Sanofi pasteur, the vaccines business of the sanofi-aventis Group’s preliminary results of clinical trials fielded in France of an adjuvanted candidate H5N1 pre-pandemic influenza vaccine demonstrated a good immune response in a significant number of volunteers. This is the first trial of an H5N1 pre-pandemic influenza vaccine candidate that compared vaccines with and without adjuvants.

Preliminary results showed that the vaccine is safe and well-tolerated in 300 healthy volunteers. A 30 microgram-dose with an adjuvant in a two-dose regimen demonstrated an immune response at levels consistent with requirements of regulatory agencies for licensure of seasonal influenza vaccine, states a company release.

Sanofi pasteur characterised the preliminary results as a sign of progress and providing direction for further development of a pandemic influenza vaccine. The company also noted that immune responses were detected in a number of volunteers receiving lower doses. Subsequent trials will explore different dosages, which may be helpful in answering questions about dose-sparing strategies and which are being widely discussed among the public health community.

The trial was sponsored by sanofi pasteur and fielded in three sites in France: Necker and Cochin Hospitals in Paris, and Garches Hospital, with Professor Jean-Louis Bresson as the principal investigator.

The vaccine used the reference strain provided by the UK’s National Institute for Biological Standards and Control (NIBSC). Assays were performed at NIBSC and the UK Health Protection Agency.

As definitive results become available, they will be presented to the European Agency for the Evaluation of Medicinal Products (EMEA).

Influenza is a highly contagious virus that is spread easily from person to person, primarily when an infected individual coughs or sneezes.

Sanofi-aventis is the world’s third-largest pharmaceutical company, ranking number one in Europe.