New York, NY – The announcement today that immunizations in a large-scale HIV vaccine trial have been stopped early after an independent scientific review board determined that the vaccine being tested is not effective is a reminder of how challenging it is to develop an effective AIDS vaccine, AVAC said. AIDS vaccine research is in its most promising period in decades with breakthroughs in a number of approaches different from that studied in 505. Even though the trial showed no benefit, analysis of these data will help refine the vaccine research pipeline.
The US National Institute of Allergy and Infectious Diseases (NIAID) announced today that the independent Data Safety and Monitoring Board for HVTN 505, a trial testing a two-part vaccine among 2,500 men who have sex with men and transgender women in the United States, recommended that the immunizations be stopped since the data showed that the trial would not be able to show vaccine efficacy. Follow-up of participants will continue.
“This trial has provided a clear, swift answer about a specific vaccine strategy. It’s not the answer we hoped for, but the search doesn’t end here. There are other approaches that must be pursued without delay, and this result will help to focus and guide research efforts,” said Mitchell Warren, AVAC executive director. “Researchers need to unpack the data from this trial to understand more about why this strategy didn’t prevent infection.”
HVTN 505 tested a two-part vaccine strategy including a series of DNA “prime” shots with a vaccine “boost” using a vector based on adenovirus type 5 (Ad5), a common cold virus. While a similar but distinct Ad5-vectored candidate failed to show efficacy in two previous trials, the vaccine tested in HVTN 505 had key differences that researchers hoped would overcome the limitations of earlier candidates.
The adenovirus-based vaccine in HVTN 505 is one of several AIDS vaccine approaches being studied. Vaccine concepts based on the successful RV144 vaccine strategy that showed modest efficacy in a large trial in Thailand in 2009 are moving toward efficacy trials in Thailand and South Africa. Researchers have also recently discovered a number of highly potent neutralizing antibodies and are working to translate these into future vaccine strategies.
“While today’s result is disappointing, we need to look at the bigger picture of AIDS vaccine science. Now more than ever, it is critical to maintain robust funding and establish clear timelines and milestones for the development of an HIV vaccine and other HIV prevention options that can help end the AIDS epidemic,” Warren said.
“At the same time, these results highlight that we must also ensure that all available existing prevention options are offered to those who want and can benefit from them – including male and female condoms, HIV treatment, voluntary medical male circumcision, and daily oral pre-exposure prophylaxis, or PrEP.” Warren said. “While a vaccine remains essential in the long-term fight to end AIDS, we can achieve substantial reductions in new HIV infections in the meantime with fully funded implementation of proven prevention and treatment strategies.”
“There will be many questions and concerns from trial participants, researchers, communities, advocates and others about what the data from HVTN 505 tell us,” Warren said. “NIAID, the trial’s sponsor, has specifically noted the need to understand the finding of slightly higher numbers of infections among vaccine recipients. This finding does not have statistical significance and does not mean that the vaccine increased the risk of HIV. But we do need to understand these data and communicate them clearly. The levels of transparency, urgency and concern that we have seen already from NIAID and HVTN remain crucial as the trial team examines the data and continues to closely monitor trial participants.”
“AVAC also recognizes the enormous contributions of the more than 2,500 volunteers in this trial. Their altruistic involvement makes HIV vaccine research possible. We owe it to them to understand and build on what has been learned here and proceed with further research as rapidly and strategically as possible. The trial staff have also done a huge amount of work and are to be credited for running such a good trial and getting us to an answer.”
“The news today about the halting the trial deeply saddens me as both an HIV vaccine advocate and 505 trial participant,” said Matthew Rose, a member of AVAC’s PxROAR HIV prevention advocacy program. “But I remain hopeful in our search for a vaccine, as this trial showed how researchers and communities can work together to recruit under-represented populations that have not been engaged in AIDS vaccine research. The trial offers a model for how research can be more reflective of the communities that carry the highest burden of HIV and could most benefit from an effective vaccine.”
“These results do not change the fundamental view that an AIDS vaccine remains critical to any long-term strategy to end the AIDS epidemic,” said Rose.
About AVAC: Founded in 1995, AVAC is a non-profit organization that uses education, policy analysis, advocacy and a network of global collaborations to accelerate the ethical development and global delivery of AIDS vaccines, male circumcision, microbicides, PrEP and other emerging HIV prevention options as part of a comprehensive response to the pandemic.