Aud Katrine Herland Berstad

Design and Recruitment for the GAP Trial, Investigating the Preventive Effect on Asthma Development of an SQ-Standardized Grass Allergy Immunotherapy Tablet in Children with Grass Pollen–Induced Allergic Rhinoconjunctivitis

BACKGROUND Allergic rhinoconjunctivitis is a risk factor for asthma development. Treating the underlying allergy may represent an attractive method of asthma prevention. No regulatory guidance exists in this area, and, to our knowledge, no clinical investigations meeting modern regulatory standards have been published. OBJECTIVE The objective of this publication is to describe the rationale behind the design of and report on the recruitment for the ongoing pediatric Grazax Asthma Prevention (GAP) trial. METHODS The trial was designed for assessment of the preventive effect of an SQ-standardized grass allergy immunotherapy tablet (AIT) on asthma development, both during treatment and after the end of treatment. (The standardized quality [SQ] procedure is a standardization procedure comprising 3 components: total potency, major allergen content, and assessment of extract complexity.) The trial design was discussed with several European Competent Authorities. RESULTS The GAP trial is a multinational, parallel-group, double-blind, placebo-controlled randomized trial. Main eligibility criteria were age of 5 to 12 years, grass pollen-induced allergic rhinoconjunctivitis, no asthma, and no overlapping symptomatic allergies. The children have been randomized 1:1 to receive the grass AIT or placebo once daily for 3 years, followed by a blinded observational period of 2 years. Asthma is assessed by the investigators according to specific diagnostic criteria, used at screening visits before randomization to exclude children with existing asthma, and evaluated at least half-yearly during the trial. Seven months of screening resulted in 812 randomized children at 101 centers in 11 countries. CONCLUSIONS To our knowledge, the GAP trial represents the first double-blind, placebo-controlled randomized trial to assess the preventive effect of allergen-specific immunotherapy on asthma development. A total of 812 children were successfully recruited into the trial. EudraCT number: 2009-011235-12.

A nasal whole-cell pertussis vaccine can induce strong systemic and mucosal antibody responses which are not enhanced by cholera toxin

The immunogenicity of formaldehyde-inactivated Bordetella pertussis (Bp) delivered by the intranasal or colonic-rectal routes in BALB/c mice was studied by immunization four times at weekly intervals with Bp alone, or with Bp mixed with cholera toxin (CT) as a mucosal adjuvant. Mice given Bp subcutaneously, and untreated mice served as controls. Antibody responses in serum, saliva, bronchoalveolar lavage (BAL) fluids and extracts of faeces were measured by enzyme-linked immunosorbent assay. Nasal immunizations with Bp alone induced high levels of IgG antibodies to Bp in serum and BAL fluids, as well as IgA antibodies in serum, saliva, BAL fluids and extracts of faeces. The IgA responses were significantly reduced, and the IgG responses were not increased, when CT was given intranasally together with Bp. However, CT increased the IgA responses to Bp in faeces when both antigens were given rectally, while rectal administration of Bp alone did not induce significant serum or secretory antibody responses. However, when mixed with Bp, the CT itself induced antibodies to CT in serum and samples representing secretions after both nasal and rectal administrations. Thus, Bp is strongly immunogenic when applied intranasally, but not when presented into the intestinal lumen via the rectal route. It appears that CT, which is known to be a mucosal adjuvant and which in itself is a strong mucosal immunogen, will inhibit the immune responses of other strong immunogens when applied on the nasal mucosa.

Inactivated meningococci and pertussis bacteria are immunogenic and act as mucosal adjuvants for a nasal inactivated influenza virus vaccine.

Whole killed meningococci (Nm) and pertussis bacteria (Bp) were tested for mucosal immunogenicity and as mucosal adjuvants for an inactivated influenza virus vaccine given intranasally to unanaesthetized mice. Virus was given alone, or simply mixed with one of the bacterial preparations, in four doses at weekly intervals. The virus alone induced low but significant increases of influenza-specific IgG antibodies in serum measured by ELISA, whereas IgA responses in serum and saliva were insignificant compared to non-immunized controls. With Bp or Nm admixed, serum IgG and IgA and salivary IgA responses to the influenza virus were substantially augmented (P<0.005). However, this adjuvant effect of the bacterial preparations was not significant for responses in the intestine as measured by antibodies in faeces. Antibody responses to Bp itself, but not to Nm, were inhibited by the admixture of the virus vaccine. Moreover, the pertussis preparation induced salivary antibodies which cross-reacted with Nm. Whole-cell bacteria with inherent strong mucosal immunogenicity may also possess mucosal adjuvanticity for admixed particulate antigens which are weakly immunogenic by the nasal route.

