GSK says swine flu vaccine is effective after one dose

GlaxoSmithKline's (GSK) first clinical trial of its swine flu adjuvanted vaccine has shown that after one dose it can provide a "strong immune response" that exceeds the immunogenicity criteria for a pandemic influenza vaccine.

The trial, which is taking place in Germany, involves 130 healthy volunteers aged 18 to 60 years old, will evaluate GSK's split-virus pandemic (H1N1) adjuvanted vaccine in comparison with an unadjuvanted test study formulation.

In the trial, the antigen content of the adjuvanted vaccine is 5.25μg and in the unadjuvanted vaccine it is 21μg. The antigen content of the adjuvanted vaccine is comparable to the expected final formulation of the adjuvanted vaccine of 3.75μg.

The results of the adjuvanted vaccine demonstrated that haemagglutination-inhibition titres exceeded the regulatory threshold, with a 1:40 seroconversion in more than 98% of subjects receiving the first dose. In the unadjuvanted group, 95% of the subjects reached the same threshold. These results were obtained three weeks after vaccination.

"This trial provides encouraging data on the potential use of a single dose of our pandemic vaccine," said Jean Stephenne, president of GlaxoSmithKline Biologicals.

GSK is conducting a further 15 studies in more than 9,000 subjects including healthy adults, the elderly and children (including infants) across Europe, Canada and the US. All data will be submitted to the regulators as soon as available and posted on GSK's Clinical Study Register.