how mice vaccinated with PepTcell’s novel flu vaccine, FLU-v, had a significantly increased survival rate when challenged with a lethal dose of influenza virus, compared with those that received a control vaccine.

Dr Wilson Caparros-Wanderley, PepTcell’s Chief Scientific Officer said: “These are extremely encouraging results for PepTcell’s FLU-v vaccine. They show that a vaccine, targeted at parts of the virus which do not change from year-to-year, can be effective against lethal influenza strains.”

The data showed how PepTcell has used a novel proprietary prediction algorithm to locate conserved immunogenic regions in animal and human strains of flu virus. The analysis identified six highly conserved regions within several proteins that are capable of triggering an immune response.

These six regions were then chemically synthesised as small protein fragments called peptides. The resulting preparation, FLU-v, was used to immunise eight transgenic mice. At the same time a group of eight control mice were immunised with a set of non-related peptides.

Following immunisation with FLU-v the mice launched a specific T-cell immune response of the CD8+ subtype against the peptides. T-cells are part of the immune system, helping to fight off infection and disease by killing abnormal cells. The CD8+ T-cells isolated from the mice showed activity against human cells infected with three unrelated influenza strains in in vitro tests. This experiment confirmed that the peptide sequences in Flu-V are highly conserved across strains, and that these peptides are naturally presented on the surface of flu-infected cells, and therefore can be recognised by the immune system.

When the immunised mice were subsequently challenged with a lethal dose of influenza, the researchers found that fifty seven percent of the mice who had been immunised with the FLU-v vaccine survived, compared with none of the mice in the control group.

Greg Stoloff, Managing Director of PepTcell, commented: “These results suggest that PepTcell’s FLU-v vaccine could eliminate the need for annual flu vaccination as the immunity generated targets regions of the virus that remain constant. The results also suggest that FLU-v has the potential to provide effective protection against a pandemic flu strain by enabling stockpiling and the initiation of a worldwide vaccination program ahead of an outbreak.”

PepTcell is in the process of finalising all the manufacturing processes for its vaccines, and expects FLU-v to enter Phase I clinical trials during 2008.