Induction of antigen-specific T cell responses in human volunteers after intranasal immunization with a whole-cell pertussis vaccine.

We have studied the ability of an intranasally administered whole-cell pertussis vaccine (WCP) without adjuvant to induce antigen-specific T cell responses in humans. Six adult volunteers were given a vaccine dose (corresponding to 250 microg protein) by nasal spray four times at weekly intervals, and peripheral blood mononuclear cells were assayed for antigen-specific proliferative T cell responses. All six vaccinees had a WCP-specific response, which in four of them remained elevated throughout the 2 month study. All participants also responded to the filamentous haemagglutinin (FHA) antigen, and four of them responded to inactivated pertussis toxin (PTd). A significant correlation between T cell proliferation against WCP and WCP-specific IgA antibody levels in nasal secretions was observed. This demonstrates that intranasal administration of a non-proliferating bacterial vaccine without any additional mucosal adjuvant can induce vaccine-specific T cell responses related to mucosal IgA secretion.

Economic evaluation of second generation pneumococcal conjugate vaccines in Norway

BACKGROUND A seven valent pneumococcal conjugate vaccine (PCV7) was introduced in the Norwegian childhood immunization programme in 2006, and since then the incidence of invasive pneumococcal disease has declined substantially. Recently, two new second generation pneumococcal conjugate vaccines have become available, and an update of the economic evidence is needed. The aim of this study was to estimate incremental costs, health effects and cost-effectiveness of the pneumococcal conjugate vaccines PCV7, PCV13 and PHiD-CV in Norway. METHODS We used a Markov model to estimate costs and epidemiological burden of pneumococcal- and NTHi-related diseases (invasive pneumococcal disease (IPD), Community Acquired Pneumonia (CAP) and acute otitis media (AOM)) for a specific birth cohort. Using the most relevant evidence and assumptions for a Norwegian setting, we calculated incremental costs, health effects and cost-effectiveness for different vaccination strategies. In addition we performed sensitivity analyses for key parameters, tested key assumptions in scenario analyses and explored overall model uncertainty using probabilistic sensitivity analysis. RESULTS The model predicts that both PCV13 and PHiD-CV provide more health gains at a lower cost than PCV7. Differences in health gains between the two second generation vaccines are small for invasive pneumococcal disease but larger for acute otitis media and myringotomy procedures. Consequently, PHiD-CV saves more disease treatment costs and indirect costs than PCV13. CONCLUSION This study predicts that, compared to PVC13, PHiD-CV entails lower costs and greater benefits if the latter is measured in terms of quality adjusted life years. PVC13 entails more life years gained than PHiD-CV, but those come at a cost of NOK 3.1 million (∼€0.4 million) per life year. The results indicate that PHiD-CV is cost-effective compared to PCV13 in the Norwegian setting.

A Non-Living Nasal Influenza Vaccine Can Induce Major Humoral and Cellular Immune Responses in Humans without the Need for Adjuvants

Twenty-eight healthy adult volunteers were immunized intranasally with an inactivated whole-virus influenza vaccine based on the strain A/New Caledonia/20/99 (H1N1), either in saline or mixed with formaldehyde-inactivated Bordetella pertussis as a mucosal adjuvant, or in a thixotropic vehicle with mucoadhesive properties. After four doses, all groups of vaccinees developed significant IgG- and IgA-antibody responses, measured by ELISA, in respectively serum and nasal secretions. None of the volunteers had demonstrable hemagglutination inhibition (HAI) antibodies in serum before being immunized, whereas more than 80% of them reached HAI titers ? 40, considered protective, after immunizations. In addition, cellular immune responses, measured as significant increases in CD4+ T-cell proliferation and granzyme B-producing cytotoxic T-cells, were detected against the vaccine strain as well as against heterologous virus strains (H3N2). However, no additive effect on these responses could be demonstrated with use of B. pertussis or the thixotropic substance in the present vaccines. It appeared, actually, that the mucoadhesive vehicle containing the thixotropic substance was less efficient than were the two other formulations. An influenza vaccine made as a simple particulate formulation of inactivated virus, and given repeatedly onto the nasal mucosa, may thus be an attractive alternative to currently available vaccines.

