Under a contract with US Department of Health and Human Services (HHS) Intercell has been working to develop a dose-sparing approach with potential for a single dose immunisation against pandemic influenza that combines a H5N1 vaccine with Intercell’s LT adjuvant patch.

The Phase II clinical study was designed to determine the safety and the optimal combination/dose of an injectable H5N1 influenza vaccine (30 and 45µg antigen) and Intercell’s VEP (50 and 100µg LT adjuvant) applied at the injection site. A total of 500 healthy adults were recruited in 6 study groups.

The study results showed a good safety profile for all doses of injectable vaccine and adjuvant patches studied. A dose-dependent response to the H5N1 antigen was observed. Anti-LT IgG titers in study subjects receiving the patch confirmed that Intercell’s VEP could consistently deliver the vaccine adjuvant.

However, the study did not identify the optimal combination of antigen and adjuvant because no significant difference in seroprotection rates as measured by Haemagglutinin Inhibition (HI) assay was observed when comparing groups with and without VEP.

Furthermore, Intercell plans to conduct further clinical evaluation using its VEP in combination with an injectable H5N1 vaccine to be supplied by GlaxoSmithKline (GSK) as part of a collaborative agreement signed in December 2009.

Thomas Lingelbach, chief operating officer of Intercell and CEO and president Intercell USA, said: “Single-dose protection against highly pathogenic pandemic influenza strains such as H5N1 is an important goal for pandemic protection, but one which has been shown to be challenging.

“We think that despite the inconclusive results, our Vaccine Enhancement Patch is uniquely positioned to have the potential to achieve single-dose protection and hence Intercell using its partner GSK’s vaccine intend to proceed with further clinical evaluation.”