[Show abstract][Hide abstract] ABSTRACT: Background:
Respiratory syncytial virus (RSV) is a leading cause of infant morbidity and mortality. A recombinant RSV fusion protein nanoparticle vaccine (RSV F vaccine) candidate for maternal immunization was tested for safety and immunogenicity in women of childbearing age.
Three hundred thirty women (18-35 years) were randomized to receive 1 or 2 doses of RSV F vaccine (60 or 90 µg) with or without aluminum phosphate adjuvant, or placebo at days 0 and 28. Safety was evaluated over 180 days; immunogenicity and RSV infection rates were evaluated over 112 days.
All vaccine formulations were well tolerated, without vaccine-related serious adverse events. Anti-F immunoglobulin G antibodies rose 6.5-15.6-fold, with significantly higher levels in 2-dose, adjuvanted regimens at day 56. Palivizumab-competitive antibody levels were undetectable at day 0 but increased up to 325 µg/mL at day 56. A 2.7- and 3.5-fold rise in RSV/A and RSV/B microneutralization antibodies were noted at day 56. Between days 56 and 112, 21% (12/56) of placebo recipients and 11% of vaccinees (26/244) showed evidence of a recent RSV infection (P = .04).
The vaccine appeared safe, immunogenic, and reduced RSV infections. Further development as a vaccine for use in maternal immunization is warranted.
Clinical trials registration:
No preview · Article · Aug 2015 · The Journal of Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: Post-infectious immunity to respiratory syncytial virus (RSV) infection results in limited protection as evidenced by the high rate of infant hospitalization in the face of high titer, maternally derived RSV-specific antibodies. By contrast, RSV fusion (F) glycoprotein antigenic site II humanized monoclonal antibodies, palivizumab and motavizumab, have been shown to reduce RSV-related hospitalization in infants. Immunogenicity and efficacy studies were conducted in cotton rats comparing a recombinant RSV F nanoparticle vaccine with palivizumab and controlled with live RSV virus intranasal immunization and, formalin inactivated RSV vaccine. Active immunization with RSV F nanoparticle vaccine containing an alum adjuvant induced serum levels of palivizumab competing antibody (PCA) greater than passive administration of 15 mg/kg palivizumab (human prophylactic dose) in cotton rats and neutralized RSV-A and RSV-B viruses. Immunization prevented detectable RSV replication in the lungs and, unlike passive administration of palivizumab, in the nasal passage of challenged cotton rats. Histology of lung tissues following RSV challenge showed no enhanced disease in the vaccinated groups in contrast to formalin inactivated ‘Lot 100’ vaccine. Passive intramuscular administration of RSV F vaccine-induced immune sera one day prior to challenge of cotton rats reduced viral titers by 2 or more log10 virus per gram of lung and nasal tissue and at doses less than palivizumab. A recombinant RSV F nanoparticle vaccine protected lower and upper respiratory tract against both RSV A and B strain infection and induced polyclonal palivizumab competing antibodies similar to but potentially more broadly protective against RSV than palivizumab.
[Show abstract][Hide abstract] ABSTRACT: Enterotoxigenic Escherichia coli (ETEC) is a major cause of travellers' diarrhoea. We investigated the efficacy and safety of a skin-patch vaccine containing the pathogen's heat-labile toxin (LT) in a population of travellers to Mexico and Guatemala.
In this phase 3, randomised, double-blind, placebo-controlled field trial, healthy adults (aged 18-64 years) travelling from Germany or the UK to Mexico or Guatemala were assigned in a 1:1 ratio by a dynamic electronic randomisation system to receive transcutaneous immunisation with a patch containing 37·5 μg of ETEC LT or a placebo patch. Participants, site staff, and the investigators who did the analyses were masked to group assignment. Participants were vaccinated before travel, with two patches given 14 days apart. In the destination country, participants tracked stool output in a diary and provided stool samples for pathogen identification if diarrhoea occurred. The primary endpoint was the proportion of participants with at least one episode of moderate-to-severe diarrhoea (defined as four or more unformed stools in a 24 h period) in which either or both ETEC enterotoxins (LT and heat-stable toxin [ST]) were detected. The study is registered at ClinicalTrials.gov, number NCT00993681.
