Interfax:China-made bird flu vaccine proven safe during phase I clinical trial

Shanghai. August 28. INTERFAX-CHINA - The preliminary results of Phase I clinical trials for the Pandemic Influenza Vaccine (H5N1) showed that the vaccine is safe and effective, Sinovac Biotech Ltd., one of the vaccine's developers, announced on Monday.

The result proves that the vaccine with different dosages can induce immune responses, with the vaccine containing 10 ug antigen shown to have the best immunogenicity with a sero positive rate of 78.3%, exceeding the EU CHMP criteria for seasonal influenza vaccines (≥70%).

The Blood Routing Test, Clinical Biochemistry Test, Urine Routing Test, and the observations of systemic and local adverse reactions showed that the vaccine is well-tolerated and immunogenic, and there was no serious adverse event reported by the 120 volunteers.

The bird flu vaccine, supported by the Ministry of Science and Technology, is co-developed by the Chinese Center for Disease Control and Prevention (CDC) and Sinovac Biotech Ltd.

Sinovac started clinical trials of its proprietary Pandemic Influenza Vaccine (H5N1) last November. Six volunteers in the first group were vaccinated on December 21, and the code-breaking procedure of the randomized and double-blinded Phase I clinical trial was completed last June.

The Pandemic Influenza Vaccine is an inactivated whole virion vaccine, and the virus strain used is NIBRG-14, which was recommended and provided by World Health Organization (WHO). The virus strain was a reassortant strain prepared using reverse genetics, which is non-pathogenic. The vaccine is adjuvanted with aluminum hydroxide, which can enhance the vaccine's immunogenicity to human bodies, reduce the antigen content for certain level of immunogenicity.

In an earlier interview with Interfax, Gao Hong, a researcher with Sinoivac, said, "Once the H5N1 virus mutates, we can change new virus strains based on the pandemic flu vaccine, and develop a new one. The vaccines developed before the virus mutates also have certain degree of protection over people. For example, an H5N3 vaccine was also effective to some degree in preventing H5N1 in Hong Kong several years ago. And so it is important to develop vaccines before the virus mutates."

Lu Zhengyou, a PR official with Sinovac, told Interfax that "now we are preparing for the application for Phase II clinical trials for Pandemic Influenza Vaccine (H5N1) with the Chinese Center for Disease Control and Prevention".

The SFDA fast-tracked the approval procedure for the phase I clinical trial of the vaccine, but the company is not sure whether the SFDA will fast track the approval for phase II clinical trial, Lu added.

The company said that if clinical trials are successful, its estimated production capacity may be as high as 20 mln doses per year using its current manufacturing facilities.

The development of bird flu vaccines is underway throughout the globe. Pasteur in the US and France, CSL in Australia, GSK, some companies in Russia and certain European countries are all conducting clinical trials for various bird flu vaccines.

Sinovac Biotech Ltd. focuses on the R&D, manufacture and commercialization of vaccines for endemic and pandemic viruses such as hepatitis and influenza, and for fast emerging viruses such as SARS and avian influenza. Sinovac partnered with Beijing Sino-Japan Friendship Hospital for the successful Phase I SARS clinical trials in 2004.