An “AIDS-free generation” may someday be possible. By Michael Smith, North American Correspondent, MedPage Today
MONDAY Dec. 26, 2011 (MedPage Today) — As part of the Year in Review series, MedPage Today reporters are revisiting major news stories and following up with an analysis of the impact of the original report, as well as subsequent news generated by the initial publication. Here’s what has happened on the HIV prevention front since we published our the first 2011 piece on the topic.
In the history of our time, 2011 could be remembered as the year the tide began to turn against the HIV/AIDS pandemic.
Equally, it could be remembered as the year we fumbled the opportunity to end one of our greatest scourges.
The key event was the release in May of data from a single randomized clinical trial — the 052 study by the HIV Prevention Trials Network (HPTN) — that showed that treating people with HIV reduced the risk of transmission by some 96 percent.
The study has been “catalytic,” according to principal investigator Myron Cohen, MD, of the University of North Carolina in Chapel Hill, N.C.
Perhaps the most public evidence of that catalysis was U.S. Secretary of State Hillary Clinton’s Nov. 8 speech at the NIH, arguing that the HPTN 052 results are a central part of the possibility of an “AIDS-free generation.”
But Cohen also cites policy changes that now emphasize “treatment as prevention” at the Joint United Nations Programme on HIV/AIDS (UNAIDS) and in the President’s Emergency Plan for AIDS Relief (PEPFAR). And several field studies have begun to show how to translate the HPTN 052 findings into community programs.
“It’s a massive amount of stuff in nine months,” Cohen told MedPage Today.
It’s a tribute, at least in part, to the care with which the study was done and to its potential impact. Science magazine, in its Dec. 23 issue, called the trial the most important scientific advance of the year.
Making Treatment More Universal
On the other hand, treatment as prevention only works if people with HIV are actually getting treated. The world is undeniably doing better than ever in that regard, with more than six million people on highly active anti-retroviral therapy (HAART) — but that still leaves many millions more without therapy.
And the Global Fund to Fight AIDS, Tuberculosis and Malaria — probably the most important organization pushing expanded HIV treatment — announced late in November that donor countries had failed to deliver more than $2 billion that they had promised.
As a result, the fund said, the next round of grants for new projects would be cancelled.
That is “totally unacceptable,” according to Julio Montaner, MD, of the British Columbia Centre for Excellence in HIV/AIDS.
Montaner, past president of the International AIDS Society, has been an advocate of universal HIV treatment for years and at times one of the loudest and most strident voices raised in favor of treatment as prevention.
That advocacy had two pillars. On one hand, Montaner had a doctor’s passionate conviction that treatment is vital for the health of the millions of people living with HIV around the world. On the other, he was more and more convinced that treatment would pay for itself in the long run, by preventing further infections.
He and others were slowly winning people over, with evidence from observational studies, mathematical modeling analyses, biological plausibility, and secondary data from randomized trials of other interventions.
“But there would be always people who are more or less purists,” he told MedPage Today. The purists wanted something definitive, something clear-cut. And that’s the role the HPTN 052 trial has played.
“HPTN 052 was clearly critical to silence a lot of the skepticism,” Montaner said. But the body of evidence beforehand was already “compelling (and) the field was quite ready to embrace it.”
Indeed, the week before the HPTN 052 results were released, Montaner and his Canadian colleagues played host in Vancouver to a treatment-as-prevention workshop, at which representatives of the World Health Organization said they were ready to recommend it for some groups.
And China, earlier this year, said it would incorporate the idea into its national HIV/AIDS program, Montaner said.
Essentially, he argues, the verdict is in. The basic thrust of HIV treatment is to reduce the amount of virus in a patient’s system. Proper treatment, taken properly, does that very effectively.
Stopping the Contagion
Most HIV transmission around the world is by sexual means, but HIV is not very efficient at getting itself transmitted that way. Reducing the viral load changes that relative inefficiency into an almost complete lack of efficiency.
“If people take the pills and adhere to the pills, they become very much non-contagious,” Cohen concurred.
So treatment works, both to keep individual patients healthy and to keep their partners HIV-free.
That’s why Montaner, like many others, was heartened by Clinton’s Nov. 8 speech, and then both disappointed and angered by the Global Fund shortfall.
And it’s why he says more study to translate the HPTN 052 results into the real world is not needed and may just delay matters. Universal treatment is “medically necessary and the world has committed to it,” he said. Beyond that is a secondary benefit — fewer people will become HIV-positive and over time the pandemic will fade.
“We all recognize that there is a gap between the efficacy you get in a clinical trial and the effectiveness that you see when you roll out the intervention in the community,” he said.
But it’s possible, Montaner said, to roll out a community intervention, monitor its effectiveness, and adjust if things aren’t working well. Indeed, since the world is a big place, different strategies could be tried in different places, with everybody learning from the most successful examples.
There’s no doubt that the HPTN 052 trial made history, as the dramatic capstone of years of research that — taken together — shows treatment yields nearly complete prevention. “If the effect had been 40 percent instead of 96 percent, we wouldn’t be having this conversation,” Cohen told MedPage Today.
But he said he has always been careful to point out a host of possible obstacles that in theory might limit the effectiveness of universal treatment as prevention:
- Detecting people with HIV and linking them to care is hard, even if drugs are available.
- Keeping them in care can be difficult.
- Drug resistance is always a possibility if people don’t take medication properly.
- Detecting and treating acute infection, during which people are most infectious, is problematic.
- And there are worries about so-called risk compensation, in which people — feeling that they are protected — alter their sexual behavior for the worse.
But like Montaner, he thinks those can be overcome.
“I look at them now more as challenges than as limitations,” Cohen said. “It’s silly to be too pessimistic.”