Type III hypersensitivity reactions to a B cell epitope antigen are abrogated using a depot forming vaccine platform.

Peptide antigens are combined with an adjuvant in order to increase immunogenicity in vivo. The immunogenicity and safety of a RSV vaccine formulated in a novel oil-based platform, DepoVax™ (DPX), was compared to an alum formulation. A peptide B cell epitope derived from RSV small hydrophobic ectodomain (SHe) served as the antigen. Both vaccines induced SHe-specific antibodies after immunization of mice. A single dose of the DPX-based formulation resulted in anti-SHe titres for up to 20 weeks. Boosting with Alum-SHe, but not with DPX-SHe, led to unexpected clinical signs such as decreased activity, cyanosis and drop in body temperature in mice but not in rabbits. The severity of adverse reactions correlated with magnitude of SHe-specific IgG immune responses and decreased complement component 3 plasma levels, indicating a type III hypersensitivity reaction. By RP-HPLC analysis, we found that only 8-20% of the antigen was found to be adsorbed to alum in vitro, indicating that this antigen is likely released systemically upon injection in vivo. Clinical signs were not observed in rabbits, indicating the response correlates with peptide dose relative to size of animal. These results suggest that peptide antigens targeted to produce B cell mediated response may result in increased incidence of type III hypersensitivity reactions when delivered in non-depot forming vaccines. The DPX formulation induced strong antibody titres to the antigen without causing adverse events, likely due to the strength of the depot in vivo, and demonstrates the potential safety and immunogenicity of this platform for B cell peptide antigens.

Immunogenicity of heterologous H5N1 influenza booster vaccination 6 or 18 months after primary vaccination in adults: a randomized controlled clinical trial.

BACKGROUND: Highly pathogenic avian influenza A/H5N1 viruses continue to circulate in birds and infect humans causing serious illness and death. METHODS: In this randomized, observer-blinded study, adults ≥18 years of age (n=841) received 3.75 or 7.5 µg hemagglutinin antigen (HA) of an AS03-adjuvanted (AS03A or AS03B) A/Indonesia/5/2005 H5N1 (subclade 2.1) vaccine (priming), followed by the same HA dose of AS03-adjuvanted A/turkey/Turkey/1/05 H5N1 (clade 2.2) influenza vaccine as a booster 6 or 18 months after priming; an unprimed group received placebo at Day 0, and 3.75 µg HA of AS03A-adjuvanted booster vaccine at 6 and 18 months. Antibody responses were assessed by hemagglutination-inhibition assay (HI). Microneutralization (MN) antibody and cellular immunoassays were assessed in a subset of participants. RESULTS: Geometric mean titers (GMTs) and seroconversion rates (SCRs) were higher in primed vs. unprimed subjects against the booster strain 10 days following booster vaccination at month 6 and month 18. After the booster at 18 months, the lower limit of the 97.5% confidence interval for the difference in SCR and GMT ratios between primed and unprimed subjects was >15% and >2.0, respectively, fulfilling the primary endpoint criteria for superiority against the booster strain. MN and cellular immune responses corresponded with the immunogenicity seen in HI measures. CONCLUSIONS: Adults primed with a dose-sparing oil-in-water adjuvanted H5N1 subclade vaccine had rapid and durable antibody responses to a heterologous subclade boosting vaccine given 6 or 18 months later.

A randomized, controlled non-inferiority trial comparing A(H1N1)pmd09 vaccine antigen, with and without AS03 adjuvant system, co-administered or sequentially administered with an inactivated trivalent seasonal influenza vaccine.

BACKGROUND: At the time of the influenza A(H1N1)pmd09 pandemic it was not known if concurrent or sequential administration of seasonal trivalent influenza vaccine (TIV) with pandemic vaccine was preferred. METHODS: Immunogenicity and safety were assessed in 871 healthy subjects aged 19-40 years who were randomised into six groups to receive co-administration or sequential administration of TIV and two doses of A(H1N1)pmd09 vaccine (either unadjuvanted or adjuvanted with AS03, an α-tocopherol and squalene-based oil-in-water emulsion). RESULTS: Safety and immunogenicity data (by haemagglutination inhibition [HI] assay) after each dose and six months post-Dose 1 are reported here. Co-administration of A(H1N1)pmd09 vaccine with TIV reduced the HI immune responses to A(H1N1)pmd09 vaccine. However, serologic responses with both co-administration and sequential schedules met the European and US regulatory criteria for pandemic and seasonal influenza vaccines up to six months following the first vaccine dose. The AS03-adjuvanted formulation elicited higher immune responses at all time points. Prior administration or co-administration of A(H1N1)pmd09 vaccine did not affect immune responses to TIV. CONCLUSIONS: Co-administration of TIV and A(H1N1)pmd09 vaccine negatively influenced A(H1N1)pmd09 vaccine immunogenicity but had no effect on TIV responses. The non-adjuvanted and adjuvanted vaccines demonstrated strong immune responses against all vaccine strains for up to six months following the first vaccine dose.

