“FluBlØk: A Recombinant Hemagglutinin Protein Vaccine for Influenza” Manon Cox VRBPAC February 27, 2007 A Vaccine Company for the 21st Century “Making products where speed, cost and safety matters” Influenza Vaccines for pre-pandemic uses

FluBlØk™ - Next Generation Vaccine for Influenza ”Making products where speed, cost and safety matters” Trivalent recombinant HA (rHA) antigen vaccine Produced in vitro via insect cell culture technology Produced in vitro via insect cell culture technology Cloned from WHO/CDC recommended strains Cloned from WHO/CDC recommended strains Easier to produce, no eggs, no live viruses, no bio-containment required, no preservatives Easier to produce, no eggs, no live viruses, no bio-containment required, no preservatives FluBlØk rHA Antigens: Highly purified (>95%) Highly purified (>95%) Correct 3-D structure Correct 3-D structure Biologically active Biologically active Hemagglutinin activity Hemagglutinin activity Induces protective immune responses Induces protective immune responses HAI antibodies HAI antibodies Neutralizing antibodies Neutralizing antibodies

Production and testing of a vaccine against Potential Pandemic Flu – Hong Kong “Bird Flu” Time required for development and production Time required for development and production  Six weeks from gene to product  Eight weeks from gene into humans  Fully protected chickens against a lethal challenge  200 healthcare workers and researchers – protective titers  The first pandemic influenza vaccine in clinical trials Safety during production Safety during production  No need to grow or handle a live virus  Use of a well defined cell line versus egg production  Enormous surge capacity:  Estimated worldwide capacity for mammalian cell culture is 2.5 M liters  1M doses of 135μg per 10,000L in 5-day production cycle  …. feasible to produce billions of doses in a matter of weeks Authenticity of the antigen Authenticity of the antigen  Antigen in vaccine is an exact match to natural H5N1 virus  No exchange of basic amino acids and potential introduction of changes to the antigen

Production of a HA vaccine against any emerging influenza strain Pandemic Influenza ≠ H5 alone….. YearStrain Impact + Location 1997H5N1 18 (6) Hong Kong 1998H9N25China 1999H9N H7N21 US Virginia 2003H5N1H7N7H9N2 4 (4) 89 (1) 1AsiaNetherlands Hong Kong 2004H5N1H7N3 46 (32) 2AsiaCanada 2005H5N1 97 (42) Asia 2006 ‡ H5N1 114 (79) Asia/Middle East/ Africa? + ( * ) = deaths ‡ as of 12/27/06

Four additional hemagglutinin antigens (H2, H5, H7 and H9) have been cloned from strains with pandemic potential and were produced using a general HA purification process. Recombinant protein-based influenza vaccine is the most vital pro-active approach in fighting against a potential influenza pandemic! (surge capacity is enormous – large production capacity available; speed; no yield problem observed with H5) PSC plans to produce & market a prophylactic pandemic vaccine after approval of FluBlØk Pandemic influenza in general “ Protein Sciences preparedness plan ”

FluBlØk Clinical Development Ongoing clinical studies PSC02: Evaluation of the Safety, Reactogenicity and Immunogenicity of FluBlØk Trivalent Recombinant Baculovirus-Expressed Hemagglutinin Influenza Vaccine Administered Intramuscularly To Healthy Children Aged 6 to 59 Months Results expected in Q PSC03: Comparison of the Immunogenicity, Safety and Reactogenicity of FluBlØk, Trivalent Recombinant Baculovirus-Expressed Hemagglutinin Influenza Vaccine, To a Licensed Egg-Grown Influenza Vaccine In Ambulatory Elderly Adults Results expected in Q2 2007

FluBlØk Phase II/III Field Study Summary of Results n Commercial dose Efficacy: 100% (even against drifted H3 strain) Efficacy: 100% (even against drifted H3 strain) Effectiveness: Effectiveness: 54% reduction (p ) in CDC-ILI vs. placebo 54% reduction (p ≤0.05) in CDC-ILI vs. placebo n Efficacious and effective without neuraminidase n Highly immunogenic H3 component - high and long lasting titers H3 component - high and long lasting titers Protective levels for all antigens for at least 6 months Protective levels for all antigens for at least 6 months n FluBlØk protects against “drifted” strains

FluBlØk vs. FluZone Phase II(b) Trial in Elderly - H3 Antigen % of subjects 75 years and older % of all subjects Subjects achieving Titer ≥ 1:128 against H3 HA Component (Treanor et al., 2006) 399 subjects; low, medium (commercial), high dose FluBlØk; TIV Very High Titers in Elderly, Including Very Old

FluBlØk™ - Next Generation Vaccine for Influenza ”Making products where speed, cost and safety matters” The BEVS technology provides:  Speed, Cost and Safety   Rapid response to emerging strains  No need to handle live influenza viruses  Authentic antigen (no changes due to adaptation of the virus to egg or cell culture) Next Steps:  Two clinical studies ongoing now  Efficacy study in healthy adults scheduled for influenza season  BLA filing expected Q  Development of prophylactic pandemic vaccine in 2009