The Duke Early Phase Clinical Research (DEPRU) recently completed the first study cohort for a broad-spectrum investigational influenza vaccine that has the potential to be effective against multiple strains of the virus for five or more years at a time.
Thirty-seven adult study volunteers, 22 of whom were confined in the unit simultaneously for approximately one week, will be followed for 15 months after immunization as part of the multi-center, randomized, observer-blind phase I safety and immunogenicity study. The volunteers are part of a larger group of up to 55 volunteers spread across two clinical sites at the DEPRU and Cincinnati Children’s Hospital Medical Center. The study is sponsored by the international nonprofit PATH, and the investigational vaccine was developed through a partnership between the Icahn School of Medicine at Mount Sinai (ISMMS) and PATH, the study’s sponsor.
“There are several reasons why you get an influenza vaccine every year,” said Chip Walter, MD, Duke Clinical Vaccine Unit director and co-investigator on the study. “One is that strains change from year to year and the protection isn’t durable. I think this is a step toward finding a vaccine that is broadly cross-protective. If the technology is successful, the vaccine will protect against seasonal influenza strains and pandemic influenza strains that jump species from animals to humans.”
The United States is in the midst of its worst influenza season in almost a decade. Although most people will make a recovery within a week, there has been a large number of hospitalizations and pediatric deaths this season. The annual influenza vaccine can provide protection to those who get it before they are exposed to the virus. However, the effectiveness of the vaccine depends on whether it is properly matched against the season’s circulating strains of the virus.
Current vaccines are designed to create antibodies to specific strains of the virus to build the body’s immunity before they strike. This is one of the reasons why the effectiveness of the annual vaccines can range from 60 percent to 10 percent. Once an individual has been exposed to the virus, it enters the respiratory tract cells via a protein on the surface known as the hemagglutinin molecule, the universal vehicle among influenza strains.
Researchers say the vaccine could be effective against multiple strains of the virus for several years.
Developed at ISMMS, the investigational vaccine utilizes a technology which combines two different protein segments of the hemagglutinin to engineer a new protein. This new, chimeric hemagglutinin redirects the immune system to target sites that are conserved and do not change every year. The study has five treatment groups testing two different combinations of a live [Jeff Guptill] attenuated virus, which is a weaker form of the virus, and an inactivated split influenza vaccine with or without an adjuvant to potentially boost immune response.