2036 participants were recruited and randomly assigned between Oct 14, 2009, and Aug 13, 2010, with 1016 allocated to receive the LT patch and 1020 the placebo patch. 821 participants in the LT-patch group and 823 in the placebo group received both vaccinations and were analysed in the per-protocol population. 30 (3·7%, 95% CI 2·5-5·2) participants in the LT-patch group and 46 (5·6%, 4·1-7·4) in the placebo group had moderate or severe ETEC diarrhoea (vaccine efficacy 34·6%, -2·2 to 58·9; p=0·0621). 9333 local (ie, patch-site) adverse events (including erythema, rash, pruritus, hyperpigmentation, pain, hypopigmentation, and oedema) occurred in 943 (93%) of 1015 participants in the LT-patch group, compared with 1444 local adverse events in 574 (56%) of 1019 participants in the placebo group (p<0·0001). Serious adverse events occurred in 25 participants (14 in the LT-patch group and 11 in the placebo group), with all regarded as either unrelated or possibly related to treatment. Vaccine-induced hyperpigmentation persisted for at least 180 days after vaccination in 150 (18%) of the 849 participants who received both vaccinations and returned for final assessment in the LT-patch group, compared with none of the 842 participants in the placebo group. The vaccine was immunogenic, with a post-vaccination geometric mean titre of LT-specific serum immunoglobulin G of 3400·29, compared with 315·41 in the placebo group.
Although the LT antigen was delivered effectively by the skin patch, the vaccine did not protect travellers against diarrhoea caused by ETEC or other organisms. Future vaccines against travellers' diarrhoea might need to include several antigens against various diarrhoeal pathogens, and might need to be able to generate mucosal and higher systemic immunity.
No preview · Article · Nov 2013 · The Lancet Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: To the Editor: Avian-origin influenza A (H7N9) viruses emerged as human pathogens in China in 2013 and have caused 137 cases and 45 deaths to date.(1) These viruses have acquired mutations that could facilitate infection in mammals,(2) which could pose a pandemic threat if the viruses become readily transmissible in humans. Vaccines are a key defense against pandemics, but candidate vaccines featuring H7 hemagglutinins (HA) have been poorly immunogenic.(3) We have previously described the development, manufacture, and efficacy in mice of an A/Anhui/1/13 (H7N9) viruslike particle (VLP) vaccine produced in insect cells with the use of recombinant baculovirus. This vaccine . . .
No preview · Article · Nov 2013 · New England Journal of Medicine
[Show abstract][Hide abstract] ABSTRACT: The recent emergence of severe human illness caused by avian-origin influenza A(H7N9) viruses in China has precipitated a global effort to rapidly develop and test vaccine candidates. To date, non-A(H7N9) H7 subtype influenza vaccine candidates have been poorly immunogenic and difficulties in production of A(H7N9) virus seed strains have been encountered. A candidate recombinant A(H7N9) vaccine consisting of full length, unmodified hemagglutinin (HA) and neuraminidase (NA) from the A/Anhui/1/2013 and the matrix 1 (M1) protein from the A/Indonesia/05/2005 (H5N1) were cloned into a baculovirus vector. Baculovirus infected Spodoptera frugiperda (Sf9) insect cells secreted virus like particles (VLP) composed of HA, NA, and M1 that resemble mature influenza virions. Genetic construction of vaccine from acquisition of an H7N9 genomic sequence to production of A(H7N9) VLP occurred in 26 days. The immunogenicity and efficacy of A/Anhui/1/2013 (H7N9) VLP vaccine administered on days 0 and 14 were evaluated in a lethal wild-type challenge Balb/c mouse model. Control groups included a non-homologous H7 vaccine (A/chicken/Jalisco/CPA1/2012 (H7N3)-VLP), and A/Indonesia/05/2005 (H5N1)-VLP, or placebo. All vaccines were administered with or without ISCOMATRIX. A(H7N9) VLP elicited hemagglutination-inhibition (HAI) antibody titers of ≥1:64 against the homologous virus, cross-reactive HAI against the heterologous A(H7N3), and 3- to 4-fold higher HAI responses in corresponding ISCOMATRIX subgroups. Similarly, all doses of H7N9 VLP elicited anti-neuraminidase (NA) antibody, with 3- to 4-fold higher responses measured in the corresponding ISCOMATRIX subgroups. The non-homologous H7 vaccine induced both H7N3 and H7N9 HAI but no N9 anti-NA antibodies. A lethal murine wild-type A/Anhui/1/2013 (H7N9) challenge demonstrated 100% survival of all animals receiving A(H7N9) and A(H7N3) vaccine, versus 0% survival in A(H5N1) vaccine and placebo groups. Together, the data demonstrate that recombinant H7N9 vaccine can be rapidly developed that was immunogenic and efficacious supporting testing in man as a pandemic influenza H7N9 vaccine candidate.
