At the recent World Vaccine Congress in Washington, DC, biotechnology company Novavax, Inc. held 2 presentations on trials for new vaccines for respiratory syncytial virus (RSV) and influenza virus.
Most children have had an RSV infection by their second birthday, according to the Centers for Disease Control and Prevention (CDC). The virus is common and causes symptoms including a runny nose, coughing, sneezing, fever, wheezing, and a decrease in appetite. While symptoms are usually mild and pass within a week or two, more severe cases of RSV can lead to bronchiolitis or pneumonia and can be serious in young infants or older adults. More than 57,000 children under the age of 5 and 177,000 older adults in the United States are hospitalized for RSV each year. There is currently no vaccine available for the virus, and in most cases, symptoms can be managed with over-the-counter fever reducers and pain relievers.
With flu season waning in the United States, health officials have been responding to concerns over the flu vaccine’s low rate of effectiveness in preventing flu illness. Flu vaccination coverage rates continue to remain below health officials’ overall target of 70% for individuals age 6 months and older, and boosting the effectiveness of the flu shot has become a public health priority. The vaccine’s poor performance – particularly with influenza A (H3N2) – is in part due to the egg-based vaccine production that researchers have found makes the vaccine components prone to mutation. Alternatives to egg-based vaccines, such as cell-based vaccine production, have yielded more effective vaccines, while scientists continue to work on the development of a universal flu vaccine which would offer protection across several seasons.
At the recent World Vaccine Congress held in Washington, DC, representatives from Novavax gave presentations on progress for the company’s 2 lead vaccine programs, involving the development of vaccine candidates for RSV and the flu. Novavax’s RSV F Nanoparticle vaccine is intended for maternal immunization during pregnancy, offering protection for infants through placental antibody transfer. The Bill and Melinda Gates Foundation has worked in collaboration with Novavax on the vaccine, and the company says that its Phase 3 Prepare trial may conclude in less than 12 months.
“While mortality related to RSV in infants is low in industrialized countries, in the developing world RSV is second only to malaria as a cause of infant death,” said Novavax CEO Stan Erck in a recent interview with Contagion®. “Since the infant immune system is immature and would require several vaccine doses to mount an effective immune response, Novavax’s strategy is to provide protection to the infant under 6 months of age with antibodies produced by immunizing the mother and passed to the developing fetus through the placenta – a natural physiologic process that has been shown effective against tetanus, pertussis and influenza.”
In addition, Novavax representatives also presented data from the Phase 1/2 trial of 2 trivalent formulations of its NanoFlu vaccine, which uses the flu strains recommended by the CDC and World Health Organization (WHO) and Novavax’s proprietary saponin-based Matrix-M adjuvant. Unlike currently available licensed egg-based flu vaccines, said Erck, the recombinant hemagglutinin proteins (HA) contained in NanoFlu reflect the wild-type sequences of the influenza viruses actually circulating in the community and thereby avoids the problems of egg-adapted mutations in HA known to arise from the egg-based flu vaccine production process.
“In our recent Phase I/II trial, we observed that the higher dose of NanoFlu outperformed the market leading Fluzone-HD vaccine (a flu vaccine specifically indicated for older adults) on classical immunogenicity measures (hemagglutinin-inhibition antibodies or HAI) against both A(H3N2) strains contained in the vaccine (by 47%), and against forward drifted or forward evolved A(H3N2) strains (by 61%),” Erck said. “We believe this significant improvement in immune responses is due to both avoidance of the egg-adapted mutations seen with egg-produced vaccines and because NanoFlu is likely to induce broader immune responses against both the A(H3N2) strain contained in the vaccine and against those strains that are antigenically drifted (mismatched) to the vaccine.”
Novavax expects to further test the Nanoflu vaccine this fall and potentially perform a pivotal licensing trial starting in the fall of 2019.
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