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MALMO, SWEDEN – in an interim analysis of an ongoing phase 2 study, Taisei Masuda, MD, reported at the annual meeting of the European Society for Paediatric Infectious Diseases.
The randomized, double-blind, multinational trial remains blinded because follow-up is continuing, so – to the disappointment of the ESPID audience – there are as yet no data on duration of antibody persistence or clinical efficacy.
However, an earlier phase 2 study in 420 healthy participants aged 18-64 years showed that the Takeda vaccine elicited persistent immune responses 1 year post vaccination and that higher antibody levels correlated with a reduced frequency of moderate to severe vomiting and diarrheal illness following oral challenge with norovirus (Clin Vaccine Immunol. 2015 Aug;22[8]:923-9). Follow-up will continue in order to learn how long the protective immune response lasts in adults, according to Dr. Masuda, of Takeda Pharmaceuticals in Zurich.
The bivalent Takeda vaccine is the first candidate vaccine to reach the randomized trial stage. An oral vaccine in tablet form under development by Vaxart, a San Francisco Bay Area biotech company, recently completed preliminary phase 1 studies.
Dr. Masuda explained that the Takeda vaccine contains virus-like particle antigens from norovirus strains GI.1 and GII.4c, which together account for the majority of human norovirus illness. These virus-like particles are formed on the outer surface of the virus. Of note, virus-like particle–based vaccines against hepatitis B and human papillomavirus have won regulatory approval in the United States, Europe, and elsewhere.
He presented data on 120 healthy subjects aged 1 year to less than 4 years old and another 120 aged 4 years to less than 9 years. They are part of a larger phase 2 study of 840 children as young as age 6 weeks. This was a dose-finding study, so participants received various doses of the vaccine on day 1 and either a second dose or a saline injection 28 days later. The vaccine, which contains aluminum hydroxide to enhance immunogenicity, comes in prefilled syringes.
At 57 days of follow-up in this interim analysis, protective seroresponse rates as defined by at least a fourfold increase in histo-blood group antigen–blocking titers approached 100%. In the older group, this was typically achieved with a single dose of vaccine. However, the younger group of children generally derived further benefit from a second dose, according to Dr. Masuda.
In terms of safety concerns, he said no serious adverse events occurred in the study and no one withdrew from the trial because of vaccine-related side effects. The overall safety picture was the same in the two age groups. The incidence of fever of 38° C or higher was similar after administration of vaccine and placebo. Injection site pain occurred in one-quarter of younger vaccine recipients, in 38%-63% of those aged 4 years or older, and in 17%-22% who got placebo injections. Those and other local and systemic adverse events were mostly mild and transient. Their incidence and severity weren’t related to vaccine dosage.
In sum, Dr. Masuda deemed the safety profile “clinically acceptable.”
Session chair Karina Butler, MD, of Temple Street Children’s University Hospital, Dublin, raised the question of how might this vaccine, which may require two doses in younger children, fit into an already crowded pediatric immunization schedule – will parents and physicians embrace it?
Dr. Masuda replied that noroviruses are the No. 1 cause of acute gastroenteritis worldwide and there is a clamor for development of effective vaccines to protect the groups that bear the greatest burden of disease, including children, the elderly, military personnel, cruise ship vacationers, and others who experience crowded conditions. He expressed confidence that a safe and effective vaccine will be in high demand.
“In the future, we’ll look at the possibility of a combination vaccine,” he added.
In response to audience questions, Dr. Masuda said that in adult studies higher levels of immunogenicity have been achieved after vaccination, compared with natural infection; however, there are as yet no pediatric data on that score. Also, investigators have seen evidence of cross-reactivity to the vaccine in some but not all naturally circulating nonvaccine strains.
The vaccine formulation being carried forward into advanced clinical trials in adults is 15 mcg of GI.1/50 mcg of GII.4c (J Infect Dis. 2018 Jan 30;217[4]:597-607).
The phase 2 study presented by Dr. Masuda was supported by the U.S. Army.
MALMO, SWEDEN – in an interim analysis of an ongoing phase 2 study, Taisei Masuda, MD, reported at the annual meeting of the European Society for Paediatric Infectious Diseases.
