Another New Bird Flu Vaccine Shows Promise

A Rockville, Maryland-based biotech company, Novavax Inc., has released successful results of human safety trials for a new type of bird flu vaccine. The vaccine uses a simulated form of the flu virus that seems to offer human protection against infection of H5N1 avian influenza and has been deemed safe enough to move forward with further testing. The vaccine appears to work as well as other vaccines that are in various stages of development for prevention of the bird flu.

Initially, GlaxoSmithKline (GSK), the biggest drug maker in Europe, was given the green light from the European Commission for the first human vaccine against H5N1 bird flu. The vaccine, Prepandrix, activates an immune response to the H5N1 strain of bird flu and contains a special additive that allows a very low dose of active ingredient to be used in each shot. It is the first vaccine to receive a license for use in the 27-member EU region. The vaccine could offer a degree of protection until a more precisely tailored pandemic vaccine could be produced, which could take 4-6 months from the time a pandemic strain is identified.

In June of this year, scientists released trial results on a new vaccine manufactured by Baxter International, Inc. known as Celvapan, which is developed using monkey cells grown in labs that appear to be safe and effective and can be manufactured in only about 12 weeks.

Following closely behind in July, Vical Incorporated also announced a newly developed DNA-based vaccine for the H5N1 avian flu that had the capability of safely stimulating the immune system and protecting against flu in their preliminary trials. These vaccines can be made in six to eight weeks using bits of genetic material (plasmids) to create an immune response against a specific part of the virus.

Now, according to Novavax President and Chief Executive Officer Dr. Rahul Singhvi in a conference call for investors, the trial results for this latest vaccine are strong and very competitive and compare well with any vaccine against pandemic flu, whether licensed or in development.

Influenza vaccines commonly use a live but weakened flu virus or even a dead virus to stimulate the immune system. They are annually reformulated in an attempt to match mutating strains. In addition, they are created in specially grown live chicken eggs and take months to make.

Novavax grows the vaccine in lab dishes of caterpillar cells using a mock version of the virus that is a virus-like particle. Singhvi said that it looks like the virus in that it has the same size and shape as the virus but it lacks the genes needed to replicate. It is not a virus but the body views it as a virus. The company believes the manufacturing process will be much quicker than current technology although several companies and groups are working to develop a vaccine to protect against H5N1.

Dr. Robert Belshe of the Saint Louis University School of Medicine in Missouri, who served on the Data and Safety Monitoring Board for the study, said in a statement, "Two doses of this novel vaccine, which is designed to prevent bird flu, gave strong immune responses. The data are encouraging that this new vaccine approach can help prevent pandemic influenza."

In the study, 160 patients received two injections in doses ranging from 15 to 90 micrograms. At the highest dose, the vaccine produced a response against one version of the H5N1 bird flu in 94 percent of patients.

There have been outbreaks of the H5N1 avian influenza virus spreading from birds to humans in 15 countries that have killed 243 out of 385 people infected since 2003 according to the World Health Organization. The virus is quickly spreading through poultry in Asia, Europe, the Middle East and Africa and it is believed the bird flu could mutate into a form more infectious to humans.

Novavax's chief medical officer Dr. Penny Heaton indicated that the company would proceed with clinical development when a partner is found. The company will start testing a seasonal flu vaccine later in the year and will submit its findings to the peer-review system of medical journals and meetings.