Iomai Patch-Based Vaccine Cut Rate of Travelers' Diarrhea by 75 Percent in Phase 2 Field Study

CHICAGO and GAITHERSBURG, Md. -- Iomai Corporation announces that travelers who received the company's patch-based travelers' diarrhea vaccine were significantly less likely to be sickened as compared with travelers who receive a placebo, according to research presented today by chief scientific officer Gregory Glenn, MD, at a late-breaker presentation during the "Vaccines and Pediatric Infections" session of the 47^th annual meeting of the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) being held in Chicago.

"We have demonstrated that vaccinated travelers can dramatically cut their risk of diarrhea by using our needle-free patch," said Glenn, Iomai's founder. "Those who received the Iomai vaccination were much less likely to get sick, and those who were sickened had far milder illness than those who received a placebo. These are clinically significant results that suggest that the patch vaccine will address the most significant unmet need for travel medicine: prophylaxis for travelers' diarrhea."

The study found that of the 59 individuals who received the novel, patch-based 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).

"The results presented at ICAAC are the most robust ever shown in the prevention of travelers' diarrhea, and they suggest we may be near a turning point in the prevention of this common, often-serious disease," said Herbert L. DuPont, MD, professor and director of the Center for Infectious Diseases at the University of Texas School of Public Health and the principal investigator on the trial. "If Phase 3 trials for the vaccine validate these results, those of us in travel medicine will have an excellent new weapon in our arsenal."

The research was conducted in collaboration with researchers from the Johns Hopkins Bloomberg School of Public Health and the University of Texas School of Public Health.

Iomai plans to begin a Phase 3 program for the needle-free vaccine patch vaccine in 2008.

"We are moving this product ahead as quickly as possible," said CEO Stanley C. Erck. "This is a pressing, unmet medical need. Travelers' diarrhea is the most common travel ailment in the world, yet there are no effective vaccines available for the condition. A recently completed market study suggests that there is a $750 million market for effective protection against travelers' diarrhea, an opportunity that we are well-positioned to target."

The Trek Study followed 170 travelers to Mexico and Guatemala. Each volunteer received either two doses of the Iomai vaccine patch or a placebo, two to three weeks apart, with the last dose administered a week before travel. Travelers kept detailed diaries and received in-country checkups. The study met its primary endpoints, which were designed to evaluate the safety of the vaccine and the incidence of enterotoxigenic E. coli (ETEC) bacteria -- the most common cause of travelers' diarrhea. No vaccine-related serious adverse events were reported.

Of the few vaccinated patients who were sickened, the diarrhea lasted only half a day on average, while those in the placebo group endured two days of illness and more than twice as many loose stools. Although not statistically significant, the frequency of new-onset irritable bowel syndrome, a long-term consequence of travelers' diarrhea, was three times greater in placebo than vaccine recipients.

Iomai's vaccine uses an ETEC toxin delivered via a skin patch using the company's novel transcutaneous immunization (TCI) technology. ETEC causes illness through the toxins it produces, including one known as heat-labile toxin or LT. Iomai's unique patch-based vaccine enables the safe administration of this potent immunogen into the skin to stimulate the immune response.

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.

ETEC's impact goes beyond travelers. The World Health Organization estimates that children in the developing world suffer 210 million episodes of diarrhea caused by ETEC annually, causing 380,000 deaths each year.

Source: Iomai Corporation