The randomized, double-blind, multinational trial remains blinded because follow-up is continuing, so – to the disappointment of the ESPID audience – there are as yet no data on duration of antibody persistence or clinical efficacy.
However, an earlier phase 2 study in 420 healthy participants aged 18-64 years showed that the Takeda vaccine elicited persistent immune responses 1 year post vaccination and that higher antibody levels correlated with a reduced frequency of moderate to severe vomiting and diarrheal illness following oral challenge with norovirus (Clin Vaccine Immunol. 2015 Aug;22[8]:923-9). Follow-up will continue in order to learn how long the protective immune response lasts in adults, according to Dr. Masuda, of Takeda Pharmaceuticals in Zurich.
The bivalent Takeda vaccine is the first candidate vaccine to reach the randomized trial stage. An oral vaccine in tablet form under development by Vaxart, a San Francisco Bay Area biotech company, recently completed preliminary phase 1 studies.
Dr. Masuda explained that the Takeda vaccine contains virus-like particle antigens from norovirus strains GI.1 and GII.4c, which together account for the majority of human norovirus illness. These virus-like particles are formed on the outer surface of the virus. Of note, virus-like particle–based vaccines against hepatitis B and human papillomavirus have won regulatory approval in the United States, Europe, and elsewhere.
He presented data on 120 healthy subjects aged 1 year to less than 4 years old and another 120 aged 4 years to less than 9 years. They are part of a larger phase 2 study of 840 children as young as age 6 weeks. This was a dose-finding study, so participants received various doses of the vaccine on day 1 and either a second dose or a saline injection 28 days later. The vaccine, which contains aluminum hydroxide to enhance immunogenicity, comes in prefilled syringes.
At 57 days of follow-up in this interim analysis, protective seroresponse rates as defined by at least a fourfold increase in histo-blood group antigen–blocking titers approached 100%. In the older group, this was typically achieved with a single dose of vaccine. However, the younger group of children generally derived further benefit from a second dose, according to Dr. Masuda.
In terms of safety concerns, he said no serious adverse events occurred in the study and no one withdrew from the trial because of vaccine-related side effects. The overall safety picture was the same in the two age groups. The incidence of fever of 38° C or higher was similar after administration of vaccine and placebo. Injection site pain occurred in one-quarter of younger vaccine recipients, in 38%-63% of those aged 4 years or older, and in 17%-22% who got placebo injections. Those and other local and systemic adverse events were mostly mild and transient. Their incidence and severity weren’t related to vaccine dosage.
In sum, Dr. Masuda deemed the safety profile “clinically acceptable.”
Session chair Karina Butler, MD, of Temple Street Children’s University Hospital, Dublin, raised the question of how might this vaccine, which may require two doses in younger children, fit into an already crowded pediatric immunization schedule – will parents and physicians embrace it?
Dr. Masuda replied that noroviruses are the No. 1 cause of acute gastroenteritis worldwide and there is a clamor for development of effective vaccines to protect the groups that bear the greatest burden of disease, including children, the elderly, military personnel, cruise ship vacationers, and others who experience crowded conditions. He expressed confidence that a safe and effective vaccine will be in high demand.
“In the future, we’ll look at the possibility of a combination vaccine,” he added.
In response to audience questions, Dr. Masuda said that in adult studies higher levels of immunogenicity have been achieved after vaccination, compared with natural infection; however, there are as yet no pediatric data on that score. Also, investigators have seen evidence of cross-reactivity to the vaccine in some but not all naturally circulating nonvaccine strains.
The vaccine formulation being carried forward into advanced clinical trials in adults is 15 mcg of GI.1/50 mcg of GII.4c (J Infect Dis. 2018 Jan 30;217[4]:597-607).
The phase 2 study presented by Dr. Masuda was supported by the U.S. Army.
MALMO, SWEDEN – in an interim analysis of an ongoing phase 2 study, Taisei Masuda, MD, reported at the annual meeting of the European Society for Paediatric Infectious Diseases.
The randomized, double-blind, multinational trial remains blinded because follow-up is continuing, so – to the disappointment of the ESPID audience – there are as yet no data on duration of antibody persistence or clinical efficacy.
