Iomai has begun clinical trials for its immunostimulant (IS) patch to be used in conjunction with vaccines for pandemic influenza. Such a patch, which uses an adjuvant designed to boost immune responses, may have the effect of expanding limited vaccine supplies by allowing public health officials to use fewer or lower doses of vaccine.

The initial Phase 1/2 clinical trial of the patch found that a single 45-microgram dose of an H5N1 influenza vaccine, coupled with a single 50-microgram Iomai patch, was sufficient to provide an immune response considered protective in 73 percent of those tested, a statistically significant improvement over those who received the H5N1 influenza vaccine alone. The trial is one of the first to demonstrate that a single dose of pandemic influenza vaccine may meet the level of protection suggested in U.S. Food and Drug Administration guidance.

Iomai is developing the pandemic influenza patch technology with a $128 million grant from the National Institutes of Health.

The possibility of a global outbreak of a virulent influenza strain, such as the avian H5N1 strain, has spurred an international effort to examine ways to expand limited vaccine stocks. The concern is especially acute given recent studies suggesting that high doses of experimental vaccines are needed to induce immunity.

Our IS patch is designed to be used in conjunction with any manufactured influenza vaccine. After a dose of injected vaccine is given, the Iomai patch, similar in appearance to a small adhesive bandage, is placed over the vaccination site. Then the active component of the patch (the adjuvant) is carried by immune cells in the skin to the lymph nodes, which augments the immune response to the injected vaccine. 

Preclinical studies indicate that the IS patch can enhance the immune response to a wide variety of antigens. Previous clinical work showed that the adjuvant patch could enhance the immune response to injected seasonal flu in the elderly. This data and the recent results using the IS patch with H5N1 suggest that this strategy may be used for other applications where improved immunogenicity, decreased antigen doses or fewer immunization visits are desired. Recently, Iomai entered into an agreement with Merck to explore new applications for the IS patch.