NEW YORK, Sept. 21 The AIDS Vaccine AdvocacyCoalition (AVAC) released the following statement from Executive DirectorMitchell Warren about the announcement that vaccinations have beendiscontinued in the STEP Study, a test-of-concept trial of the MRK-Ad5 AIDSvaccine candidate developed by the Merck Research Laboratories:
"Today's announcement about the STEP Study is a deep disappointment and ascientific setback for the AIDS vaccine field. However, it must be seen forwhat it is: the failure of a product to show efficacy in a specific trial.Clinical testing of AIDS vaccines is a scientific process and, while this is adisappointment, it is in no way the end of the search for an AIDS vaccine.
"These data are certainly not the ones that we had hoped for. The entireHIV vaccine field, including AVAC, had been looking to STEP and its companionPhambili trial in South Africa, to provide initial evidence of vaccine-relatedbenefits. Even as the data disappoint, we also note the success of the STEPStudy trial design in providing a swift answer to the critical question ofwhether or not the vaccine provided any benefits. A successful clinical trialis one that produces a scientifically accurate result. It may not be theresult you had hoped for, but it answers questions that help the field moveforward.
"We applaud Merck's tremendous leadership on HIV vaccine research. Thecompany has set an example for the field, taking on one of the most importanthealth technology challenges of our time. Merck and its collaborator, the USNIH-funded HIV Vaccine Trials Network, have been committed, strategic andwilling to take risks at every stage of evaluating MRK-Ad5, and they must becommended for this. AVAC also recognizes the contributions of the thousands ofvolunteers in these trials. Their altruistic involvement makes HIV vaccineresearch possible. It is essential to build on what has been learned here andproceed with further research as rapidly as possible. Millions of lives are atstake.
"In the next weeks and months the AIDS vaccine field will need to makecarefully-considered decisions about whether to move forward with plannedtrials of related vaccine strategies, and how to proceed with the Phambilitrial, which has paused immunizations and enrollment. AVAC is committed toworking with many other stakeholders in the AIDS vaccine field and in otherareas of AIDS prevention research to ensure that these discussions arethoughtful, transparent, and clearly communicated to global audiences.
"These results do not change our fundamental view. Developing an AIDSvaccine will require a series of large-scale human trials in many differentcountries over a number of years. These trials need to be designed to produceclear results and to design better candidates in the future. This researchmust be complemented by ongoing studies of other new biomedical preventionstrategies, and by full-scale, fully-funded implementation of provenprevention and treatment strategies."
About the STEP Study
An interim analysis of data from the study, involving over 3,000 peopletesting an adenovirus-based vaccine (MRK-Ad5) developed by the Merck ResearchLaboratories, showed no efficacy in protecting against new infections or inreducing viral load in people who received the vaccine and went on to becomeinfected. The study was scheduled to end in 2009. Periodic reviews of data byan independent monitoring board are part of the clinical trials process, andthe study was halted on the recommendation of the STEP Study monitoring boardafter a regularly-scheduled review.
There have been two previous efficacy trials of an AIDS vaccine candidate,called AIDSVAX. Both of these studies took more than five years from launch toannouncement of the finding -- that the candidate did not protect againstinfection. The STEP Study enrolled its first participant in December 2004, andwe have