Isconova AB, a leading international vaccine adjuvant company, has announced the first results from a successful phase I study using its proprietary vaccine adjuvant, Matrix M. This study forms part of the clinical proof of concept for Matrix M and its utility in improving the clinical efficacy of seasonal influenza vaccines in the elderly. Both the primary as well as secondary clinical endpoints were reached.

In this trial, a group of elderly subjects (aged 65-75) were administered either Vaxigrip (seasonal influenza split vaccine) adjuvanted with Matrix M or Vaxigrip alone. The adjuvanted vaccine was well tolerated with an excellent safety profile. An increased number of minor side-effects compared to the non-adjuvanted comparator vaccine were observed, however these were mild and transient. No severe side-effects were recorded.

Both the adjuvanted and non-adjuvanted vaccines fulfilled all three EMA serological assessment criteria for regulatory approval of seasonal influenza vaccines. Higher antibody responses were seen in the Matrix M adjuvanted group.

Interferon gamma producing CD4 cells were found at significantly higher levels in the Matrix M group on days 28 and 90 and were still elevated on day 150. These cells are considered to be an important marker of a potent immune response.

The study confirms the clinical superiority of the Matrix M adjuvanted vaccine, already demonstrated by the use of Matrix M in the previously conducted pandemic influenza vaccine study in man (PanFluVac), by Isconova’s partner J&J/Crucell, including the important increase in the cell mediated immune response.

Professor Ab Osterhaus, world leading influenza expert and chief scientific officer of ViroClinics Biosciences BV, Rotterdam, commented, “The adjuvant Matrix M performed remarkably well in this human trial. It stimulated both antibody and cellular responses with an excellent safety profile.”

Sven Andréasson, chief executive officer of Isconova AB, Uppsala, commented, “This is an important achievement for us and is further evidence that Isconova’s proprietary Matrix M platform has the potential to improve vaccines for humans in a growing market where there remain major unmet needs. The data are crucial for the proof of concept for our further commercialization of Matrix M.”

Vaxigrip (seasonal influenza split vaccine) adjuvanted with Matrix M was tested and compared with Vaxigrip alone in two groups (n= 44 per group) of elderly subjects, aged 65-75. The specific T-cell mediated response was significantly higher in the group receiving the Matrix M adjuvanted vaccine. This was measured with respect to the percentage of influenza virus reactive CD4+ cells producing: Interferon gamma at day 28 and 90 (P<0.05). Both the adjuvanted and non-adjuvanted vaccines induced high levels of antibodies and both groups conform to all three EMA serological assessment criteria for regulatory approval of seasonal influenza vaccines; The Hemagglutination Inhibition (HI) Seroconversion Rate; was higher against all three strains in the Matrix MTM adjuvanted vaccine. Even at day 150, seroconversion rates were 8% or higher among elderly receiving the Matrix M adjuvanted vaccine.

The Geometric Mean Titer (GMT) increase of HI; was higher for all three strains in the Matrix M adjuvanted vaccine at day 28 and 150. The Seroprotection Rate by HI; was equal or higher for all three strains in the Matrix M adjuvanted vaccine at day 28 and 150. The GMT increase of Virus Neutralization Antibodies (VNA) was significantly higher for the  homologous H1N1 strain in the Matrix M adjuvanted vaccine group at day 28 and 90. In addition, the GMT increase of VNA was higher for the homologous B strain in the Matrix M adjuvanted vaccine group at day 28 and 150.

The Matrix M adjuvanted vaccine was well tolerated. An expected increase of minor side-effects compared to the non-adjuvanted comparator vaccine was observed. The reactogenicity was mild and transient. No severe side effects were recorded. The results of this phase I study in elderly subjects demonstrate that Matrix M is well tolerated and significantly stimulates the T-cell response. Furthermore, the results indicate an increase of the serological response and duration.

The study forms a part of the clinical proof of concept for the further development of Matrix M adjuvanted seasonal influenza vaccines with the potential for an increased clinical efficacy in the elderly population.

Isconova AB has deep knowledge of vaccine systems, and the company develops vaccines together with partners in the human and veterinary markets.