AIDS vaccine developers do not, as a rule, set favorable pre-clinical monkey data as the sole basis for a go/no-go decision on whether to move forward in human trials. At the same time, favorable data can provide an important signal for advancing into product development. Monkey studies can provide critical immunological data hinting at how, not just whether, a vaccine might work in humans.

A new monkey study, Protective efficacy of adenovirus-protein vaccines against SIV challenges in rhesus monkeys, published July 2 in the journal Science sheds new light on a vaccine candidate being developed by Janssen Pharmaceuticals, part of Johnson & Johnson. The study was led by Dan Barouch from Beth Israel Deaconess Medical Center and the Ragon Institute of Massachusetts General Hospital, MIT and Harvard.

While the new data are from an animal model, the candidate vaccine strategy—Adenovirus type 26 (Ad26) and Modified Vaccinia Ankara (MVA) as vectors, in combination with an envelope (env) protein boost—is also being tested in humans in a Phase 1/2a international clinical study. (On AVAC’s recent webinar—Vaccines in Vivo: Advances in AIDS Vaccine Research—Janssen’s clinical head for HIV vaccines provided an overview of their research and development program, and the link provides a recording of his presentation and slides.)

The preclinical studies just published showed complete protection in half of the rhesus monkeys after six rectal challenges with SIV, a virus similar to HIV that infects monkeys. Similar adenovirus-based candidates have not demonstrated this degree of protection. These studies also showed the env protein boost enhanced antibody FC effector functions, which is believed to be a key factor in the functionality of antibody responses.

While these data are encouraging, the important work of testing this vaccine in human clinical trials is just beginning. So perhaps even more exciting than these preclinical results is that the corporate partner (Janssen) is actively engaged in funding the current human trial and seems committed to continued investment—and it has been almost a decade since a large vaccine developer invested significantly in clinical trials for AIDS vaccine development.

Today is HIV Vaccine Awareness Day. For our full 2015 Toolkit, click here. This blog, by Mitchell Warren AVAC’s Executive Director, first appeared on The Hill.

In 1995, nine HIV treatment activists joined together to speed the search for an AIDS vaccine. With the global epidemic raging and truly effective HIV treatments still unavailable, they focused their advocacy on the research institutions best positioned to drive new breakthroughs, especially the US National Institutes of Health (NIH).

Two decades later, the movement they started has achieved remarkable success. The search for an effective vaccine is in its most promising phase ever, with some 30 different candidates in the pipeline reflecting an exciting array of scientific approaches. A series of related advances – from early antiretroviral therapy (ART) to a daily prevention pill – are already transforming the global AIDS response and saving lives. For the first time, we can honestly talk about how to end the AIDS epidemic – and we have not only researchers, advocates, and trial participants to thank, but also American taxpayers.

But we don’t yet have all the tools we need. That’s why it is dismaying that some members of Congress have chosen this moment to call for scaling back the nation’s investments in HIV research. Instead, we should be looking for ways to make these investments even more impactful, to continue leading the world into a future without AIDS.

The threat to research investments is partly the product of their success. In 2005 and 2006, NIH-funded trials found that male circumcision can reduce a man’s risk of HIV infection by nearly two-thirds. In 2011, a landmark NIH study found that ART slashes the risk of HIV transmission by 96 percent. Beginning in 2010, a series of trials backed by NIH and the US Centers for Disease Control and Prevention showed that daily use of an HIV treatment medicine by people who are HIV-negative can reduce their risk of becoming infected by 90 percent or more.

It’s these advances that led to widespread talk of the “end of AIDS.” In hindsight, that talk might have backfired, creating the misperception that we can begin to ease up on the accelerator.

In fact, about 2.1 million people still become infected with HIV every year, including 50,000 in the United States. With current prevention options we can get that number way down – but nowhere near zero. The NIH’s own Anthony Fauci has spoken compellingly about how, in any realistic scenario, an effective vaccine and other new prevention tools are still essential to halt new HIV infections.

A vaccine isn’t just needed, it’s also very possible. Just this year, researchers launched studies that could lead to the first vaccine licensed for use. While it won’t be the perfect vaccine, it could make a real difference if proven to be even partially effective.

Meanwhile, basic science is opening up whole new areas of vaccine discovery, such as use of “broadly neutralizing antibodies.” These are immune system proteins that emerge in some people who are already infected HIV. Now, researchers are figuring out how to engineer them in the lab and offer them to HIV-negative people as a way to protect against infection. A whole range of other strategies are also in development, in the lab or in early human trials.

