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Gurwith M.,Paxvax, Inc. | Lock M.,Paxvax, Inc. | Taylor E.M.,Paxvax, Inc. | Ishioka G.,Paxvax, Inc. | And 8 more authors.
The Lancet Infectious Diseases

Background: Replication-competent virus vector vaccines might have advantages compared with non-replicating vector vaccines. We tested the safety and immunogenicity of an oral adenovirus serotype 4 vector vaccine candidate (Ad4-H5-Vtn) expressing the haemagglutinin from an avian influenza A H5N1 virus. Methods: We did this phase 1 study at four sites in the USA. We used a computer-generated randomisation list (block size eight, stratified by site) to assign healthy volunteers aged 18-40 years to receive one of five doses of Ad4-H5-Vtn (107 viral particles [VP], 108 VP, 109 VP, 1010 VP, 1011 VP) or placebo (3:1). Vaccine or placebo was given on three occasions, about 56 days apart. Participants, investigators, and study-site personnel were masked to assignment throughout the study. Subsequently, volunteers received a boost dose with 90 μg of an inactivated parenteral H5N1 vaccine. Primary immunogenicity endpoints were seroconversion by haemagglutination-inhibition (HAI), defined as a four-times rise compared with baseline titre, and HAI geometric mean titre (GMT). We solicited symptoms of reactogenicity daily for 7 days after each vaccination and recorded symptoms that persisted beyond 7 days as adverse events. Primary analysis was per protocol. This trial is registered with ClinicalTrials.gov, number NCT01006798. Findings: We enrolled 166 participants (125 vaccine; 41 placebo) between Oct 19, 2009, and Sept 9, 2010. HAI responses were low: 13 of 123 vaccinees (11%, 95% CI 6-17) and three of 41 placebo recipients (7%, 2-20) seroconverted. HAI GMT was 6 (95% CI 5-7) for vaccinees, and 5 (5-6) for placebo recipients. However, when inactivated H5N1 vaccine became available, one H5N1 boost was offered to all participants. In this substudy, HAI seroconversion occurred in 19 of 19 participants in the 1011 VP cohort (100%; 95% CI 82-100) and eight of 22 placebo recipients (36%; 17-59); 17 of 19 participants in the 1011 VP cohort (89%; 67-99) achieved seroprotection compared with four of 22 placebo recipients (18%; 5-40); GMT was 135 (89-205) with 1011 VP, compared with 13 (7-21) with placebo. The cumulative frequency of abdominal pain, diarrhoea, and nasal congestion after all three vaccinations was significantly higher in vaccinees than placebo recipients (21 [16·8%] of 125 vs one [2·4%] of 41, p=0·017; 24 [19·2%] of 125 vs two [4·9%] of 41, p=0·027; 41 [32·8%] of 125 vs six [14·6%] of 41, p=0·028; respectively). No serious treatment-related adverse events occurred. Interpretation: Oral Ad4 vector priming might enhance the efficacy of poorly immunogenic vaccines such as H5N1. Funding: Wellcome Trust Foundation, PaxVax. © 2013 Elsevier Ltd. Source

Hopkins R.J.,Emergent BioSolutions | Howard C.,Emergent BioSolutions | Hunter-Stitt E.,Emergent BioSolutions | Kaptur P.E.,Emergent BioSolutions | And 6 more authors.

