Iomai Study Shows Self-Applied Travelers' Diarrhea Vaccine Patch Comparable to Clinician-Applied Vaccine Patch

Iomai Study Shows Self-Applied Travelers' Diarrhea Vaccine Patch Comparable to Clinician-Applied Vaccine Patch

GAITHERSBURG, Md., Feb 12, 2008 -- Iomai Corporation today announced the interim results of a study that showed that the second dose of the two-dose regimen for its novel, patch-based travelers' diarrhea vaccine yields a robust immune response when self-applied by subjects outside of a clinical setting.

The 160-subject study, part of an extensive Phase 2 program for the vaccine, measured the immune response to the vaccine patch, which is approximately the size and shape of an adhesive bandage. Four groups were evaluated: two groups received both doses of the vaccine from a medical professional and two other groups of volunteers administered the second vaccine patch themselves. All groups had robust responses to the vaccine, and a statistical analysis of immune parameters following vaccination showed no significant differences between treatment groups at any time point.

"These results confirm our belief that the Iomai patch can be effectively used by patients without a health care provider present, removing the need for a second trip to a travel clinic," said Stanley C. Erck, Iomai's president and chief executive officer. "Our research has shown that self-application of the second dose further enhances the market potential of this product."

As with past studies of the vaccine, no serious vaccine-related adverse events were reported.

Iomai is completing its Phase 2 program and plans to conduct a Phase 3 efficacy study during summer of 2009, when the travelers' diarrhea season in Latin America is at its peak. Based on the results of the self-application study, Iomai is evaluating the feasibility of including self-administration of the second vaccine dose in that Phase 3 study. The data also suggests the possibility of self-administration of other Iomai vaccines, such as the needle-free influenza vaccine, which remains a priority for the company.

Last year, the company presented data from a Phase 2 field trial of the travelers' vaccine at the Interscience Conference on Antimicrobial Agents and Chemotherapy that demonstrated people who received the vaccine before traveling to Mexico or Guatemala were significantly less likely to report clinically significant diarrhea. Of the 59 individuals who received the vaccine, only three suffered moderate or severe diarrhea, while 23 of the 111 who received a placebo suffered moderate or severe diarrhea, a 75 percent reduction (p=0.007). One of the 59 volunteers in the vaccine group reported severe diarrhea, compared with 12 of the 111 in the placebo group, an 84 percent reduction (p=0.033).

About Travelers' Diarrhea

This year, approximately 55 million international travelers will visit countries where bacteria that cause travelers' diarrhea are endemic, particularly Africa, Asia and Latin America, and about 20 million of those travelers will develop travelers' diarrhea.

A recently completed market study suggested that there is a large market for an effective travelers' diarrhea vaccine, potentially exceeding $750 million annually. If approved, the Iomai vaccine would be the first vaccine for travelers' diarrhea available in the United States.

ABOUT IOMAI CORPORATION

Iomai Corporation discovers and develops vaccines and immune system stimulants, delivered via a novel, needle-free technology called transcutaneous immunization (TCI: 15.23, -0.15, -0.97%). TCI, discovered by researchers at the Walter Reed Army Institute of Research, taps into the unique benefits of a major group of antigen-presenting cells found in the outer layers of the skin (Langerhans cells) to generate an enhanced immune response. Iomai is leveraging TCI to enhance the efficacy of existing vaccines, develop new vaccines that are viable only through transcutaneous administration and expand the global vaccine market. Iomai currently has four product candidates in development: three targeting influenza and pandemic flu and one to prevent travelers' diarrhea. For more information on Iomai, please visit http://www.iomai.com.

Some matters discussed in this press release constitute "forward-looking statements" that involve known and unknown risks and uncertainties that could cause actual results to differ materially from those expressed or implied by the forward-looking statements. Such forward-looking statements include statements that Iomai will successfully commercialize its travelers' diarrhea vaccine patch; that such vaccine would be approved with self-application of any dose; statements about Iomai's plans to initiate a Phase 3 study in the summer of 2009 and the potential size of the market for a travelers' diarrhea vaccine; and that, if approved, Iomai's vaccine would be the first available in the U.S. Applicable risks and uncertainties include, among others, that Iomai may not be able to enroll sufficient numbers of patients in future clinical trials; that future clinical trials may not replicate results seen in the trial described in this press release; that Iomai may be unable to obtain the regulatory approvals or financing necessary to conduct additional clinical trials, to conduct those trials in the indicated timeframes or to market any product for travelers' diarrhea; that the FDA or other regulatory authorities may not concur with Iomai's analysis of the trial results described in this press release; that estimates of market size overstate the number of travelers who would use such a product, if it were approved; that competitors may develop products that are safer, more effective, or more convenient to use; and the risks identified under the heading "Factors That May Impact Future Results" in Management's Discussion and Analysis of Financial Condition and Results of Operations in Iomai's Quarterly Report on Form 10-Q for the three months ended September 30, 2007, and filed with the Securities and Exchange Commission. Whether any approved product would be self-administered would depend on many factors, including the outcome of any additional studies the Company conducts evaluating self-administration and the views of regulatory agencies. Iomai cautions investors and others not to place undue reliance on the forward- looking statements contained in this press release. Iomai's business is subject to many risks. For a discussion of such risks, you are encouraged to read the documents the Company files with the U.S. Securities and Exchange Commission, available at http://www.sec.gov. The statements in this press release speak only as of the date of this document, and Iomai undertakes no obligation to update or revise the statements.