Oral Abstract Session 01 - Global HIV Vaccine Enterprise

POSTERS
Posters
Topic 4: Clinical Vaccine Trials and Trial Site Challenges
P04.11
Immunogenicity of a Universal HIV-1 Vaccine
Vectored by DNA, MVA and CHADV-63 in a Phase I/
IIA Clinical Trial
N.J. Borthwick 1 , T. Ahmed 1 , A. Rose 1 , U. Ebrahimsa 1 , A. Black 1 ,
E. Hayton 1 , H. Yang 1 , G. Hancock 1 , S. Campion 2 , N. Frahm 3 ,
S. Colloca 4 , A. Nicosia 4 , A. McMichael 5 , L. Dorrell 5 , T. Hanke 1
1 University of Oxford, Oxford, United Kingdom (Great Britain);
2 University of Oxford, Human Immunology Unit, Oxford,
United Kingdom (Great Britain); 3 HIV Vaccine Trials Network,
University of Washington, Seattle, USA; 4 Okairos, Rome, Italy;
5 Oxford University, Human Immunology Unit, Oxford, United
Kingdom (Great Britain)
Background: The major challenge facing both antibody and T
cell-eliciting vaccines against HIV-1 is the extreme variability of
the HIV-1 genome: a successful vaccine has to effectively target
diverse HIV-1 strains circulating in the population and then must
deal with ongoing virus escape in infected individuals. To address
these issues, we assembled a vaccine immunogen HIVconsv from
the functionally most conserved regions (not epitopes) of the
HIV-1 proteome.
Methods: A gene coding for the HIVconsv immunogen was
inserted into plasmid DNA (D), modified vaccinia virus Ankara
(MVA; M) and non-replicating adenovirus of a chimpanzee origin
ChAdV-63 (C). Currently, combined heterologous prime-boost
regimens of these vaccines, namely CM, DDDCM and DDDMC,
are being evaluated in a phase I/IIa trial HIV-CORE002 in healthy
HIV-1/2-negative volunteers in Oxford
Results: Preliminary data indicate that the vaccines are well
tolerated and show high immunogenicity. Following the CM
regimen, vaccine-induced T cell frequencies reached a median
of 5150 (range 1475 to 16495) SFU/106 PMBC ex vivo one week
post MVA vaccination. DNA priming increased subsequent T cell
responses to ChAdV-63 vaccination (median: C 577 and DDDC
1328 SFU/106 PBMC) and ELISpot responses again peaked 1 week
following MVA (median 4500; range 2260-7960 SFU/106 PBMC).
Matrix analyses of the participants following CM vaccination
showed that T cells responded to a range of peptides across
the length of HIVconsv. The CM regimen elicited IFN-γ in both
CD4+ and CD8+ T cell subsets and polyfunctional (IFN-γ & TNF-α)
responses to HIVconsv peptides.
Conclusion: Presented data will be very much work in progress.
Nevetheless, the HIVconsv vaccines have so far induced T cell
responses superior to other HIV-1 vaccine candidates tested to
date. ChAdV-63 is the first adenovirus of chimp origin delivering
an HIV-1-derived immunogen that has reached the clinic.
The work is supported by Medical Research Council UK.
154
AIDS Vaccine 2012
P04.12
Using an Internet Consumer Marketing Strategy to
Reach Men Who Have Sex with Men for Participation
in a Preventive HIV Vaccine Clinical Trial
C.D. Voytek 1 , K.T. Jones 1 , B.L. Curtis 2 , D.T. Fiore 1 , D. Dunbar 1 ,
I. Frank 3 , D.S. Metzger 1 , The NIAID HIV Vaccine Trials Network 1
1 University of Pennsylvania, Philadelphia, PA, USA; 2 University
of Pennsylvania Annenberg Public Policy Center, Philadelphia,
PA, USA; 3 University of Pennsylvania Perelman School of
Medicine, Philadelphia, PA, USA
Background: Sustaining research subject recruitment in
biomedical HIV prevention trials requires continual innovation.
Since June 2009, the University of Pennsylvania HIV Vaccine
Trials Unit (UPenn HVTU) has employed multiple strategies to
recruit men who have sex with men (MSM) for a phase IIb HIV
vaccine trial, HVTN 505.
Methods: Between 12/1/2011 and 1/3/2012, the HVTU
contracted with a consumer marketing company to recruit
potential trial participants. For $3000, the company emailed
MSM a scripted message inviting them to participate in a clinical
HIV vaccine trial, and the company provided the trial site with
contact information for those who responded. Site staff emailed
and phoned each respondent to provide study information and
conduct a phone-screen interview for the trial. Those eligible
were scheduled for in-office screening appointments.
Results: 266 MSM were emailed; 118 viewed the message, and
109 responded that they were interested in participating. 83%
of responders were White, and 71% earned >$50,000/year.
Staff successfully contacted 64 individuals, and 58 completed
phone-screens. Of these, 17 were eligible for, and 9 completed,
screening visits. Five enrolled in HVTN 505 during January-
February, 2012. Of 41 phone-screened ineligible, primary
reasons for ineligibility were: being HIV-positive (n=20; 49%),
not meeting protocol-specified sexual risk criteria (n=11; 27%),
out of age range (n=6; 15%), and/or being uncircumcised (n=5;
12%). Ineligible participants were referred to phase I or future
prevention trials as appropriate.
Conclusion: This strategy reached MSM not engaged by previous
efforts, and doubled site HVTN 505 enrollment over two months.
Respondents included a higher proportion of White MSM
than the population screened for HVTN 505 at the HVTU. This
approach has wider potential use for recruitment in biomedical
HIV prevention trials. To understand the true utility of this
approach, respondent HIV risk data and financial costs associated
with this strategy must be carefully examined.