Wednesday May 30, 2012 0 commentsMore than 2 million children may be spared disease annually
By Betsy Lynch
FORT COLLINS -- Hand, foot and mouth disease (HFMD) doesn't get much press in Colorado. Yet more than 2 million people suffer from its effects each year, primarily children.
The vast majority of cases are seen in Southeast Asia, but nowhere are people immune. And world-wide, HFMD is on the rise. Inviragen, a Fort Collins-based biotech company with international reach, is on the cusp of changing that. Inviragen has developed a highly purified, virus particle vaccine (INV21) against HFMD infections caused by enterovirus 71.
In a recent trial completed in Singapore, 100 percent of vaccine recipients demonstrated significantly increased EV71 immune responses after immunization, which may signify protection against the disease, according to Dr. Paul Tambyah, the trial's lead investigator. "The results of this first INV21 clinical trial are very promising," he said.
Dr. Tambyah is associate professor of the Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore and senior consultant with the Division of Infectious Diseases at the National University Hospital. These institutions, along with Duke University, are partnering with Inviragen on the HFMD program.
Tambyah said this first clinical trial was a randomized, placebo-controlled study. Thirty-six healthy adults received two immunizations of either a high- or low-dose INV21 vaccine. They were monitored for any adverse reactions and tested for antibodies that neutralize the EV71 virus. Not only did all the individuals who received the vaccine have significantly increased EV71 immune responses, the INV21 was well tolerated by study participants.
Inviragen will present safety and immunogenicity data from the trial at an infectious disease meeting later this year, said Dr. Dan Stinchcomb, Inviragen's co-founder and CEO. Now confident regarding the vaccine's safety, researchers are planning a larger clinical trial within the year. Phase 2 will likely enroll hundreds of participants, among them children ages 1-5, because it's the population hardest hit by the disease.
As of mid-May, over 43,000 Vietnamese were diagnosed with HFMD -- mostly young children -- 22 of whom died. Eighty-six percent were under 3 years old, according to information released through the country's Health Ministry. Last year, more than 110,000 Vietnamese contracted HFMD and 166 children died.
Similarly, in the first nine weeks of 2012, the number of HFMD cases in Singapore rose past the epidemic threshold as defined by the Ministry of Health. Nearly 6,000 cases were reported, compared to fewer than 2,000 during the same period in 2011. This spring in Malyasia, 35 pre-school and child care centers had to be closed in the state of Sarawak in an effort to break the cycle of transmission. In April, 20,000 cases were diagnosed in the Hunan Province of China--more than three times higher than in March; 19 children died.
Especially troubling to health care professionals is that they are seeing a more virulent strain of HFMD, associated with such serious neurological side effects such as meningitis, encephalitis, polio-like paralysis and death. In fact, enterovirus 71 (EV71) has been identified as the most dangerous and deadly of the viruses that cause HFMD.
Inviragen's INV21 formula specifically targets EV71. Currently, no other vaccines or therapies exist so physicians in affected countries are watching the vaccine's development with avid interest, especially as the decade-long surge in cases continues.
"INV21 is an inactivated viral particle vaccine," explained Dr. Stinchcomb, "This means that the outer coat of the virus is intact but the internal functions that allow a virus to replicate have been removed."
Unlike mosquito-borne diseases such as dengue and chikungunya, HFMD is transmitted person-to-person through direct contact or contact with contaminated surfaces, and incidence seems to increase during periods of high humidity and flooding.
The INV21 vaccine is produced in a mammalian cell line known as "Vero" that has been widely used in vaccine production for decades. "Vero cell culture permits rapid and reproducible scaling to large quantities of vaccine," said Dr. Stinchcomb. " We use a proprietary EV71 strain to produce our vaccine that grows well in Vero cells and can generate immune responses to several commonly occurring strains of EV71."
Inviragen is also developing vaccines effective against dengue fever, chikungunya, Japanese encephalitis, human papilloma virus, influenza, and a combination plague/smallpox vaccine for biodefense. Viral strains or viral vaccines are sequenced to provide genetic assurance of safety and efficacy.
The Colorado-based company, launched in 2006, has expanded its operations to include offices in Singapore and Wisconsin. Inviragen is the recipient of a $15.5 million grant from the National Institutes of Health for its needle-free vaccine offering protection against dengue virus, a disease that causes 20,000-plus deaths annually. For more information, log onto www.inviragen.com.