[Show abstract][Hide abstract] ABSTRACT: Adults and children today are the benefactors of more than a century of research and development that has resulted in a great variety of licensed vaccines. Vaccine coverage in developed countries is, on the whole, exceptional, and has led to an expectation of a long and healthy life for most children born in this setting. However, it is possible to falsely conclude that the major infectious disease challenges are addressed and few novel vaccine targets remain. There is in fact an endless variety of common pathogens, emerging infections and potential pandemics that will continue to plague humans and drive the need for further discovery, and innovation. The past successes and new challenges will undoubtedly stimulate the vaccinologists of the world to move new ideas down the long and hard slog to testing and approval. These past successes and current challenges, and, the general momentum of vaccine science today, has stimulated an unprecedented level of R&D surrounding novel and existing vaccines. The growth of international markets, more sophisticated and complex regulatory pathways, NGO commitments to the developing world unmet needs have made vaccine licensure ever more a daunting challenge. With this setting in mind, the new book, Development of Novel Vaccines by Gabain and Klade is a welcome resource.
No preview · Article · Apr 2013 · Human Vaccines & Immunotherapeutics
[Show abstract][Hide abstract] ABSTRACT: Respiratory Syncytial Virus (RSV) is an important viral agent causing severe respiratory tract disease in infants and children as well as in the elderly and immunocompromised individuals. The lack of a safe and effective RSV vaccine represents a major unmet medical need. RSV fusion (F) surface glycoprotein was modified and cloned into a baculovirus vector for efficient expression in Sf9 insect cells. Recombinant RSV F was glycosylated and cleaved into covalently linked F2 and F1 polypeptides that formed homotrimers. RSV F extracted and purified from insect cell membranes assembled into 40 nm protein nanoparticles composed of multiple RSV F oligomers arranged in the form of rosettes. The immunogenicity and protective efficacy of purified RSV F nanoparticles was compared to live and formalin inactivated RSV in cotton rats. Immunized animals induced neutralizing serum antibodies, inhibited virus replication in the lungs, and had no signs of disease enhancement in the respiratory track of challenged animals. RSV F nanoparticles also induced IgG competitive for binding of palivizumab neutralizing monoclonal antibody to RSV F antigenic site II. Antibodies to this epitope are known to protect against RSV when passively administered in high risk infants. Together these data provide a rational for continued development a recombinant RSV F nanoparticle vaccine candidate.
[Show abstract][Hide abstract] ABSTRACT: Objective:
We performed a Phase 1 randomized, observer-blinded, placebo-controlled trial to evaluate the safety and immunogenicity of a recombinant respiratory syncytial virus (RSV) fusion (F) protein nanoparticle vaccine.
Six formulations with (5, 15, 30 and 60 μg) and without (30 and 60 μg) aluminum phosphate (AdjuPhos) were administered intramuscularly on day 0 and 30 in a dose escalating fashion to healthy adults 18-49 years of age. Solicited and unsolicited events were collected through day 210. Immunogenicity measures taken at day 0, 30 and 60 included RSV A and B microneutralization, anti-F IgG, antigenic site II peptide and palivizumab competitive antibodies.
The vaccine was well-tolerated, with no evident dose-related toxicity or attributable SAEs. At day 60 both RSV A and B microneutralization was significantly increased in vaccinees versus placebo. Across all vaccinees there was a 7- to 19-fold increase in the anti-F IgG and a 7- to 24-fold increase in the antigenic site II binding and palivizumab competitive antibodies.
The RSV F nanoparticle vaccine candidate was well tolerated without dose-related increases in adverse events. Measures of immunity indicate that neutralization, anti-RSV F IgG titers and palivizumab competing antibodies were induced at levels that have been associated with decreased risk of hospitalization. NCT01290419.
[Show abstract][Hide abstract] ABSTRACT: Transcutaneous immunization (TCI) is continually evolving as an alternative vaccination strategy by targeting the skin immune system. Our laboratory has pioneered two major applications for TCI: (i) a needle-free vaccine patch in which antigen(s) and adjuvant are co-delivered by a patch, and (ii) a vaccine enhancement patch, which is used in combination with an injected vaccine and through which only an adjuvant is delivered on the skin. While the proof-of-concepts of TCI have been demonstrated in numerous animal studies, several recent clinical studies have now come to public notice, demonstrating that vaccine antigens can be delivered topically on the skin to induce immune responses. We provide current perspectives on skin immunology and TCI mechanisms, elaborate on lessons learned from preclinical TCI studies, and present key findings of recent clinical applications of TCI. In addition, we describe recent technical breakthroughs in developing a late-stage, integrated dry vaccine patch delivery system.