Randomized, multicenter trial of a single dose of AS03-adjuvanted or unadjuvanted H1N1 2009 pandemic influenza vaccine in children 6 months to <9 years of age: safety and immunogenicity.

BACKGROUND: During the 2009-2010 influenza pandemic, we evaluated the immunogenicity and safety of different H1N1 2009 pandemic influenza vaccines delivering various viral hemagglutinin (HA) doses with or without AS03 (a tocopherol oil-in-water emulsion-based adjuvant system) in children (NCT00976820). METHODS: Three hundred twenty-two healthy children 6 months to <9 years of age were randomized to receive 2 doses of nonadjuvanted (15 µg or 7.5 µg HA) or adjuvanted vaccine (3.75 µg HA/AS03A or 1.9 µg HA/AS03B), 21 days apart. Blood samples before and after each dose were tested for immune responses using hemagglutination inhibition and microneutralization assays. Safety assessments were done up to day 385. RESULTS: The first dose of both AS03-adjuvanted vaccines elicited strong immune responses (seroprotection rates: 98.3%/99.0%; seroconversion rates: 94.9%/97.0%; geometric mean fold rises: 36.2/33.6), which were higher post-dose 2 (seroprotection rate: 100.0%/100%; seroconversion rate: 100.0%/98.8%; geometric mean fold rise: 157.1/151.6), meeting European regulatory criteria on days 21 and 42. The nonadjuvanted 15 µg HA vaccine also met the regulatory criteria after each dose; the 7.5 µg HA vaccine met them only post-dose 2. Six months post-dose 1, all vaccines except the nonadjuvanted 7.5 µg HA vaccine met European regulatory criteria. Neutralizing antibody response paralleled the hemagglutination inhibition immune response after each dose. Pain at the injection site, lasting 2-3 days, was more common following adjuvanted than nonadjuvanted vaccination. CONCLUSIONS: AS03-adjuvanted H1N1 2009 pandemic influenza vaccine (3.75 µg or 1.9 µg HA), administered as 2 doses, was highly immunogenic, induced long-term immune response to 6 months, with a clinically acceptable safety profile in children aged 6 months to <9 years of age.

Safety and immunogenicity of 2010-2011 H1N12009-containing trivalent inactivated influenza vaccine in children 12-59 months of age previously given AS03-adjuvanted H1N12009 pandemic vaccine: a PHAC/CIHR Influenza Research Network (PCIRN) study.

BACKGROUND: Concern arose in 2010 that reactogenicity, particularly febrile seizures, to influenza A/H1N1-containing 2010-2011 trivalent seasonal inactivated influenza vaccine (TIV) could occur in young children who had been previously immunized and/or infected with the pandemic strain. We conducted a pre-season study of 2010-2011 TIV safety and immunogenicity in children 12-59 months of age to inform public health decision making. METHODS: Children immunized with 1 or 2 doses of the pandemic vaccine, with or without the 2009-10 TIV, received 1 or 2 doses of 2010-11 TIV in an observational, multicentre Canadian study. Standard safety monitoring was enhanced by a telephone call at ~24 h post-TIV when adverse events were expected to peak. Summary safety reports were rapidly reported to public health before the launch of public programs. TIV immunogenicity was assessed day 0, and 21 days after final vaccination. Clinical Trials Registration NCT01180621. RESULTS: Among 207 children, a general adverse event was reported by 60.9% of children post-dose one and by 58.3% post-dose two. Only severe fever (>38.5°C) was more common in two-dose compared to one dose recipients (16.7%, n=4 v. 1.0%, n=2). At baseline 99.0% of participants had A/H1N1 hemagglutinin inhibition (HAI) titers ≥10, and 85.5% had a protective titer of ≥40 (95% CI 80.0, 90.0). Baseline geometric mean titers (GMT) were higher in recipients of a 2-dose schedule of pandemic vaccine compared to one-dose recipients: 153.1 (95% CI 126.2, 185.7) v. 78.8 ((58.1, 106.8, p<0.001). At 21 days, all regulatory criteria for influenza vaccine immunogenicity were exceeded for A/H1N1 and H3N2, but responses to the B antigen were poor. No correlations between reactogenicity and either baseline high influenza titers or serologic response to revaccination were evident. CONCLUSIONS: Infants and toddlers who received AS03-adjuvanted A/H1N1 2009 vaccine up to 11 months earlier retained high titers in the subsequent season but re-exposure to A/H1N1 2009 antigen in TIV resulted in no unusual adverse effects and 100% were sero-protected for A/H1N1 after receipt of the 2010-11 TIV.

