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VANCOUVER -- ID Biomedical reported today that it has data demonstrating protection against variant strains of influenza.
Results from pre-clinical experiments performed by ID Biomedical scientists and recently published in the September 2003 issue of the peer reviewed journal, Vaccine, provides evidence that nasal Proteosome -- influenza subunit vaccines can protect against infection by variant strains of influenza virus that have 'drifted' from the strain present in the vaccine. In the study reported by Jones et al. in Vaccine vol. 21 pp. 3706-3712, mice were given a nasal Proteosome-influenza vaccine containing a recombinant influenza hemagglutinin (HA) from the A/Texas H1 subtype of influenza. Mice were then exposed to a lethal dose of a mouse-adapted A/Taiwan H1 strain of influenza virus which was not present in the trivalent composition of the vaccine. The A/Taiwan and A/Texas strains represent drift variants within the H1 subtype.
Nasal immunization with the subunit Proteosome-A/Texas vaccine protected 100 percent of the mice against mortality and weight loss (a sign of clinical illness) following exposure to the live A/Taiwan drift variant virus. The same challenge dose of live A/Taiwan virus caused 100 percent mortality in non-vaccinated control animals. Mice that received an intramuscular vaccination with the same dose of A/Texas HA (not formulated as a Proteosome-HA vaccine) were also protected against death following exposure to the live drift variant virus but experienced significant illness as demonstrated by a 13 percent loss in weight. Only the nasal Proteosome-HA subunit vaccine induced detectable mucosal IgA in the respiratory tract which may explain the enhanced cross-protection shown by the mucosally-delivered Proteosome-subunit influenza vaccine.
"This flu season we have a similar situation. Flu vaccines including FluINsure have been designed to protect against the A/Panama strain of influenza but the predominant strain causing influenza appears to be A/Fujian, a variant of the A/Panama strain." David Burt ID Biomedical's vice president of research stated. "These pre-clinical findings suggest that FluINsure may also protect humans against drift variant strains of influenza which are in circulation and which are not identical but are closely related to the strain present in the vaccine."
FluINsure, ID Biomedical's nasal Proteosome-influenza subunit vaccine is currently being tested in a 1,345 subject field efficacy study. In phase II clinical trials, FluINsure protected human volunteers against laboratory confirmed influenza following experimental challenge with a strain of live influenza virus which was identical to one of the three strains represented in the vaccine.
ID Biomedical is a biotechnology company focused on the development of proprietary subunit vaccine products, including those based on its Proteosome platform intranasal adjuvant/delivery technology.
Source: ID Biomedical Corporation