Background: This study was conducted to support licensure of a post-exposure prophylaxis indication for BioThrax® (anthrax vaccine adsorbed) concurrent with antimicrobials for individuals exposed to aerosolized anthrax spores. Methods: The immunogenicity and safety of a three-dose regimen (0, 2, and 4 weeks) of BioThrax administered subcutaneously (SC) were evaluated in 200 healthy adults 18-65 years of age. Toxin-neutralizing antibody (TNA) was expressed as 50% neutralization factor (NF50) at predetermined time points through Day 100. Safety was assessed by physical examinations, vital signs, solicited local and systemic reactions using web-enabled subject diaries, in-clinic solicited reactions, and unsolicited adverse events (AEs). Results: The prospectively defined success criteria for the primary and secondary endpoints were met. This required the lower bound of the 95% confidence interval (CI) for the proportion of subjects with a TNA NF50 value to be greater than 40% at Day 63 (primary), Day 70 (secondary) and Days 63-100 (secondary). At Day 63, 71% of subjects achieved a TNA NF50 threshold value ≥0.56, with a lower bound of the 95% CI ≥40% (64%). The percentage of subjects achieving a TNA NF50 threshold value ≥0.56 at Day 70 was 58% (95% CI: 50%, 65%), and the mean value on Days 63-100 (inclusive) was 53% (95% CI: 41%, 55%). The threshold TNA NF50 value of 0.56 was developed from previous rabbit challenge and human immunogenicity studies. No related serious AEs occurred during the study, and no subjects withdrew from the study because of an AE. Tenderness and pain at the injection site were recorded most often in subject diaries following vaccination. Conclusions: BioThrax, administered as three SC doses at 0, 2, and 4 weeks, was well tolerated. The prospectively defined success criteria for TNA levels on Days 63, 70, and 63-100 were achieved. © 2014 Elsevier Ltd. Source

Tsang P.,Sanofi S.A. | Gorse G.J.,Saint Louis University | Strout C.B.,Coastal Carolina Research Center | Sperling M.,Fountain | And 4 more authors.

We conducted a randomized, controlled, multicenter, phase II study to evaluate the immunogenicity and safety of an investigational intradermal (ID) trivalent influenza vaccine (TIV) and a high-dose (HD) intramuscular (IM) TIV in older adults (≥65 years of age). Older adult subjects were immunized with ID vaccine containing either 15μg hemagglutinin (HA)/strain (n=636) or 21μg HA/strain (n=634), with HD IM vaccine containing 60μg HA/strain (n=320), or with standard-dose (SD) IM vaccine (Fluzone®; 15μg HA/strain; n=319). For comparison, younger adults (18-49 years of age) were immunized with SD IM vaccine. In older adults, post-vaccination geometric mean titers induced by the ID vaccines were superior to those induced by the SD IM vaccine for the A/H1N1 and A/H3N2 strains and non-inferior for the B strain. Seroconversion rates induced by the ID vaccines were superior to those induced by the SD IM vaccine in older adults for the A/H1N1 and B strains and non-inferior for the A/H3N2 strain. Results did not differ significantly for the two ID vaccine dosages. Post-vaccination geometric mean titers, seroconversion rates, and most seroprotection rates were significantly higher in HD vaccine recipients than in older adult recipients of the SD IM or ID vaccines and, for most measures, were comparable to those of younger adult SD IM vaccine recipients. Injection-site reactions, but not systemic reactions or unsolicited adverse events, were more common with the ID vaccines than with the IM vaccines. No treatment-related serious adverse events were reported. This study demonstrated that: (1) the ID and HD vaccines were well-tolerated and more immunogenic than the SD IM vaccine in older adults; (2) the HD vaccine was more immunogenic than the ID vaccines in older adults; and (3) the HD vaccine in older adults and the SD IM vaccine in younger adults elicited comparable antibody responses (ClinicalTrials.gov identifier no.: NCT00551031). © 2014 The Authors. Source

Gorse G.J.,Saint Louis University | Falsey A.R.,Rochester General Hospital | Fling J.A.,University of North Texas Health Science Center | Poling T.L.,Heartland Research Associates | And 2 more authors.