[Show abstract][Hide abstract] ABSTRACT: Transmission of pathogenic avian influenza viruses (AIV) from wild birds to domestic poultry and humans is continuing in multiple countries around the world. In preparation for a potential AIV pandemic, multiple vaccine candidates are under development. In the case of H5N1 AIV, a clear shift in transmission from clade 1 to clade 2 viruses occurred in recent years. The virus-like particle (VLP) represents an economical approach to pandemic vaccine development. In the current study, we evaluated the humoral immune response in humans vaccinated with H5N1 A/Indonesia/05/2005 (clade 2.1) VLP vaccine manufactured in Sf9 insect cells. The VLPs were comprised of the influenza virus hemagglutinin (HA), neuraminidase (NA), and matrix 1 (M1) proteins. In an FDA-approved phase I/II human clinical study, two doses of H5N1 VLPs at 15, 45, or 90 μg HA/dose resulted in seroconversion and production of functional antibodies. Moreover, cross-reactivity against other clade 2 subtypes was demonstrated using virus neutralization assays. H5N1 whole-genome fragment phage display libraries (GFPDL) were used to elucidate the antibody epitope repertoire in postvaccination human sera. Diverse epitopes in HA1/HA2 and NA were recognized by postvaccination sera from the two high-dose groups, including large segments spanning the HA1 receptor binding domain. Importantly, the vaccine elicited sera that preferentially bound to an oligomeric form of recombinant HA1 compared with monomeric HA1. The oligomeric/monomeric HA1 binding ratios of the sera correlated with the virus neutralizing titers. Additionally, the two high-dose VLP vaccine groups generated NA-inhibiting antibodies that were associated with binding to a C-terminal epitope close to the sialic acid binding site. These findings represent the first report describing the quality of the antibody responses in humans following AIV VLP immunization and support further development of such vaccines against emerging influenza virus strains.
Full-text · Article · Aug 2011 · Journal of Virology
[Show abstract][Hide abstract] ABSTRACT: Virus-like particles (VLPs) can be rapidly developed from influenza virus genetic sequences in order to supply vaccine after the onset of a pandemic. The safety and immunogenicity of one or two doses of a recombinant A (H1N1) 2009 influenza VLP vaccine was evaluated in a two-stage, Phase 2, randomized, double-blind, placebo-controlled study conducted in 4563 healthy adults, 18-64 years of age, during the H1N1 2009 pandemic in Mexico. In Part A, 1013 subjects were randomized into four treatment groups (5 μg, 15 μg, or 45 μg hemagglutinin [HA] VLP vaccine or placebo) and vaccinated 21 days apart, with sera collected on Days 1, 14 and 36 for hemagglutination inhibition (HAI) testing. After review of safety and immunogenicity data from Part A, additional subjects were immunized with a single dose of 15 μg VLP vaccine (N=2537) or placebo (N=1011) and assessed for safety in Part B. Results showed the H1N1 2009 VLP vaccine was safe and well-tolerated. Systemic solicited events were similar between placebo and VLP vaccinated groups with no vaccine-related serious adverse events. Dose response trends for solicited local adverse events were observed, with higher incidences of local pain, swelling, tenderness, and redness reported in the higher VLP dose groups (15 μg and 45 μg) compared to the placebo and 5 μg VLP groups following both vaccinations. Although the majority of local AEs were mild in severity, a dose trend in events of moderate or greater severity was also noted for these solicited events. The VLP vaccine groups demonstrated robust HAI immune responses after a single vaccination, with high rates of seroprotection (≥ 40 HAI titer) in 82-92% of all subjects and in 64-85% of subjects who were seronegative at the time of immunization. HAI geometric mean titers (GMTs), geometric mean ratios (GMRs) and seroconversion rates were also all statistically higher in the VLP groups compared to placebo for both post-baseline time points. Based on these data, additional clinical trials are in development to evaluate influenza vaccine candidate antigens manufactured using Spodoptera frugiperda (Sf9)/baculovirus-based VLP technology.
[Show abstract][Hide abstract] ABSTRACT: The use of adjuvants to enhance the immune response to novel pandemic influenza vaccine candidates may overcome the poor immune responses seen in immunologically naïve populations. The confluence of a highly pathogenic H5N1 influenza virus and the widespread absence of pre-existing immunity has driven the search for effective strategies for immunization in the face of a lethal pandemic. The potent adjuvant, heat labile enterotoxin from E. coli (LT), placed over the immunization site in a patch, is a novel adjuvant strategy for immune enhancement, and was evaluated using an H5N1 injectable vaccine.