HIV activists have raised concern about the continued high rates of HIV infection in Africa and renewed calls for strengthening prevention strategies.
This follows another HIV vaccine trial that failed to make it through clinical trials – the Imbokodo study started in 2017 by big pharma Johnson and Johnson.
Ntando Yola, an HIV advocate with the Desmond Tutu Health Foundation, one of the organizations that have been working on the botched study in South Africa told journalists that they were perturbed by the number of people who got newly infected in that controlled setting.
Johnson & Johnson and partners today announced that the Imbokodo study also known as HVTN 705/ HPX2008, did not significantly reduce the overall risk of HIV acquisition among over 2,600 women.
Over a hundred women got infected. According to the Johnson and Johnson press release, data found that through 24 months of follow up, 63 of 1,109 participants received placebo compared to 51 of 1,079 participants who received active vaccine acquired HIV.
About the study:
The Imbokodo study evaluated whether an Adenovirus26-based mosaic vaccine regimen could safely and effectively reduce the rate of new HIV infections among 2,637 cisgender women in 23 sites in Malawi, Mozambique, South Africa, Zambia and Zimbabwe.
Participants received a total of four doses over 12 months of either a prime-boost vaccine regimen of a mosaic viral-vectored vaccine, Adeno26.Mos4.HIV (Ad26 prime) and an aluminum phosphate-adjuvanted clade C gp140 protein (boost), or a placebo.
The HIV vaccine was tested using the same platform (Adeno26) that the company used recently to develop their single-dose COVID-19, which has since been given an emergency use approval by the World Health Organization (WHO).
A statement featured by AVAC- a Global Advocacy For HIV Prevention organisation (AVAC) said while the Imbokodo results were disappointing, HIV vaccine research must continue.
Mitchell Warren, the head of AVAC told journalists that the trial only showed 25% effectiveness in preventing infection in HIV which means it was working very less effectively.
He however warned that this should not scare people away from the COVID-19 vaccine which is manufactured by the same company since HIV operates very differently from the SARS- COV 2 virus.
“We always hope that efficacy trials will show positive results that lead directly to new prevention options,” he said. “It is very disappointing that this particular vaccine candidate did not work in this trial, but the trial was well-conducted and got an answer quickly.”
Warren says data from this study only shows how desperately women in Africa not only need a vaccine but other prevention options. Over the years, several groups of researchers have been trying to find a vaccine but all efforts have so far been futile.
For instance, after a vaccine trial by another pharmaceutical company Merck failed in 2007, researchers got another impendent in 2009 after another study done in Thailand couldn’t produce results good enough for people to start taking HIV jabs. Efficacy among the people involved was estimated at 30%.
The most recent setback in the field of HIV vaccines was in February 2020 when a candidate by pharmaceutical companies Sanofi and GlaxoSmithKline involving more than 5,400 participants in Africa was stopped by an independent data monitoring board over efficacy issues too.
But even then, researchers continue searching as another vaccine study called PrEPVacc is currently being conducted in Masaka, Mbeya in Tanzania; Dar-es-Salaam, Tanzania, Maputo, Mozambique and Durban, South Africa. Results of this are expected in 2023.
“We applaud Johnson & Johnson for working in collaboration with the HIV prevention community, for their leadership in HIV vaccine research and for their longstanding commitment to Good Participatory Practices (GPP) that must be continued to maintain trust in vaccines and in research,” said Nandisile Luthuli, AVAC’s Regional Stakeholder Engagement Manager.
“This is in no way the end of the search for an HIV vaccine,” added Warren. “We still hope for a positive outcome from the ongoing Mosaico and PrEPVacc studies.
Yet, now more than ever, the vaccine field needs diversity and creativity — and even more collaboration — in deciding what comes next as research priorities as there are no other vaccine candidates currently on a clear track to licensure.
The field must focus on new hypotheses driven by this result and the recent antibody-mediated prevention study results, both of which showed some trends towards efficacy.
“Just as decades of HIV research paved the way for effective COVID-19 vaccines, HIV vaccine developers now need to draw on the creativity, speed, agility and decision-making of COVID-19 vaccine development in product development, trial design and regulatory pathways,” said Stacey Hannah, AVAC’s Director of Research Engagement.
“AVAC calls on donors, research groups and industry to join in strategic discussions with civil society and trial communities to map out a comprehensive strategy for the future of HIV vaccine research, product development and selection, and trial designs.
” A renewed commitment to this type of engagement within the HIV vaccine field would build on lessons learned from COVID-19 vaccine development and lead to a strategy that is coordinated, appropriately resourced, includes relevant target product profiles, and commits to share data across research groups and trials.
“For the last two decades, we have seen HIV prevention trials reporting annual incidence rates of four percent or higher among women trial participants in various East and Southern African countries.
Warren noted that there is still a moral and ethical obligation to provide women living in contexts of HIV risk with prevention options that work for them and the Imbokodo study is another reminder of the need to work harder and faster to roll out effective HIV prevention options at scale to the people who need them most.
Safe and effective HIV prevention options, including male and female condoms, voluntary medical male circumcision and daily oral PrEP are all available now but not rolled out to scale.
Additional prevention options are nearing availability, including the Dapivirine Vaginal Ring and injectable cabotegravir, and several next-generation PrEP options are now entering advanced clinical trials.
“As the Imbokodo study participants return for their final visits, it is essential that they not only receive the research results, but are offered access to all available prevention options, including oral PrEP – which is available in all countries where the trial took place – and linked directly to these services,” added Luthuli.
“In addition, the trial team and sponsors should explore innovative approaches to offering these trial participants the opportunity to enroll into new introduction projects offering the Dapivirine Vaginal Ring and injectable cabotegravir.
A companion study, the Phase III Mosaico trial, will continue. The Mosaico study uses a similar regimen with the same Ad26 platform for the prime vaccine, but using a different form of protein boost.
The Phase III study, also known as HVTN 706/HPX3002, is currently enrolling 3,800 men and transgender people in eight countries in the Americas and Europe.
While the Imbokodo study did not provide sufficient protection to continue, there were no safety concerns with the Adenovirus26-based mosaic vaccine candidate.
The Ad26 platform delivers a protein, known as an antigen, to stimulate an immune response. The platform has proven effective in other successful vaccines, including for Ebola and COVID-19.
There is every reason to have confidence in the effectiveness of the Ad26-based Ebola and COVID-19 vaccines that have been important in helping to curb Ebola outbreaks and blunt the current COVID-19 pandemic.