Dr. Fauci has done an admirable job of arguing for sustained research into AIDS vaccines and other approaches. But we can’t rely on any single voice to make our case. The entire AIDS community needs be speaking out in support of smart, strategic and well-funded HIV prevention research programs.

Within Congress itself, remaining backers of HIV research must stand up for the programs they’ve supported in the past. They need to make the case to colleagues, and the nation, for sustaining this work until the job is done. And they need to hold the research community accountable for making the most strategic use of taxpayer resources.

My organization is the product of the nine advocates who came together 20 years ago. Like HIV prevention itself, we’ve changed in unexpected ways. But the basic idea remains the same – that an effective AIDS vaccine is essential to ending one of modern humanity’s greatest tragedies. This is an idea we’ll be repeating on HIV Vaccine Awareness Day, May 18, and throughout the year.

The future path of science is never clear. But we can be certain that slowing down now would be a huge mistake – for American scientific leadership, and for millions of people whose lives depend on it.

Warren is Executive Director of AVAC, an advocacy organization for the elimination of HIV/AIDS.

The AIDS vaccine field has been energized by the recent launch of early clinical trials in South Africa – trials that could eventually lead to the first vaccine licensed for use. The vaccine being tested is a modified and hopefully improved version of the first and only AIDS vaccine candidate thus far to show moderate efficacy in preventing HIV infection in the RV144 trial in Thailand that finished in 2009.

This vaccine candidate will only move to large-scale efficacy trials – which are the prerequisite for licensure – if researchers decide it has a good chance for success. How will they know, and when will they know it?

The answers were outlined for advocates by the HVTN’s Glenda Gray on the AVAC webinar to mark HIV Vaccine Awareness Day (HVAD) 2015.

Gray discussed an ongoing trial of the ALVAC-protein vaccine candidate, HVTN100, which started in January 2015 in South Africa. By June 2016, there should be 12 months of data available about what kind of response the vaccine triggered among the 210 participants who received the experimental vaccine.

The specific requirements are quite technical, but basically the researchers will look at 12-month immune responses in HVTN100 and gauge the likelihood that the vaccine would maintain at least 50% efficacy for two years in the future efficacy trial. The Thai trial showed 31% efficacy overall. So if all goes according to plan in terms of timing and reaching a “go” decision, a vaccine efficacy trial with this ALVAC-protein prime-boost could start in early 2017.

On the webinar Gray also provided an update on the other planned HVTN clinical trials as part of the P5 partnership, as well as a new collaboration with the HIV Prevention Trials Network (HPTN) to advance one of the broadly neutralizing antibodies (bNAbs) into a possible efficacy trial as passive antibody prevention.

Also on the call Frank Tomaka of Janssen Pharmaceuticals, part Johnson & Johnson, presented their plans for clinical trials of his company’s new mosaic AIDS vaccine candidate using adenovirus type 26 as the vector. The suite of current trials that would lead to a possible efficacy trial in 2017 represent a significant investment by the company and welcome return of pharmaceutical industry financial investment in AIDS vaccine product development.

Finally, Bill Snow of the Global HIV Vaccine Enterprise reflected on the exciting progress in the field: after frustrating delays, we are now seeing clinical trials evaluating a trio of different approaches – ALVAC pox-protein, Ad26 mosaic, and bNAbs – that could move into efficacy trials in the coming 18-24 months. See AVAC’s new infographic for a visual display of this energized field.

An audio recording of the webinar and the presenters’ slides can be found here.

Ugandan advocate, Sylvia Nakasi joined the rest of the world to commemorate HIV Vaccine Awareness Day on May 18 by writing a thoughtful opinion piece in the New Vision. In her piece, Sylvia highlights how far HIV vaccine research and devlopment has come and calls for the need for continued investments in the search for an effective HIV vaccine. Sylvia also underscores the need to ensure that the options that are currently available – including treatment, voluntary counseling and testing, voluntary medical male circumcision, male and female condoms, pre-exposure prophylaxis (PrEP) etc – reach the people who need them the most. Sylvia is a Policy and Advocacy Officer at Uganda Network of AIDS Service Organisations (UNASO) and was an AVAC Advocacy Fellow in 2011.