Intranasal pandemic flu vaccine enters clinic

Avir Green Hills Biotechnology's intranasal vaccine deltaFLU for the treatment of pandemic influenza is commencing Phase I clinical trials.

deltaFLU's preclinical trials were regarded as a success by the company, which is now keen to push on with further testing to establish safety and efficacy in healthy volunteers.

By delivering the vaccine directly to the nasal passages, as opposed to the muscles, protection is stimulated at the site of virus entry.

Andrej Egorov, vice president for research at Avir, said: " We are very pleased about the success of our vaccine in the preclinical studies.

The data are superb and exceed our highest expectations ."

Avir believes that intranasal delivery via a spray device offers numerous advantages over traditional injections into the muscle.

The company claims it is an easier, painless route of administration, which offers " significantly higher efficacy rates ".

This is attributed to the fact that intranasal delivery stimulates vaccine production at the entry point for a virus.

In addition, as deltaFLU is a live attenuated vaccine the company believes it will induce longer lasting and more cross-protective immunity.

This refers to the vaccines ability to immunise a patient against a wide range of influenza virus variants.

It could also " provide protection against distantly related "drift variants" of pandemic influenza strains ".

Although deltaFLU apparently induces a stronger immune response the company also believes it is safer than other vaccines as its NS1 gene is deleted. Thomas Muster, CEO of Avir, said: " Our vaccine lacks the pathogenicity factor NS1.

Due to this deletion, the vaccine is likely to show a superior safety profile.

We are confident that the pandemic deltaFLU vaccine will be tolerated even at high doses ."

Studies into the H5N1 avian influenza virus have shown that changing an amino acid on the NS1 gene can greatly reduce its pathogenicity.

By creating a virus without NS1 the company believes that unexpected complications from the virus are unlikely, even in young children, the elderly and immunocompromised people.

Green Hills is manufacturing the vaccine using cell culture and believes that this, in conjunction with its knowledge of reverse genetics, enables it to generate a vaccine against any potential influenza virus in a short space of time.