PrEPVacc (PV1): A Phase IIb three-arm, two-stage HIV prophylactic vaccine trial with a second randomization to compare TAF/FTC to TDF/FTC as pre-exposure prophylaxis.
Clinical Trial Design Summary
PrEPVacc is an international, multicentre, double-blind vaccine study with a three- arm prospective 1:1:1 randomisation comparing each of two experimental combination vaccine regimens with placebo control:
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DNA-HIV-PT123 and AIDSVAX® B/E (weeks 0,4,24,48)
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DNA-HIV-PT123 and CN54gp140+MPLA-L (weeks 0,4), then MVA-CMDR and CN54gp140+MPLA-L (weeks 24,48)
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Placebo (weeks 0,4,24,48)
In addition, it has a concurrent 1:1 randomisation component comparing two PrEP regimens, open-label:
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Daily TDF/FTC
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Daily TAF/FTC
During the progress of the trial, the Independent Data Monitoring Committee will review an interim analysis of vaccine efficacy to determine whether each active vaccine arm has demonstrated sufficient efficacy to warrant further investigation. This analysis will only consider new infections arising after the week 26 visit and only those in individuals who have completed the first three immunisations. The interim analysis will take place after 7 of these infections have occurred in the placebo group.
If both experimental arms continue as planned the study will recruit 556 participants to each arm, a minimum of 1668, each followed for a minimum of 74 weeks from enrolment. The PrEP analysis will consider new infections through to the week 26 visit in individuals who were HIV negative at enrolment.
Primary Outcome Measure(s)
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Efficacy Outcome for the vaccine analysis: HIV acquisition by a participant who completed the first three immunisations and was HIV negative at week 26.
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Efficacy Outcome for the PrEP analysis: HIV acquisition at or before week 26 by a participant who was HIV negative at enrolment.
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Safety Outcome: A clinical decision to discontinue the vaccine or PrEP regimen for an adverse event that is considered related to product.
Study completion and results are expected in 2024.
