UNIQUE FLU VACCINE TRIAL T0 START IN LONDON - Opportunity to Trial New Vaccine That Could Help In the Fight Against Annual and Pandemic Flu

Oxford, U.K. – 21 September 2006 … With winter on its way and the flu season about to begin Londoners are being offered the opportunity to sign up for a unique clinical trial to test a new DNA Vaccine. The trial, which has received approval from the UK Medicines and Healthcare Products Regulatory Agency (MHRA), will test for the first time whether a DNA vaccine can protect people from infection with influenza.

If successful, this challenge study could pave the way for DNA vaccines such as this H3 vaccine for annual flu and PowderMed’s H5N1 pandemic vaccine, to reach market approval. PowderMed also started a trial on the H5N1 DNA vaccine last month.

PowderMed’s Chief Medical Officer, Dr John Beadle said “This particular trial is unique because it will be the first to assess the ability of our DNA vaccine to protect human volunteers against flu. What we are looking for are people willing to be vaccinated and then later challenged with an annual flu virus. Some of them may get a mild form of influenza like illness, but our previous data suggests that those who are vaccinated may be protected. All volunteers will receive, at the end of the study, treatment with Tamiflu a licensed antiviral drug”.

This trial is one of three being conducted this year by UK company PowderMed to assess the ability of DNA vaccines to protect against annual and pandemic influenza. PowderMed’s DNA vaccines use a proprietary needle-free system to deliver microscopic gold particles coated with DNA at supersonic speed into the immune cells of the skin. Previous studies have shown that these vaccines can protect animals from challenges with either annual or bird flu viruses and produce a protective level of immune response in humans.

The first phase of the trial is being conducted at Guys Drug Research Unit (GDRU), Quintiles UK Ltd in London. Dr Tim Mant, Senior Medical Advisor, GDRU said that “Annual flu is debilitating for many and life threatening for some; flu is a major public health issue and we feel it is important to contribute to knowledge about potential new vaccines. We are currently screening volunteers to determine whether they may be eligible to enroll in this influenza vaccine study.”

Later in the trial the volunteers will be accommodated for ten days in a residential facility, where they will be challenged with an enfeebled version of the H3N2 strain of influenza virus which is known to cause annual influenza in non-immunised people. At the end of this period the volunteers will all be given Tamiflu, an antiviral drug, already approved for use in the UK to reduce the duration of any potential influenza symptoms.

Full details of this clinical study and directions for potential volunteers can be found at www.clinicaltrials.gov. Anyone interested, who is otherwise healthy and aged between 18 and 50, should contact Quintiles at Guys Drugs Research Unit on 0800 634 1130.

-ENDS-

Notes to editors

About PowderMed - www.powdermed.com

PowderMed is a private immunotherapeutic company based in Oxford, UK. 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 programme 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 programmes in Cancer (Ludwig Institute) and HIV/AIDS (Glaxo SmithKline). PowderMed vaccines are delivered using PMEDTM (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.

PowderMed’s influenza vaccines

PowderMed’s DNA vaccines are made up of two components – the vaccine-specific DNA and the delivery device. This approach provides a rapid route to vaccine development that can be applied to existing and emerging flu strains including, for example, the threat of the emergence of a pandemic flu strain.

PowderMed has two flu vaccines in development for annual and avian flu (H3 and H5 strains). Results of previous preclinical and clinical testing of PowderMed’s DNA-based influenza vaccines, including H3 and pandemic H5 strains utilising PMED, show consistent and robust immune responses in animals and humans at micro-gram doses.

The DNA vaccine consists of the standard DNA backbone with an immunologically active gene specific to each viral strain – the gene cassette.

The delivery device is a fully developed and patented system, called Particle Mediated Epidermal Delivery (PMED™), whereby gold particles coated in the vaccine DNA are propelled into the skin using high-pressure helium (see below). In this way, vaccine DNA is delivered directly to cells of the immune network in the skin, thereby stimulating immunity.
PowderMed’s annual flu vaccine uses the gene encoding for the protein of the H3/Panama strain. In the case of the Avian flu vaccine, the H5 Vietnam gene cassette is used. This gene is specific to current Avian flu and encodes part of the flu virus’ protein shell. When the vaccine is administered, into the surface of the skin, the H5 gene is expressed to produce the virus protein. This harnesses the individual’s immune system to mount an immune response against the protein, such that, in the event of later exposure to actual Avian flu virus, the immune system will be able to destroy the flu virus and thus provide protection.
Using PowderMed’s technology, vaccination is needle free, virtually painless, can be easily administered without the need for trained medical personnel and it can be stored at room temperature making it ideal for large volume stockpiling and distribution.

The Company has developed a full clinical trial and manufacturing strategy that anticipates the demands that Governments may have for both annual influenza vaccine and a pandemic flu vaccine.

Background to Influenza

Flu is an acute viral infection of the respiratory tract caused by the Influenza virus. There are many different subtypes or strains of Influenza viruses, differentiated by proteins on the surface of the virus: the hemagglutinin or “HA” protein and the neuraminidase or “NA” protein. So far, 15 H and 9 N subtypes have been identified.

These viruses continually change over time and every year small modifications (“antigenic drifts”) are responsible for seasonal outbreaks or “epidemics” of Influenza. Worldwide, an estimated 100,000 hospitalisations and about 20,000 deaths occur each year from the flu or its complications (source: The National Institute of Allergy and Infectious Diseases).

Abrupt genetic recombinations of HA and/or NA proteins on the surface of the virus (“antigenic shifts”) result in the emergence of a new virus, which is a key step towards a pandemic strain. To date, there is little evidence that the H5N1 virus (associated with Avian flu) is capable of spreading from human to human, a pre-requisite for a pandemic strain, but should recombination (antigenic shift) of H5N1 occur, this strain could become responsible for a global outbreak of the disease or pandemic, with high levels of illness and death. The WHO (World Health Organization) has reported 97 human cases of avian flu since 26 December 2003. Since that date 53 deaths have been reported.

Previous Influenza pandemics:

1918-1919 “Spanish flu” (H1N1) with up to 50 millions deaths worldwide.
1957-1958 “Asian flu” (H2N2) caused about 70,000 deaths in the US
1968-1969 “Hong Kong flu” (H3N2) caused about 34,000 deaths in the US
Both the 1957-1958 and the 1968-1969 pandemics were caused by viruses containing combinations of human and avian Influenza viruses.

Particle Mediated Epidermal Delivery (PMED™) technology

Using the PMED™ device, DNA precipitated onto microscopic gold particles is propelled by pressurised helium gas at near supersonic speeds into the epidermis. The microscopic gold particles (mean particle diameter 1 - 3 microns) are used as the carrier because they have the appropriate size and density needed to deliver the DNA directly into the immunologically active antigen presenting cells (APCs) of the epidermis. These cells have a mean diameter of 20 microns and thus the microscopic gold can easily enter the cell. Studies have shown that once inside the nuclei of APCs, the DNA elutes off the gold and becomes transcriptionally active, producing the encoded protein that, when presented by the APCs to lymphocytes, triggers strong T-cell mediated immune responses. It is this ability of PMED to produce a robust and reproducible T-cell mediated immune response to a broad range of viral and cancer antigens, that provides PowderMed with its unique competitive advantage in the field of DNA-based vaccines.

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Dr John Beadle
Chief Medical Officer
Tel: +44 (0)1865 501 532
john.beadle@powdermed.com

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