NIH Tests H7N9 Avian Flu Vaccine
Researchers investigate possible role for adjuvants (September 18)
Researchers at nine sites nationwide have begun testing in humans an investigational H7N9 avian influenza vaccine. The two concurrent phase II clinical trials, sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), are designed to gather critical information about the safety of the candidate vaccine and the immune system responses it induces when administered at different dosages and with or without adjuvants (substances designed to boost the body’s immune response to vaccination).
Human cases of H7N9 influenza first emerged in China in February 2013. As of August 12, 135 confirmed human cases, including 44 deaths, have been reported by the World Health Organization. Most of these cases involved people who came into contact with infected poultry. Although no H7N9 influenza cases have been reported outside of China and the virus has not demonstrated sustained person-to-person transmission, there is concern that it could mutate to pose a much greater public health threat.
The two clinical trials, which will enroll healthy adults aged 19 to 64 years, will evaluate an investigational H7N9 vaccine developed by Sanofi Pasteur. The candidate vaccine was made from inactivated H7N9 virus isolated in Shanghai, China, in 2013. Adjuvants are being tested with the investigational vaccine because previous vaccine research involving other H7 influenza viruses has suggested that two doses of vaccine without adjuvant may not produce an immune response adequate to provide effective protection.
The first clinical trial will enroll up to 700 study participants, who will be randomly assigned to one of seven groups. Each group will receive two equivalent doses (3.75 mcg, 7.5 mcg, 15 mcg, or 45 mcg) of the candidate vaccine approximately 21 days apart. In addition, five of the groups will receive the vaccinations along with MF59 adjuvant, developed by Novartis Vaccines and Diagnostics.
The second trial will enroll up to 1,000 participants. Each participant will be randomly assigned to one of 10 groups and will receive two equivalent doses (same doses as the other trial) of the investigational H7N9 vaccine given 21 days apart.
Seven of these groups will receive the vaccinations either with or without AS03 adjuvant, developed by GlaxoSmithKline Biologics. Two groups will receive their first vaccination with AS03 or MF59 adjuvant and will then receive the alternate adjuvant at the time of the second vaccination. One group will receive the MF59 adjuvant at both vaccinations. The AS03 adjuvant that is being tested was used in an H1N1 influenza vaccine, Pandemrix, during the 2009–2010 H1N1 influenza pandemic in Europe.
Both studies are expected to conclude in December 2014.
Source: NIH; September 18, 2013.