Immunological priming induced by a two-dose series of H5N1 influenza antigen, administered alone or in combination with two different formulations of AS03 adjuvant in adults: results of a randomised single heterologous booster dose study at 15 months.

One influenza pandemic preparedness strategy involves priming a population with a pre-pandemic subtype-specific vaccine and boosting the immunological response at the time of the pandemic with a strain-matched vaccine. In the current study, adults (n=469) randomised 15 months previously to receive an A/Indonesia/5/2005 (H5N1) influenza vaccine (3.75 µg haemagglutinin antigen [HA]) administered alone or in combination with an oil-in-water emulsion based Adjuvant System containing 11.86 mg (AS03(A)) or 5.93 mg (AS03(B)) tocopherol per dose, received one booster dose of A/turkey/Turkey/1/2005 (H5N1) vaccine (3.75 µg HA) with or without AS03(A). An anamnestic antibody response that met US regulatory acceptance criteria was observed 15 months after priming. Although superior immunogenicity of AS03-adjuvanted compared to unadjuvanted priming was not demonstrated, higher antibody titres which persisted longer were seen when both priming and boosting regimens were adjuvanted. This may affect duration of response or heterologous immunity. The booster vaccines had a clinically acceptable safety/reactogenicity profile after adjuvanted or unadjuvanted priming. This study has been registered at www.clinicaltrials.gov NCT00771615.

Safety and cross-reactive immunogenicity of candidate AS03-adjuvanted prepandemic H5N1 influenza vaccines: a randomized controlled phase 1/2 trial in adults.

BACKGROUND: The tocopherol-based oil-in-water emulsion adjuvant system family (AS03) improves antigen sparing with split-virion H5N1 influenza vaccines, representing an important development for pandemic preparedness. In this phase 1/2 randomized, controlled, observer-blinded study in 680 adults, we assessed the immunogenicity and safety of A/Indonesia/5/05 H5N1 (IBCDC-RG2, clade 2.1) prepandemic candidate vaccines produced at 2 separate manufacturing sites. METHODS: Two doses, each of which contained 3.75 microg of hemagglutinin antigen, were given 21 days apart either without adjuvant or with an adjuvant system containing 11.86 mg or 5.93 mg of tocopherol (AS03). RESULTS: The AS03-adjuvanted A/Indonesia/05/2005 (NIBRG-14) vaccines were significantly more immunogenic than nonadjuvanted vaccine in homologous assays. Neutralizing cross-clade immunogenicity against clades 1, 2.2, and 2.3 was demonstrated at day 42 with all vaccines; at 6 months, seroconversion rates were highest for clade 2.2 (60.7%) and for clade 1 (38.3%). Adjuvantation was associated with increased short-term injection-site reactions (pain) in 80% of participants, with such reactions assessed as being of grade 3 severity for 4.0% of doses. No other safety or reactogenicity concerns were identified over 6 months of follow-up. CONCLUSIONS: Humoral responses against the adjuvanted 3.75-microg hemagglutinin antigen vaccines from both manufacturing sites fulfilled European and US licensure criteria for immunogenicity for influenza vaccines.

A dose-ranging study of a subunit Respiratory Syncytial Virus subtype A vaccine with and without aluminum phosphate adjuvantation in adults > or =65 years of age.

