IAS 2019: Promising HIV Vaccine Study Results Point to the Need to Intensify and Accelerate Preparation for Future Research and Access Challenges

Mexico City, Mexico – The Global HIV Vaccine Enterprise welcomes the important and encouraging results of the ASCENT study and new clinical data from the APPROACH study presented at the 10th IAS Conference on HIV Science (IAS 2019), held in Mexico City, Mexico. These two studies build on the success of previous research using mosaic-based vaccines and provide important data to inform ongoing efforts to develop an effective, implementable vaccine regimen – a central part of a comprehensive, global HIV prevention strategy.

This week in Mexico City, researchers from APPROACH presented long term (144 weeks) follow-up safety and immunogenicity data from 65 participants vaccinated with the study vaccines (Ad.26Mos.HIV and clade C gp140). The study showed that the regimen remained safe and elicited a humoral response at week 144 (96 weeks post last immunization) similar to that observed at week 96 (48 weeks post last immunization). Antibody titers in this human study were higher than those observed in a parallel study in non-human primates at week 72, which afforded protection against SHIV challenges.

Data from the ASCENT study showed that immunisation regimens (participants were primed with two doses of tetravalent Ad26.Mos4.HIV followed by two doses of tetravalent Ad26.Mos4.HIV and either Clade C gp140 plus adjuvant or a combination of mosaic and clade C gp140 plus adjuvant) were well tolerated. Vaccination with a combined mosaic/Clade C gp140 improved the breadth of the immune response.

Taken together, these data suggest that a four-immunisation vaccine regimen based on these components may lead to durable immune responses that are improved with the addition of a mosaic gp140. The next study to begin, aptly named Mosaico (HPX3002/HVTN 706), will investigate the efficacy of this vaccine regimen starting in 2019. This new study will complement the ongoing Imbokodo (HPX2008/HVTN 705) study and, together with other efficacy trials now underway (HVTN 702/Uhambo and PrEPVAcc), bring the field closer to the possibility of a successful HIV vaccine.

Now, with multiple efficacy-stage vaccine studies underway, new vaccine concepts progressing in the pipeline, and the end goal of an effective vaccine regimen against HIV closer than ever, the HIV vaccine research and development field faces the urgent need to prepare to build on these and future trial results. This includes planning for any study outcome; understanding regulatory pathways to licensure; aligning on preferred product characteristics to focus product improvement efforts; developing access strategies aligned with regional needs; and identifying resources to ensure access to any future vaccine for those in resource poor settings.

“As the HIV prevention field evolves, we have learned that real-world obstacles to the implementation and use of new prevention strategies present numerous challenges that can prevent access to and the use of potentially lifesaving prevention tools,” said Linda-Gail Bekker, past president of the International AIDS Society, chair of the Global HIV Vaccine Enterprise Advisory Group, and director of the Desmond Tutu HIV Centre at the University of Cape Town. “It is clear that a successful HIV vaccine would face similar if not greater challenges. Planning for success means minimising delays and optimising the future impact of vaccines currently in studies or in development.”

“Several epidemiological models have shown that even a partially effective HIV vaccine could reduce infections and be cost effective, while a highly effective vaccine would make an even greater impact” said Global HIV Vaccine Enterprise Director Roger Tatoud. “Regardless of study outcome, however, redoubling our collaborative efforts, learning from trial results, and expanding investment across the field remain essential to the development of an impactful and accessible HIV vaccine.”

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About the Enterprise

Established in 2003, The Global HIV Vaccine Enterprise (the Enterprise), a part of the International AIDS Society (IAS), unites stakeholders to share knowledge, foster collaboration, enable solutions, and expand support critical to the development of—and future access to—an HIV vaccine.

About APPROACH and ASCENT

APPROACH (HIV-V-A004/IPCAVD 009/NCT02315703) is a Phase 1/2a study in 393 healthy HIV-uninfected adults in the U.S., Rwanda, Uganda, South Africa and Thailand. It is evaluating the safety, tolerability and immunogenicity of various mosaic-based vaccine regimens for HIV-1.

ASCENT (HPX2003/HVTN118/IPCAVD012/NCT02935686) is a Phase 1/2a Study in 152 in healthy HIV-uninfected adults in the U.S., Rwanda, and Kenya. The primary purpose of this study is to assess the safety/tolerability and envelope (Env) specific immunogenicity of the two different mosaic-based vaccine regimens (one regimen containing a Clade C gp140 soluble protein, and one containing a combination Clade C/Mosaic gp140, both with aluminium phosphate adjuvant) and to assess envelope (Env)-binding antibody (Ab) responses of the 2 different vaccine regimens.

Janssen’s partners on the APPROACH and ASCENT study included Beth Israel Deaconess Medical Center (BIDMC), Harvard Medical School; the United States Military HIV Research Program (MHRP) at the Walter Reed Army Institute of Research (WRAIR), with the Henry M. Jackson Foundation for the Advancement of Military Medicine (HJF); the National Institute of Allergy and Infectious Diseases (NIAID), part of the US National Institutes of Health (NIH); the Ragon Institute of Massachusetts General Hospital, MIT and Harvard; the HIV Vaccine Trials Network (HVTN). The International AIDS Vaccine Initiative (IAVI) also supported APPROACH.