Novartis MF59®-adjuvanted vaccine rapidly induces protective antibody levels against diverse strains of avian flu
29-SEP-2008 Intellasia | Medical News Today
Sep 29, 2008 - 7:00:00 AM
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A new study shows that individuals immunised six-years earlier with an MF59 adjuvanted H5N3 (clade 0) vaccine mounted a protective immune response seven days after a single immunisation with an H5N1 (clade 1) vaccine containing the Novartis proprietary adjuvant MF59. The immune response was broadly cross reactive and covered all H5N1 clades known to date. These data were presented at the Third European Influenza Conference in Vilamoura, Portugal.
Responses were seen even against viral strains not included in either vaccine[1] suggesting proactive priming strategies with an MF59 adjuvanted-H5 vaccine may have the potential to help save lives in an avian influenza pandemic situation.
"These data highlight the potential for priming the public against an avian influenza of pandemic proportion with the MF59 adjuvant. The results indicate that regardless of which avian strain individuals are originally primed with, they are quickly protected against a broad range of avian strains following their MF59-adjuvanted booster vaccine, even strains they were not initially inoculated against," said study investigator Iain Stephenson M.R.C.P., Infectious Diseases Unit, University Hospitals Leicester and Department of Inflammation, Infection and Immunity, University of Leicester, UK.
"These results potentially provide a rationale to prevent pandemic influenza by proactively immunising the public with stockpiled pre-pandemic vaccines containing MF59," Dr Stephenson added. According to the trial results, healthy adults primed with an MF59-adjuvanted H5 vaccine at least 6 years ago, and boosted with the Novartis pre-pandemic vaccine AFLUNOV (7.5microgram MF59-adjuvanted A/Vietnam/1194/2005 clade 1 H5N1), showed a protective cross-reacting antibody response to diverse H5N1 virus variants. Response was seen within 7 days and results were significantly higher (P< 0.05) at 14 days than those primed with a un-adjuvanted vaccine[1]. In addition, these study results suggest primed individuals would only need one dose of an MF59-adjuvanted vaccine in a pandemic situation to elicit initial protection reducing overall response time, and potentially the spread of the virus[1].
"These findings show that priming subjects with the Novartis proprietary adjuvant MF59 included in AFLUNOV can induce long-lasting immune-memory and further supports a proactive priming strategy as part of pandemic preparedness efforts" said Dr Joerg Reinhardt, CEO of Novartis Vaccines and Diagnostics, a division of Novartis. "Novartis Vaccines is committed to putting forth the most effective vaccine possible to help protect the global public against a possible pandemic situation." An influenza pandemic occurs when a new influenza strain emerges (one to which humans have no immunity), mutates and spreads globally as a virus. Although it is not possible to predict the actual pandemic influenza strain, global health authorities have identified H5N1 avian influenza as a strain with the greatest pandemic potential in humans[3]. H5N1 is currently circulating in birds and has caused serious illness in more than 380 people worldwide with a mortality rate, among people known to have been infected, of greater than 60%[4].
The purpose of pre-pandemic vaccination is to prime the immune system to better defend against infections from an H5N1 influenza virus and is intended for use before the World Health Organisation (WHO) declares an influenza pandemic. AFLUNOV is the only pre-pandemic vaccine in development with an extensively-studied adjuvant, MF59, that is supported by more than 10 years of clinical safety data and commercial use.
Study details
In an open-label study, 54 healthy adults (age 23-60 years) received two doses of AFLUNOV (7.5microgram MF59-adjuvanted A/Vietnam/1194/2005 clade 1 H5N1) vaccine 21 days apart. Twenty-four subjects were primed with either MF59-adjuvanted or an un-adjuvanted H5N3 (A/duck/Singapore/1997 clade 0-like) vaccine at least 6 years earlier and 30 subjects were unprimed[1]. Some subjects also received a booster dose, 16 months after primary immunisation. Pre and post-vaccination antibody to antigenically diverse H5 viruses were measured by hemagglutination-inhibition (HAI), neutralising antibody (MN) and single radial hemolysis (SRH).
Among primed subjects, protective cross-reacting antibody titers to diverse H5N1 virus variants were seen by day 7 after a single vaccine dose[1]. In subjects primed with an MF59-adjuvanted vaccine responses were statistically significantly higher (P< 0.05) than those primed with un-adjuvanted vaccine. By day 7, after one dose of AFLUNOV, >=80% of MF59-H5 primed recipients achieved sero-protective HAI titers of >=1:40 to all clade 1, 2.1, 2.2, and 2.3 avian H5 virus variants tested as well as the original antigen. In MF59-H5N3 primed subjects, responses were greatest at day 14 with geometric mean antibody titers of 1:378, 1:1754 and 73mm2 to the clade 1 A/Vietnam/2005 vaccine strain and 1:347, 1:2128 and 72mm2 to a clade 2 A/Turkey/2005 variant by HAI, MN and SRH respectively[1].
Novartis Vaccines commitment to pandemic preparedness
The immune-enhancing Novartis Vaccines proprietary adjuvant MF59 may enhance the body's immune response to the vaccine's active constituent (antigen) and offer varying degrees of cross-protection to better defend against the potentially dangerous disease causing infections from an H5N1 virus. In the seasonal influenza vaccine Fluad®, MF59 has been shown to better enhance the antibody response to vaccination when compared to non-adjuvanted vaccines, to increase protection in the elderly, and to provide protection even against influenza strains not included in the vaccine[5], [6]. Fluad has a history of proven safety and tolerability, with more than 40 million doses distributed worldwide since 1997[7].
Novartis Vaccines is working closely with government and regulatory officials worldwide to support pandemic preparedness efforts, including engaging in government contracts to provide H5N1 vaccines for stockpiling. The Co has also been involved in discussions to educate government agencies about the benefits of proactive use of pre-pandemic vaccination in pandemic preparedness planning efforts.
Novartis Vaccines is supportive of the WHO's leadership role in global pandemic planning as discussed in the organisation's "THE WORLD HEALTH REPORT 2007: Global Public Health Security in the 21st Century." The WHO is a key global hub for pandemic preparedness, ensuring cohesion and coordination among all players involved, including the industry, governments of both developed or developing countries and their populations.
The Co also recognises the importance of pandemic influenza preparedness planning within the business community in an effort to protect the global economy. With this commitment, Novartis Vaccines is working with business leaders to support their continuity planning for pandemic preparedness.
About Novartis
Novartis AG provides healthcare solutions that address the evolving needs of patients and societies. Focused solely on healthcare, Novartis offers a diversified portfolio to best meet these needs: innovative medicines, cost-saving generic pharmaceuticals, preventive vaccines, diagnostic tools and consumer health products. Novartis is the only company with leading positions in these areas. In 2007, the Group's continuing operations (excluding divestments in 2007) achieved net sales of US dollars 38.1 billion and net income of US dollars 6.5 billion. Approximately US dollars 6.4 billion was invested in R&D activities throughout the Group. Headquartered in Basel, Switzerland, Novartis Group companies employ approximately 98,000 full-time associates and operate in over 140 countries around the world. For more information, please visit http://www.novartis.com.
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