NOVAVAX Reports Positive Results From Phase I Trial of Respiratory Syncytial Virus Vaccine Candidate

Gaithersburg, Maryland, UNITED STATES

Well-tolerated with no systemic side-effect trends
Highly immunogenic with an increase in anti-RSV antibodies in 100% of subjects in the highest-dose group
Oral and poster presentations to be made at 5th Vaccine and ISV Annual Global Conference in Seattle

ROCKVILLE, Md., Oct. 3, 2011 (GLOBE NEWSWIRE) -- Novavax, Inc. (Nasdaq:NVAX) today announced positive top-line results from a Phase I clinical study of its respiratory syncytial virus (RSV) fusion (F) recombinant nanoparticle vaccine candidate. In a paper titled "Recombinant RSV F nanoparticle vaccine for respiratory disease: antigen characterization, preclinical efficacy and clinical evaluation," Gregory M. Glenn, M.D., Senior Vice President and Chief Medical Officer of Novavax, is presenting safety, immunogenicity and tolerability findings from this study in a poster and oral presentation today and tomorrow, respectively, at the 5th Vaccine and ISV Annual Global Conference in Seattle. In the United States, RSV is the most common cause of bronchiolitis and pneumonia in children under 1 year of age resulting in 90,000 to 147,000 hospitalizations in this age group. Additionally, 900,000 adult and elderly patients are hospitalized annually due to RSV infection in the United States and Europe.

Novavax initiated the blinded, placebo-controlled, dose-escalating Phase I trial in December 2010 to assess the safety and tolerability of aluminum phosphate-adjuvanted (adjuvant) and unadjuvanted formulations of its RSV vaccine candidate. A secondary objective of the study was to evaluate total and neutralizing anti-RSV antibody responses and assess the impact of the adjuvant. The study enrolled 150 healthy adults 18 to 49 years old who were allocated to six cohorts that included 4 dose levels of vaccine. The two highest dose levels were formulated with and without the adjuvant. Subjects were randomized to receive injections of vaccine or saline placebo in a 4:1 ratio on days 0 and 30. Immune responses were evaluated in blood samples taken on days 0, 30, and 60.

"The results from our first RSV in-human study are very encouraging and support expanded testing of this vaccine candidate to those most affected by RSV infection, infants and children, and adults age 65 and older," Dr. Glenn said. "Our findings from this Phase I trial are consistent with our preclinical results in relevant animal models, which indicated that our vaccine candidate was generally well-tolerated, highly immunogenic and produced functional antibodies that neutralized RSV. In the same preclinical studies, the vaccine was fully protective against live-virus challenge, indicating that such measures of immunity are associated with protection. RSV disease is a major unmet medical need and a priority target for vaccine developers, and the results from this trial represent an important step towards reaching the ultimate goal of a safe and effective vaccine."

In his presentations, Dr. Glenn is reporting that Novavax's RSV vaccine candidate was well-tolerated and highly immunogenic, inducing levels of functional immunity that could potentially correlate with protective immunity in future trials. The fusion (F) antigen used in the Novavax RSV vaccine candidate is common to all RSV strains. Antibodies against the F antigen are known to prevent RSV disease in premature infants using the injected monoclonal antibody Synagis® (palivizumab), the current standard of care for RSV prophylaxis in premature infants. The data seen in this trial indicate that the Novavax RSV vaccine candidate induces immunity similar to natural protective immunity, as well as induces responses against the specific molecular target of Synagis on the F protein. Together, these data suggest that the vaccine may hold promise for prevention of RSV illness.

The primary safety findings were local pain and tenderness at the site of injection, the majority of which were mild in nature with no dose-related increase observed. There were no observed vaccine-related serious adverse events or trends for related systemic side effects. The antibody response to the RSV F protein was significantly increased compared to placebo (p<0.001) in all groups and increased by 19 fold in the highest-dose group at day 60. A significant dose-response pattern was observed. High rates of seroconversion were seen at all doses including a rate of 100% at the highest-dose-adjuvant group. Plaque reduction neutralizing titers (PRNT) were also measured and were significantly higher (p<0.01) in all the vaccine groups containing adjuvant. Exploratory measures of the vaccine-generated immunity specific to the Synagis epitope on the RSV F protein indicated that the vaccine induced significant increases (p<0.0001) compared to placebo in all groups.

Stanley C. Erck, President and Chief Executive Officer of Novavax, stated: "I congratulate my colleagues and our clinical investigators on these impressive results which will allow us to continue to pursue the development of a vaccine to prevent RSV infection. There remains an urgent public health need for such a vaccine, as none exist today and current treatments for RSV are expensive, difficult to administer and of limited benefit. We believe our vaccine candidate shows great promise as a potential prophylactic against RSV lower respiratory tract illness. The clinical data from this trial now provides a pathway for us to aggressively move forward in studying this vaccine candidate in infants, young children and older adults who represent the populations most affected by RSV."

About Respiratory Syncytial Virus

RSV is the most important viral cause of lower respiratory tract infection in infants and children worldwide. The global disease burden is estimated at 64 million cases and 160,000 deaths every year. RSV is the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia in children under 1 year of age in the United States. Each year, 90,000 to 147,000 children in this age group are hospitalized due to RSV infection. Almost all children will have had an RSV infection by their second birthday. When infants and children are exposed to RSV for the first time, 25% to 40% of them have signs or symptoms of bronchiolitis or pneumonia, and 0.5% to 2% will require hospitalization. Most children hospitalized for RSV infection are under 6 months of age. Additionally, wheezing illnesses caused by RSV, particularly those severe enough to lead to hospitalization, are associated with an increased risk of asthma at school age.

It is also estimated that more than 8.5 million adults, including the elderly over age 65 years, are infected and 900,000 patients are hospitalized annually due to RSV infection in the United States and major European countries. In the United States alone there are 177,500 hospitalizations among high-risk adults resulting in annual medical costs exceeding $1 billion. There is currently no approved vaccine for the prevention of RSV.

About Novavax

Novavax, Inc. (Nasdaq:NVAX) is a clinical-stage biopharmaceutical company creating novel vaccines to address a broad range of infectious diseases worldwide. Using innovative virus-like particle (VLP) and recombinant nanoparticle technology, as well as new and efficient manufacturing approaches, the company produces potent vaccine candidates to combat diseases, with the goal of allowing countries to better prepare for and more effectively respond to rapidly spreading infections. Novavax is committed to using its technology platforms to create geographic-specific vaccine solutions and is therefore involved in several international partnerships, including collaborations with Cadila Pharmaceuticals of India and LG Life Sciences of Korea. Together, these companies have worldwide commercialization capacity and the global reach to create real and lasting change in the biopharmaceutical field. Additional information about Novavax is available on the company's website:

Forward Looking Statements

Statements herein relating to the future of Novavax and its ongoing development of its vaccine candidates, including statements related to clinical results, are forward-looking statements. Novavax cautions that these forward-looking statements are subject to numerous risks and uncertainties, which could cause actual results to differ materially from those expressed or implied by such statements. These risks and uncertainties include those identified under the heading "Risk Factors" in the Novavax Annual Report on Form 10-K for the year ended December 31, 2010, and filed with the Securities and Exchange Commission. We caution investors not to place considerable reliance on the forward-looking statements contained in this press release. You are encouraged to read our filings with the SEC, available at, for a discussion of these and other risks and uncertainties. The forward-looking statements in this press release speak only as of the date of this document, and we undertake no obligation to update or revise any of the statements. Our business is subject to substantial risks and uncertainties, including those referenced above. Investors, potential investors, and others should give careful consideration to these risks and uncertainties.

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