One of the profound changes stemming from the halt of vaccinations in the Phase IIB Step trial of Merck’s HIV vaccine candidate is a redirection and reinvigoration of the research agenda of the various organizations involved in HIV vaccine research. Key among these organizations, the HIV Vaccine Trials Network (HVTN) has revamped its scientific agenda in response to the Step results.
Between 1999 and 2008, the HVTN conducted 22 Phase IA trials, three Phase IIA trials, and initiated two Phase IIB trials of Merck’s HIV vaccine candidate (Step and Phambili). During this period, the focus of the HVTN had shifted from efficiently streamlining the process of systematically testing HIV vaccine candidates in Phase I/II trials to initiating efficacy testing of products that emerge through that process as promising. The results of the studies of the Merck HIV vaccine candidate have inspired a reassessment by the HVTN, with refinement and expansion of the key basic questions being addressed. Among the current areas of focus:
A Step Scientific Review Committee including outside scientists and the Step trial partners (Merck/HVTN/DAIDS) chaired by Dr. Bruce Walker has begun to consider proposals for studies using the stored samples and reagents used in the Step and Phambili trials. To date the committee has reviewed 20 proposals of which 13 have been approved to receive specimens. Some examples of such research include:
These ancillary studies and the ongoing analysis of Step and Phambili data provide a rich opportunity to advance our knowledge of the immunology of HIV. It may be that through the lack of efficacy of an experimental vaccine the field of HIV vaccine research will take its greatest step forward.
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Last Updated June 01, 2009