GAITHERSBURG, Md., March 20 Iomai Corporation(Nasdaq: IOMI) today announced positive interim results from the 500-subjectPhase 1/2 trial of its immunostimulant adjuvant patch used with an injectedvaccine for H5N1 influenza. The trial met a key endpoint, demonstrating aclinically relevant adjuvant effect when the Iomai patch was used with asingle dose of the 45-microgram H5N1 vaccine. The trial found that a single45-microgram dose of an H5N1 influenza vaccine, coupled with a single50-microgram Iomai patch, was sufficient to provide an immune responseconsidered protective in 73 percent of those tested, a statisticallysignificant improvement over those who received the H5N1 influenza vaccinealone.
This is one of the first trials to demonstrate that a single dose ofpandemic influenza vaccine may meet the level of protection suggested in U.S.Food and Drug Administration guidance, which recommends that a pandemicvaccine achieve immune response levels considered protective in 70 percent ormore of vaccine recipients. The trial was conducted under a $14.5 millioncontract with the U.S. Department of Health and Human Services (HHS) with thepotential for an additional $114 million in follow-on funding. Iomai hasshared the data with HHS and is now working with them to determine the nextsteps.
The only FDA-approved vaccine in the United States for the avian influenzaH5N1 virus requires two 90-microgram doses, administered 28 days apart, toachieve hemagglutinin inhibition (HI) titers equal to or greater than 40 in44 percent of vaccinated individuals.
"During an influenza pandemic, public health officials will face two largehurdles. The first is the possibility of limited vaccine stocks. The second isthe logistic difficulty of administering two vaccinations over a period ofseveral weeks to all individuals in the face of a pandemic. This new researchclearly indicates that a single dose of vaccine in combination with an Iomaipatch could provide a significant level of protection, achieve protectivelevels more rapidly, and increase compliance," said Stanley C. Erck, Presidentand Chief Executive Officer of Iomai. "This is a major breakthrough and couldprovide public health officials with an important solution for this loomingproblem."
The trial tested three different dose levels of Solvay Biologicals, B.V.(Netherlands) egg-derived H5N1 influenza vaccine, the adjuvant patch andplacebo to determine which combinations would be most effective in atwo-immunization regimen, administered 21 days apart. Data showed that92 percent of the 50 subjects vaccinated a single time with the 45-microgramdose in combination with the Iomai patch had an immune response. Seventy-threepercent of those subjects achieved an HI titer of greater than 40, which isconsidered protective, offering the potential to eliminate the need for asecond vaccination. About 49 percent of those who received the vaccine alone,without a patch, had an immune response considered protective after the firstdose, and the 24 percentage point difference between the patch and no-patchgroups was statistically significant (p<0.0001). A second dose of both vaccineand patch further enhanced immunogenicity; 100 percent of subjects whoreceived two 45-microgram doses of vaccine and two Iomai patches had ameasurable immune response, and 94 percent of subjects had immune responsesconsidered protective.
No treatment-related serious adverse events were reported.
With further testing, the patch has the potential to be used inconjunction with other injected pandemic influenza vaccines. It has been shownto be suitable for ambient temperature shipping and handling, and has at leasta 2-year storage shelf life, making the product ideal for stockpiling andrapid distribution. The patch is easily applied and acts like an adhesivebandage placed at the site of the injection.
"This data also confirms ou