WedSeattle, Washington, November 7, 2007, The AIDS Vaccine Advocacy Coalition (AVAC) released the following statement today from Executive Director Mitchell Warren in response to the release of new data from the STEP AIDS vaccine study by Merck & Co., the US National Institute for Allergy and Infectious Diseases (NIAID) and the HIV Vaccine Trials Network (HVTN) at a public forum at the HVTN meeting today.
The data from the STEP study released today confirm that the vaccine was not effective at either preventing infection in male volunteers or at reducing viral loads in male vaccine recipients who became infected with HIV during the trial. In addition, the data suggest that the vaccine may have made some volunteers more susceptible to acquiring HIV infection. The vaccine itself does not cause HIV. This trend was specifically observed among male volunteers who had high titers of antibody to adenovirus, the cold virus that was used, in a disabled form, in the MRK-Ad5 vaccine candidate.
“These data are deeply disappointing and troubling, and raise more questions than answers for the field of AIDS vaccine. Today’s discussion of the data underscores the leadership and transparency that Merck, NIAID, and HVTN continue to show in this complex and challenging time. What is clear is that the field must continue to work on this challenge and on the larger goal of finding a safe and effective AIDS vaccine.
“As much as we would like to see a clear answer in these results to whether or not the vaccine made some volunteers more susceptible to HIV infection, the reality is that there is still significant confusion about the underlying explanation for the observed effect.
“As we move forward, the work of analyzing and interpreting the data from the STEP study, and from the companion Phambili study in South Africa, will become even more difficult and even more important.
“In the weeks and months to come, we look to the AIDS vaccine field as a whole to maintain a collaborative spirit and to commit all necessary resources to the critical work of understanding the potential explanations and implications for the trends observed in the STEP study.
“We commend the trial sponsors for their consistent commitment to the safety of the volunteers, which must be the top priority in this and every other HIV prevention trial. At every stage of this difficult process, trial sponsors and site-level staff must continue to clearly communicate key information about the data and the participants’ potential risk to volunteers at every site.
“AVAC recognizes that these data leave the AIDS vaccine field with a range of difficult decisions. Going forward, we believe that the wisest course of action is also the most cautious. To safeguard future trials and volunteers, the trial sponsors and the field as a whole should take as long as is needed to analyze the data and attempt to come to more definitive conclusions about what these new data mean, before beginning efficacy trials of other vaccine candidates.
“In addition, if there is the possibility that unblinding the STEP study and informing every participant about whether he or she received the placebo or the vaccine will provide an additional safeguard for participants, then this is the course of action that should be taken. AVAC believes that ultimately the decision about unblinding the trial should be guided by the participants’ own concerns and priorities.
“Above all, we must continue to see this for what it is: a major setback for the AIDS vaccine field, but one that can and must be overcome through rigorous scientific investigation, open communication with communities, and a firm commitment to the shared goal of reversing the course of the AIDS epidemic in our lifetimes.”
AVAC will continue to provide updates, analysis and resource materials at http://avac.org/pr_step_study.htm as the decision about unbinding the trial is made and as more analyses and data are released.