Influence of Intravenous Anesthesia on Mucosal and Systemic Antibody Responses to Nasal Vaccines

ABSTRACT Inhalation of antigens may stimulate the immune system by way of the upper as well as the lower airways. We have shown that at least 1,000 times more live pneumococci were recovered from pulmonary tissue after being presented as drops of a liquid suspension onto the nares of anesthetized mice compared to the number of bacteria recovered from animals that were not anesthetized in the course of the challenge. Mice that were similarly immunized intranasally by inhalation of three different nonreplicating particulate vaccine formulations, i.e., a meningococcal outer membrane vesicle (OMV) vaccine, a formalin-inactivated whole-virus influenza (INV) vaccine, and the INV vaccine with OMVs as a mucosal adjuvant, during general intravenous anesthesia developed concentrations of vaccine-specific serum immunoglobulin G (IgG) antibodies that were four to nine times higher than in mice that were fully awake during immunizations. The concentrations of IgA antibodies in serum were also higher in anesthetized than in nonanesthetized mice and correlated positively with the corresponding levels of serum IgG antibodies in the anesthetized but not in the nonanesthetized mice. In saliva and feces, however, the concentrations of IgA antibodies were equally high whether or not the animals were dormant during immunizations. The results indicate that intrapulmonary antigen presentation, as a part of an intranasal immunization strategy, is of importance for systemic but not for mucosal antibody responses. A major portion of IgA antibodies in serum may thus be derived from nonmucosal sites.

Bacteria-derived particles as adjuvants for non-replicating nasal vaccines

In attempts to mimic natural infections, vaccines consisting of microbial particles may be delivered directly to mucosal surfaces. In this way, the mucosal as well as the systemic immune systems can be activated. Even non-living particles of bacterial origin have been shown to elicit strong immune responses when administered intranasally. However, some particles such as formalin-inactivated influenza virus may need a mucosal adjuvant to be effective. The bacteria-derived particles seem to possess such an adjuvant activity when mixed with and given intranasally with the less immunogenic killed virus. Possibly, the bacterial particles facilitate uptake of the virus through the mucosal membranes, although an additional influence on the immune response to the virus might be mediated in the lymphoid tissue below the mucosal surface. Bacteria-derived particles in nasal vaccines may thus serve as an alternative adjuvant to derivatives of cholera toxin or the heat-labile toxin from E. coli.

Clinical characteristics of patients with drug hypersensitivity in Norway: a single‐centre study

Drug hypersensitivity reactions (DHRs) represent an important public health problem. Knowledge of their clinical characteristics will provide improved diagnostic approaches to this topic.

Bordetella pertussis can act as adjuvant as well as inhibitor of immune responses to non-replicating nasal vaccines.

In mice immunised intranasally with an inactivated whole-virus influenza (INV) vaccine, or ovalbumin (OVA), formalin-inactivated Bordetella pertussis (Bp) augmented antibody responses to the same degree as did cholera toxin (CT) when simply being mixed with INV or OVA. In order to study possible non-carrier effects of mucosal adjuvants, mice were given Bp or CT intranasally 1 day before or 1 day after the INV vaccines. At high antigen doses, both Bp and CT had an adjuvant effect on antibodies in serum also when given 1 day after the vaccine. However, Bp and CT inhibited such antibody responses in serum and saliva when given 1 day ahead of the vaccine. This inhibitory effect was most marked at low antigen doses, i.e. when the adjuvant effect was less obvious. In that event, Bp also inhibited responses in serum and saliva when given 1 day after the INV vaccine. The inhibition of these responses may thus depend on Bp and CT themselves being strongly immunogenic, and competing with INV for the functional capacity of the mucosal immune system.