New clinical trial designs for HIV vaccine evaluation.

PURPOSE OF REVIEW: With multiple HIV vaccine candidates suitable for efficacy evaluation in a rapidly changing HIV prevention landscape, innovative HIV vaccine trial design research is much needed to optimally utilize resources by building on lessons learned from past HIV vaccine efficacy trials. RECENT
FINDINGS: Several recent articles propose new vaccine efficacy trial design strategies tailored to the emerging needs in HIV vaccine evaluation. These include a focus on efficacy evaluation proximal to the vaccination series; more intensive interim monitoring for potential harm, nonefficacy and high efficacy of the vaccine; simultaneous evaluation of multiple vaccine regimens with a shared placebo group; designs that include pilot immunogenicity studies of putative immune correlates to expedite their evaluation; as well as designs tailored to evaluate vaccine efficacy in the context of partially effective nonvaccine prevention modalities.
SUMMARY: A more rapid evaluation of multiple vaccine candidates is possible. Weaker vaccines can be weeded out quickly. Pilot studies can be done during the trial to prepare for a timely immune correlates assessment. Evidence that emerges regarding the efficacy of nonvaccine prevention modalities will have important implications for future trial designs.