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PowderMed's DNA-Based Flu Vaccine Shows Cross-Protective Immunity Against Genetically-Drifted Flu Strains, Offering Potential for Vaccine Effective Against Emerging Flu Variants

Posted on: Monday, 19 December 2005, 09:00 CST

Results of Phase 1 Clinical Trial Presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC)

Since the circulating influenza strains for any given season cannot be precisely predicted, an effective influenza vaccine should be able to generate protection for both the genetically identical (homologous) strain of flu as well as genetically-drifted (heterologous) strains. This is even more important in the case of vaccines developed against avian influenza (so called bird flu) where the human strain cannot be precisely predicted from the strains circulating in the bird population. For the first time in humans, DNA-based vaccines and immunotherapeutics company PowderMed has shown that its H3/Panama DNA-based influenza vaccine shows cross-protective immunity against both an homologous H3 flu strain as well as four drifted heterologous H3 strains. This suggests that the vaccine could be particularly useful in providing a means of vaccinating against emerging variants of annual influenza. Importantly, these results also provide evidence that PowderMed's vaccine approach may be particularly useful in addressing potential pandemics from avian influenza (bird flu).

Dr. John Beadle, PowderMed Chief Medical Officer, who presented the data at ICAAC, said, "Circulated influenza cannot be precisely predicted, the strains change every season. These results suggest that our vaccine could play a key role in future defense strategies against both annual flu and the pandemic threat. For bird flu, it is particularly important that vaccines are able to cover a range of drift variants since the virus is likely to change very rapidly early in the pandemic."

These positive results from a phase I clinical trial, were presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Washington, D.C. on December 17. Using Particle Mediated Epidermal Delivery (PMED(TM)), PowderMed's needle-free injection system, a DNA plasmid encoding the H3 haemagglutinin (HA) gene for Panama flu was administered to 36 healthy volunteers. The trial examined the safety, tolerability and dosing implications of the DNA vaccine at three doses (1, 2 and 4 micrograms) each given on a single occasion. The immune response was assessed according to the criteria laid down by the Committee for Proprietary Medical Products (CPMP) for the approval of annual flu vaccines in the European Union. The 2 and 4 microgram doses achieved the CPMP defined immune response at 56 days, with the maximum dose passing the criteria at 21 days. In addition, samples were further analysed to assess the affect of the vaccine on three genetically-drifted H3 stains of influenza. The PMED DNA vaccine was shown to have a favorable response to all the strains tested.

The current results suggest that the PMED DNA method will provide useful prophylactic vaccine defense against influenza and PowderMed will initiate phase II studies using both bird flu strains and annual flu strains in 2006. The Company is currently expanding its manufacturing capabilities in Europe in line with capacity requirements for production of its vaccines.

About PowderMed, Ltd

PowderMed is a private immunotherapeutic company based in Oxford, U.K. The Company is focused on the clinical development and manufacture of therapeutic and prophylactic DNA-based vaccines for viral diseases and cancer. The company has 4 clinical and 3 pre-clinical stage projects. The lead clinical program has shown positive Phase I results in the treatment and prevention of human influenza. This technology is uniquely and easily adaptable to treat avian flu and to address the pandemic threat. PowderMed also has a product for the treatment of genital herpes in Phase I trials, and two partnered Phase I programs in Cancer (Ludwig Institute) and HIV/AIDS (Glaxo SmithKline). PowderMed vaccines are delivered using PMED(TM) (Particle mediated epidermal delivery), a needle-free, virtually painless delivery system that requires minimal medical training, allows self-administration, and requires no refrigeration for stockpiling. Specifically, PowderMed's technology delivers DNA to the epidermal layer of the skin, where it is presented to the cells of the immune network, thereby creating immunity and thus facilitating both treatment and prevention of disease. For more information, please visit http://www.powdermed.com.

Source: Business Wire

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