Intercell's Vaccine Enhancement Patch for Pandemic Flu Fails Phase 2 Trials

Intercell AG's (Vienna, Austria) investigational vaccine enhancement patch (VEP) system for avian H5N1 influenza has failed its Phase 2 clinical trial. Intercell is working under a contract with the US Department of Health and Human Services (HHS) to develop a dose-sparing approach with potential for a single dose immunization against pandemic influenza that combines an H5N1 vaccine with Intercell's adjuvant patch.

Following encouraging preclinical and clinical Phase 1 proof-of-concept trials conducted under the HHS contract, the clinical Phase 2 study was designed to determine the safety and the optimal combination/dose of an injectable H5N1 influenza vaccine (30 and 45 μg antigen) and Intrcell's VEP (50 and 100 μg LT adjuvant) applied at the injection site. A total of 500 healthy adults were recruited in 6 study groups.

The study was not able to identify the optimal combination of antigen and adjuvant because no statistically significant difference in seroprotection rates as measured by hemagglutinin inhibition (HI) assay was observed when comparing groups with and without VEP.

However, the study results demonstrated a good safety profile for all doses of injectable vaccine and adjuvant patches studied. Furthermore, 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.

Intercell intends to conduct further clinical evaluation using its VEP in combination with an injectable H5N1 vaccine to be supplied by GlaxoSmithKline as part of a collaborative agreement signed in December 2009. HHS and Intercell currently are considering the next steps for this development program.