NOVAVAX Reports on Progress with RSV Vaccine at New International Conference on Modern Vaccines
Dr. Glenn stated during his presentation: "The past development of an RSV vaccine has been very challenging to the vaccine industry. In reviewing our clinical and preclinical data, we recently uncovered some important insights about natural infection by RSV that should assist us in the development of an effective vaccine. These insights include:
"In both clinical and preclinical studies, we found that while subjects exposed to RSV infections had anti-F antibodies, there are almost no antibodies to a specific antigenic site (site II) on the highly conserved Fusion (F) protein of RSV. "In clinical studies, a monoclonal antibody that targets the antigenic site II (i.e., palivizumab) has been shown to be highly effective at preventing RSV disease. In fact, palivizumab (trade name Synagis®) has been approved in multiple countries for years to prevent RSV disease in pre-mature infants. "Together, these data points suggest a survival advantage for the RSV virus based on keeping the RSV F antigenic site II cryptic during natural infections, and that the antigenic site II specific immunity can be exploited for an effective vaccine."
Dr. Glenn went on to add: "Immunization with the Novavax RSV F nanoparticle vaccine antigen, which contains multiple copies of the antigenic site II epitope, induced robust antigenic site II specific antibodies in both our preclinical and clinical studies. In preclinical studies, immunization of cotton rats with RSV F nanoparticles induced anti-RSV IgG that was neutralizing, competitive for the binding of palivizumab to RSV F, and was completely protective against viral challenge.
"Similarly, in a Phase I placebo-controlled trial, the same vaccine given to healthy adults induced both RSV A and B microneutralizing antibodies that were significantly increased in vaccinees versus placebo and in excess of what has been observed to be protective in other epidemiological studies. Antibodies that both bind to and compete with the F protein antigenic site II were readily induced by the vaccine. Quantitative estimation of palivizumab-like activity found the highest dose group had a mean of 335 µg/ml, exceeding by around 10-fold the trough level used as guidance in palivizumab efficacy evaluations.
"The Novavax RSV F nanoparticle vaccine candidate displays the antigenic site II epitope in its native configuration and was found to induce functional immunity as measured both by microneutralization and palivizumab-like antibodies at levels that exceed those associated with decreased risk of hospitalization. Together, the results suggest that our RSV F nanoparticle vaccine holds great promise as a vaccine candidate for infants, children and the elderly who would benefit from protective immunity against RSV."
Dr. Glenn's plenary presentation, entitled "Recombinant nanoparticle vaccine: Preclinical and clinical evaluation of an Sf9 insect cell-derived respiratory syncytial virus fusion protein," is available in the Our Science/Presentations tab of the company's website, www.novavax.com. Dr. Glenn also served as a scientific advisor to the conference, which was organized to address the urgent need for new adjuvants, delivery systems and technologies to support the development of new vaccines. For more information about the conference, please visit www.meetingsmanagement.co.uk.
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Frederick W. DriscollVP, Chief Financial Officer and Treasurer Novavax, Inc.240-268-2000