We studied the safety and immunogenicity of a Respiratory Syncytial Virus (RSV)-A vaccine containing subunit antigens F, G and M in older persons, and its effect on influenza vaccine immunogenicity. In a dose-ranging, placebo-controlled, blinded trial 561 adults > or =65 years of age at five Canadian sites were randomized to one intramuscular injection of either 100, 50 or 25 microg RSV-A-alum vaccine or 100 microg non-adjuvanted RSV-A vaccine, or alum-placebo. All participants were offered inactivated influenza vaccine on day 32. Immunization was well tolerated and reactogenicity was similar between the RSV and influenza vaccines and the alum-placebo. Only the 100 microg non-adjuvanted RSV vaccine achieved the primary immunogenicity outcome of eliciting a > or =4-fold rise in neutralizing antibody (NA) titres against RSV-A in > or =50% of participants at day 32. Geometric mean titres against RSV-A and -B at all points were comparable in 100 microg adjuvanted and non-adjuvanted groups. At day 32, a > or =4-fold haemagluttinin inhibition (HI) antibody response or HI > or =40 to Influenza (A-H3N2) was seen in >74% of participants; no difference was seen between groups. A subunit non-alum-containing RSV-A vaccine was well tolerated in a large population > or =65 years and did not interfere with influenza vaccine immunogenicity. This RSV-A-based vaccine demonstrated NA rise which could provide seasonal protection against severe RSV illnesses from RSV-A or -B and warrants further testing to determine its efficacy in the prevention of clinical illness in elderly persons.

Immunogenicity of a tetravalent meningococcal glycoconjugate vaccine in infants: a randomized controlled trial.

CONTEXT: Immunization with a meningococcal tetravalent (serogroup ACWY) glycoconjugate vaccine is recommended for all US adolescents. However, the currently licensed vaccine is poorly immunogenic in infancy, when the highest rates of disease are observed. OBJECTIVE: To determine the immunogenicity of a novel tetravalent CRM(197)-conjugated meningococcal vaccine (MenACWY) in infants. DESIGN, SETTING, AND PARTICIPANTS: Randomized, open-label, controlled study of 225 UK and 196 Canadian 2-month-olds from August 2004 to September 2006. INTERVENTION: UK infants received a primary course of MenACWY (at 2, 3, and 4 months or 2 and 4 months) or Neisseria meningitidis serogroup C monovalent meningococcal glycoconjugate vaccine (MenC) (at 2 and 4 months). All received MenACWY at 12 months. Canadian infants received MenACWY at 2, 4, and 6 months or 2 and 4 months; at 12 months they received MenACWY, a plain tetravalent polysaccharide vaccine, or no vaccine. MAIN OUTCOME MEASURE: Percentage of infants with a human complement serum bactericidal activity (hSBA) titer >or=1:4 after a primary course of MenACWY and after a 12-month booster. Safety and reactogenicity of MenACWY were also assessed. RESULTS: According to the prespecified per-protocol analysis, the percentages (95% CIs) of MenACWY 2-, 3-, and 4-month recipients with hSBA titers >or=1:4 after primary immunization were serogroup A, 93% (84%-98%); C, 96% (89%-99%); W-135, 97% (90%-100%); and Y, 94% (86%-98%). With a post hoc intention-to-treat analysis with imputed values for missing data, these values were unchanged for serogroups C and Y; for serogroup A, values were 92% (84%-97%), and for W-135, 97% (91%-99%). For the per-protocol analysis of MenACWY 2-, 4-, and 6-month recipients, the percentages (95% CIs) of responders were A, 81% (71%-89%); C, 98% (92%-100%); W-135, 99% (93%-100%); and Y, 98% (92%-100%). With the imputed value analysis, these values were A, 83% (74%-89%); C, 98% (93%-99%); W-135, 99% (94%-100%); and Y, 98% (92%-99%). At least 84% of MenACWY 2- and 4-month recipients achieved hSBA titers >or=1:4 for serogroups C, W-135, and Y after primary immunization, as did at least 60% for serogroup A (per-protocol and imputation analysis). At least 95% of primary and booster MenACWY recipients achieved hSBA titers >or=1:4 for serogroups C, W-135, and Y at 13 months, as did at least 84% for serogroup A (per-protocol and imputation analysis). During the primary immunization course, postimmunization pain on leg movement was observed in 2% of UK MenACWY 2- and 4-month recipients and 4% of MenC 2- and 4-month recipients; a temperature of 38 degrees C or greater was observed in 4% and 2% in these groups, respectively. CONCLUSION: MenACWY is well tolerated and immunogenic in infancy. Trial Registration clinicaltrials.gov Identifier: NCT00262002.