07/20/2012 02:42 pm ET Updated Sep 19, 2012

Follow the Science to the End of the AIDS Epidemic

This week, we witnessed a watershed in the global AIDS response: the U.S. Food and Drug Administration approved the first-ever drug to reduce the risk of sexually acquired HIV infection in adults. The approval couldn't have come at a more opportune time, just days before the International AIDS Conference in Washington, D.C., where world leaders and AIDS experts will discuss how to act on recent scientific breakthroughs and begin to end the epidemic.

The new approach, called pre-exposure prophylaxis, or PrEP, involves HIV-negative people at risk of HIV infection using a daily HIV treatment medication (in this case, tenofovir/emtricitabine, also known as Truvada or TDF/FTC), in combination with other safer sex practices, to help them stay free of the virus. While it won't be right for everybody, daily oral PrEP with TDF/FTC will be a vital new option for many people at risk for HIV. With some 2.5 million people still becoming infected with HIV every year, new tools like PrEP are urgently needed.

By acting on strong evidence in support of this daily PrEP regimen -- despite the objections of a small but vocal opposition -- the FDA provided a lesson for all of us working to end the AIDS epidemic. In a nutshell: Follow the science.

That simple maxim -- though less simple in practice -- applies to nearly everything we must do to shift the course of the epidemic. We now have more ways of preventing and treating HIV than ever before, and all of these tools will be needed in various combinations. But with so many options, and with limited resources to support them, we need to answer some essential questions: Which interventions, for which populations, at what time?

In many cases, the evidence may require big changes to the way we've done things in the past, and may mean halting certain initiatives in favor of others that could have a greater impact.

For example, many countries have devoted significant resources to broad anti-HIV awareness campaigns, without adequately investing in the needs of their citizens at highest risk, who are often most vulnerable and disenfranchised -- whether they be sex workers, people who inject drugs, gay men, young people or others. This needs to stop. We now have effective options that can meet the needs of each of these populations, and countries need to invest where it counts.

In some cases, though, we don't yet have all the evidence we need to make informed choices. PrEP is a perfect example. While data from clinical trials leaves no doubt that daily PrEP with TDF/FTC can reduce the risk of HIV infection, many questions remain about its use in the real world.

For example, the multiple clinical trials showed that close adherence to the daily regimen is essential to its effectiveness. When participants didn't take their pills, they did not benefit from additional protection. For PrEP to have a significant impact, we need to understand how best to help people adhere to their daily regimen. We also need to understand how best to integrate PrEP with other proven HIV prevention strategies, how to get it into the hands of people at greatest risk, and how to ensure that they don't increase their HIV risk behaviors, since PrEP is not 100 percent effective at preventing infection.

To answer these questions, we need to quickly launch real-world demonstration projects that examine the use of TDF/FTC as PrEP in many different populations and settings -- in the U.S. and internationally. Yet right now, more than a year after the approach was shown to be effective in clinical trials, few such projects are funded or underway.

Demonstration projects like these are among the short-term priorities laid out in a new report this week from AVAC and our colleagues at amfAR. The report presents a three-year, global action agenda to set the world on a path toward ending AIDS. It sets specific, year-by-year priorities through 2015 to capitalize on the many effective HIV prevention methods now available, from voluntary medical male circumcision to antiretroviral treatment for people with HIV, which can help them avoid transmitting HIV to others. It also focuses on next steps in continued research and development for effective HIV vaccines and a cure, additional options that will ultimately be essential to end the epidemic.

A key theme of the report is that hard choices will be necessary -- but that we can achieve dramatic progress if we set evidence-based priorities and stick to them.

In fact, our analysis of modeling studies and other available data suggests the world could soon reach a "tipping point" in the AIDS epidemic, at which -- for the first time ever -- the number of people gaining access to HIV treatment outpaces the number becoming newly infected. This could be achieved in as little as two or three years if the right steps are taken now, and would be a major step in beginning to bring the epidemic under control.

We'll be highlighting the new action agenda throughout the upcoming conference, and are urging other stakeholders to commit to its targets.

I'm optimistic that, decades from now, we'll look back at July 2012 as the point at which the world began its successful drive to end one of humanity's greatest tragedies. If I'm proven right, it will because we not only had the right tools, but also knew how to use them.