Protein Sciences Announces FDA Clearance to Conduct Proof of Principle/Field Trial of FluBlok(TM), its Cell-Culture Influenza Vaccine

MERIDEN, Conn. -- Protein Sciences Corporation announced today that it had received FDA clearance to conduct a Phase II/III proof of principle/field study of FluBlok(TM), its patented cell culture influenza vaccine. The randomized, double blind, placebo controlled trial will be conducted in subjects aged 18-49 and will compare two different doses of FluBlok with a placebo group. The primary endpoints are to show safety and establish a commercial dose for FluBlok. A secondary endpoint is to establish efficacy under field conditions, which the study is powered to demonstrate with statistical significance if the influenza season is relatively robust. The study sites are the University of Rochester, NY (Dr. John Treanor, Study Principal Investigator), the University of Cincinnati Children's Hospital (Dr. Gilbert Schiff) and the University of Virginia (Dr. Frederick Hayden).

Daniel D. Adams, president and CEO of Protein Sciences stated, "This is a very exciting time for us. Recent events highlight the critical need for influenza vaccines made using modern technology and cell culture. We believe that FluBlok is the only vaccine under development that can resolve all of the issues associated with the licensed egg-grown vaccines and therefore can address the entire potential market, estimated at more than $4 billion, for influenza vaccines. If this trial is successful, we plan to move immediately into a pivotal trial that we expect will lead to licensure. However, unfolding events may speed up the process. He added, "Recent events have highlighted our dependence on foreign companies for our influenza vaccines. We are, therefore, exceptionally well-positioned because we are the only U.S. company with a cell culture influenza vaccine in late stage clinical trials, the only company conducting a late stage cell culture vaccine trial in the U.S. and the only company to have a potential pandemic vaccine tested in humans."

FluBlok is like the licensed egg-grown vaccines because it contains antigens (hemagglutinin proteins) that are derived from three strains of the influenza virus that are selected for inclusion in the annual influenza vaccine by the CDC and the FDA. FluBlok presents a potential solution to the multitude of issues associated with the licensed vaccines that are grown in eggs. FluBlok's antigens are developed using recombinant DNA technology and manufactured in cell culture without eggs. Unlike the licensed vaccines and many cell culture vaccines in development, no live influenza viruses, biocontainment facilities or harsh chemicals such as formaldehyde are used in manufacturing. FluBlok consists solely of three antigens (proteins) stored in sterile buffered salt water and without preservatives such as thimerosal, a mercury derivative currently used in egg-production, or adjuvants. New FluBlok vaccines can be developed quickly and safely to address late appearing influenza viruses such as A Fujian in 2003-2004 and emerging natural or man- made pandemic viruses, as evidenced by Protein Sciences' achievement in making a vaccine for the 1997-1998 Hong Kong bird flu in just eight weeks.

The 2004-2005 trial is being funded by the Company from its revenues, although the Company is raising additional capital through Credit Suisse First Boston to support future trials and commercial manufacturing. Seven previous clinical trials of FluBlok, all of which were sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), a division of the National Institutes of Health, showed safety and generation of antibody titers that are accepted as being protective against influenza. The latest trial was conducted in approximately 400 elderly subjects in 2003-2004 and compared a licensed egg-grown vaccine with three different doses of FluBlok containing the same hemagglutinin antigens. The data showed that all doses of FluBlok were safe and achieved antibody levels that are believed to be associated with better protection against an H3 influenza virus(1) than subjects receiving the licensed vaccine. Historically, 30 percent to 50 percent of elderly subjects vaccinated with the licensed vaccines achieve protective titers against the H3 strain and, therefore, the goal was to show that at least 50 percent to 70 percent (20 percent more) of subjects vaccinated with FluBlok would achieve protective titers. Subjects receiving the highest doses of FluBlok exceeded the 20 percent goal -- 77 percent and 97 percent, respectively, of the subjects achieved protective titers as measured by Geometric Mean Titer, a common measure of vaccine effectiveness. Three additional studies over the next 12 months have been committed to by NIAID: one in B cell lymphoma patients that is underway; one using the Company's H5N1 -- A Vietnam "bird flu" vaccine and a follow-on trial in the elderly that will involve revaccination and pre-vaccination stratification for antibody levels.

(1) The H3 strain causes the majority of the 20,000 to 70,000 excess influenza-related deaths each year in the U.S., more than 90% of which occur in the elderly. In the 2003-2004 influenza vaccine was A Panama and in the 2004-2005 vaccine was changed to A Wyoming.

Source: Protein Sciences Corporation

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