Background: To increase vaccine acceptance, intradermal (ID) influenza vaccine (Fluzone® Intradermal, Sanofi Pasteur Inc.) may be an attractive alternative to intramuscular (IM) vaccination due to smaller needle and volume injected. Methods: A multicenter, randomized (2:1 ID vs IM vaccines) study, blinded for ID vaccine lots, was conducted among 4292 adults 18-64 years of age enrolled in October 2008. Three lots of investigational trivalent influenza vaccine containing 9. μg hemagglutinin (HA) per strain in 0.1 mL administered ID with a 30 gauge, 1.5 mm long needle were compared to standard dose vaccine (0.5 mL containing 15 μg HA/strain) given IM. Results: The post-vaccination antibody geometric mean titers (GMT) for the ID vaccine were similar to the IM vaccine (H1N1: 193.2 vs. 178.3, H3N2: 246.7 vs. 230.7, and B: 102.5 vs. 126.9). Non-inferiority was met for the ID vaccine compared to IM vaccine as assessed by antibody GMT ratios (IM/ID) for all three virus strains (H1N1: 0.92, H3N2: 0.94, and B: 1.24). Seroconversion rates were non-inferior for H1N1 and H3N2, but not for B (ID vs. IM: H1N1: 61.2% vs. 60.5%, H3N2: 75.3% vs. 74.8%, and B: 46.2% vs. 54.2%). Seroprotection (HAI titer ≥1:40) rates were similar between groups (ID vs. IM, H1N1: 91.1% vs. 91.7%, H3N2: 90.7% vs. 91.4%, and B: 87.4% vs. 89.3%). Local injection site reactions overall were more common with ID than IM vaccine (ID vs. IM: 89.2% vs. 60.2%), but were usually grade 1 or 2 and transient. The frequencies of local injection site pain and systemic reactions were similar between vaccine groups, except more myalgia with IM vaccine. Conclusions: The ID vaccine elicited immune responses comparable to IM vaccine except for the seroconversion rate to B virus. With the exception of pain, local injection site reactions were more common with the ID vaccine, but well-tolerated and of short duration. Trial registration: ClinicalTrials.gov identifier: NCT00772109. © 2013 Elsevier Ltd. Source

Greenberg R.N.,University of Kentucky | Gurtman A.,Pfizer | Frenck R.W.,Cincinnati Childrens Hospital Medical Center | Strout C.,Coastal Carolina Research Center | And 6 more authors.

Background: Unlike free pneumococcal polysaccharide vaccines (PPSVs), pneumococcal conjugate vaccines (PCVs) induce a T-cell-dependent immune response. The study assessed potential influence of initial 13-valent PCV (PCV13) or 23-valent PPSV (PPSV23) on subsequent vaccine administrations. Methods: We conducted a randomized, modified double-blind study in 720 pneumococcal vaccine-naïve adults 60-64 years of age. Subjects received either PCV13 at year 0 and PCV13 at year 1; PCV13 at year 0 and PPSV23 at year 1; or PPSV23 at year 0 and PCV13 at year 1. Antipneumococcal opsonophagocytic activity (OPA) titers were measured before and 1 month after each vaccination. Results: OPA titers following PPSV23 given 1 year after PCV13 (PCV13/PPSV23) (a) were noninferior for the 12 common serotypes and significantly higher for 6 of 12 common serotypes than those following only an initial PPSV23; and (b) were significantly higher for 11 of 12 common serotypes compared with PPSV23 followed by PCV13 (PPSV23/PCV13). In addition, PPSV23 followed 1 year later by PCV13 (PPSV23/PCV13) elicited significantly lower OPA titers than after only an initial dose of PCV13 for all 13 serotypes. Responses after a second vaccination with either PCV13 (PCV13/PCV13) or PPSV23 (PCV13/PPSV23) were noninferior for 9 of 13 and 8 of 12 common serotypes compared with the initial PCV13 dose. Conclusion: In pneumococcal vaccine-naïve adults 60-64 years of age, an initial PCV13 augmented the antipneumococcal response to subsequent administration of PPSV23 for many of the serotypes in common to both vaccines. In contrast, an initial PPSV23 resulted in a diminished response to subsequent administration of PCV13 for all serotypes. With a relatively short 1-year interval between doses, responses after a second vaccination with PCV13 (PCV13/PCV13) or PPSV23 (PCV13/PPSV23) were noninferior for a majority of serotypes compared with the initial PCV13 dose, probably reflecting the need for a longer interval between vaccine administrations.ClinicalTrials.gov Identifier: NCT00574548. © 2014 Elsevier Ltd. Source

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