However, an earlier phase 2 study in 420 healthy participants aged 18-64 years showed that the Takeda vaccine elicited persistent immune responses 1 year post vaccination and that higher antibody levels correlated with a reduced frequency of moderate to severe vomiting and diarrheal illness following oral challenge with norovirus (Clin Vaccine Immunol. 2015 Aug;22[8]:923-9). Follow-up will continue in order to learn how long the protective immune response lasts in adults, according to Dr. Masuda, of Takeda Pharmaceuticals in Zurich.
The bivalent Takeda vaccine is the first candidate vaccine to reach the randomized trial stage. An oral vaccine in tablet form under development by Vaxart, a San Francisco Bay Area biotech company, recently completed preliminary phase 1 studies.
Dr. Masuda explained that the Takeda vaccine contains virus-like particle antigens from norovirus strains GI.1 and GII.4c, which together account for the majority of human norovirus illness. These virus-like particles are formed on the outer surface of the virus. Of note, virus-like particle–based vaccines against hepatitis B and human papillomavirus have won regulatory approval in the United States, Europe, and elsewhere.
He presented data on 120 healthy subjects aged 1 year to less than 4 years old and another 120 aged 4 years to less than 9 years. They are part of a larger phase 2 study of 840 children as young as age 6 weeks. This was a dose-finding study, so participants received various doses of the vaccine on day 1 and either a second dose or a saline injection 28 days later. The vaccine, which contains aluminum hydroxide to enhance immunogenicity, comes in prefilled syringes.
At 57 days of follow-up in this interim analysis, protective seroresponse rates as defined by at least a fourfold increase in histo-blood group antigen–blocking titers approached 100%. In the older group, this was typically achieved with a single dose of vaccine. However, the younger group of children generally derived further benefit from a second dose, according to Dr. Masuda.
In terms of safety concerns, he said no serious adverse events occurred in the study and no one withdrew from the trial because of vaccine-related side effects. The overall safety picture was the same in the two age groups. The incidence of fever of 38° C or higher was similar after administration of vaccine and placebo. Injection site pain occurred in one-quarter of younger vaccine recipients, in 38%-63% of those aged 4 years or older, and in 17%-22% who got placebo injections. Those and other local and systemic adverse events were mostly mild and transient. Their incidence and severity weren’t related to vaccine dosage.
In sum, Dr. Masuda deemed the safety profile “clinically acceptable.”
Session chair Karina Butler, MD, of Temple Street Children’s University Hospital, Dublin, raised the question of how might this vaccine, which may require two doses in younger children, fit into an already crowded pediatric immunization schedule – will parents and physicians embrace it?
Dr. Masuda replied that noroviruses are the No. 1 cause of acute gastroenteritis worldwide and there is a clamor for development of effective vaccines to protect the groups that bear the greatest burden of disease, including children, the elderly, military personnel, cruise ship vacationers, and others who experience crowded conditions. He expressed confidence that a safe and effective vaccine will be in high demand.
“In the future, we’ll look at the possibility of a combination vaccine,” he added.
In response to audience questions, Dr. Masuda said that in adult studies higher levels of immunogenicity have been achieved after vaccination, compared with natural infection; however, there are as yet no pediatric data on that score. Also, investigators have seen evidence of cross-reactivity to the vaccine in some but not all naturally circulating nonvaccine strains.
The vaccine formulation being carried forward into advanced clinical trials in adults is 15 mcg of GI.1/50 mcg of GII.4c (J Infect Dis. 2018 Jan 30;217[4]:597-607).
The phase 2 study presented by Dr. Masuda was supported by the U.S. Army.
REPORTING FROM ESPID 2018
Key clinical point: Hope runs high that an effective norovirus vaccine is in the works.
Major finding: Protective seroresponse rates against the two chief disease-causing strains of norovirus were seen in nearly 100% of vaccinated children aged 1-8 years.
Study details: This is an ongoing prospective, multicenter, double-blind, phase 2 randomized trial including 840 children.
Disclosures: The study was supported by the U.S. Army and presented by an employee of Takeda Pharmaceuticals.