29 November 2010

HIV prevention drugs raise more questions than answers

Recent studies have shown that ARVs can reduce the risk of HIV-infection but for researchers and governments - the research raises more questions than answers.


Recent studies have shown that antiretroviral [ARV] drugs can reduce the risk of HIV-infection but for researchers and governments - the research raises more questions than answers about its implementation.

The New England Journal of Medicine recently published the results of a study to use antiretrovirals as pre-exposure prophylaxis (PrEP) to prevent HIV infection among men who have sex with men (MSM).

The iPrEx results come four months after Centre for the AIDS Programme of Research in South Africa (CAPRISA) researchers announced their tenofovir-based vaginal gel reduced HIV infections by 39% in study participants.

Pressure to roll-out new prevention methods

The result will be increased pressure on high HIV-prevalence countries such as South Africa to roll out prevention methods, according to Helen Rees, director of the Wits Institute for Sexual and Reproductive Health, HIV and Related Diseases.

Speaking at a debate on PrEP held by Johannesburg's University of the Witwatersrand on 25 November, Rees cautioned that while more research was needed, South Africa had to start thinking about how, when and to whom PrEP would be given.

Identifying the targets

Although ARVs are already used to prevent HIV infection in infants as part of prevention of mother-to-child HIV transmission (PMTCT) programmes and as post-exposure prophylaxis in HIV-exposed health workers, the debate highlights concerns about how widespread PrEP distribution would be financed, implemented and monitored.

Patients would need to be screened for HIV about every three months  in order to minimise the risk of drug resistance in those who aquired HIV, according to Lynn Morris, CAPRISA researcher and head of South Africa's National Institute for Communicable Diseases AIDS unit.

This kind of intensive monitoring - and the fact that PrEP has only been tested in high-risk groups - would limit the ability to task shift provision away from the country's scarce doctors and confine initial use to high-risk populations such as MSM, commercial sex workers and HIV-negative partners in discordant couples, suggested Rees.

Fears about drug resistance in the 1990s delayed the national provision of single dose nevirapine PMTCT. It was eventually rolled out after the Treatment Action Campaign won a court case against the government. While the single-dose regimen did lead to some drug resistance in both mothers and infants, Rees said too many lives were lost to delays in its implementation.

Start the debate

Key to keeping the PrEP debate off court rolls would be starting a public discussion about the technology now, said Yogan Pillay, deputy director of strategic health programmes for South Africa's national health department, who spoke at the debate in his personal capacity. 

"Should we wait for the courts to make a decision given that PrEP is not 100% effective, or should we initiate a complex, public debate around the pros and cons of this new technology and get a social compact between policy-makers, researchers and the makers of new technologies as well as communities?

"My sense is that through the institutions we have developed, like the South African National Aids Council, we should start these discussions even before the technology progresses and if we don't we'll lose a valuable opportunity."

Private sector may be first out of the gate

While Pillay stressed that it was too early for the government to adopt a formal position on PrEP, Morris said this might not stop an informal private sector roll-out.

"After the publication of the iPrEx results, a doctor is perfectly justified in prescribing tenofovir to a high-risk [HIV-negative] gay man in his office and I'm sure that is going to happen," she told IRIN/PlusNews.

Jonathan Berger, a researcher with the human rights organization Section27, said that without public sector provision, socio-economics would largely determine who would benefit.

"This is going to become an access issue because for those in the private sector with money, they'll be able to get access - those in the public sector will have to wait for the policies to be implemented," he added. "It's really going to become a question of the haves and the have-nots. For me, it's not really a question of whether we implement but when and how."

Further research raises ethical questions

While the development of national policies hinges on more research, both Rees and Morris agreed that this was becoming increasingly difficult and ethically questionable.

Clinical studies must be approved by ethics boards, which require that trials offer effective prevention packages to participants, whether they receive the test drug or a placebo. The high levels of efficacy found by PrEP studies such as iPrEx and CAPRISA may mean it is no longer ethical to leave PrEP out of these kinds of packages.

"As we get new [proven] technologies, we are morally, ethically and clinically bound to offer this to people who participate in these studies; if we have men participating in vaccine studies now, you have to offer them circumcision," Rees told IRIN/PlusNews.

According to Morris, the US Food and Drug Association is pushing for a follow-up study to confirm the almost 40% reduction in HIV infections found in the CAPRISA study but with such good results, she sees huge ethical issues in conducting a repeat study in which not all participants were offered access to the gel.

Finding a way to eventually put research into practice was not only necessary but also a moral obligation, Rees noted.

"I'd ask why we're doing these studies in these countries at all if we're not going to implement any of these interventions," Rees said. "I find that unethical." - (PlusNews/IRIN, November 2010)


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Dr Sindisiwe van Zyl qualified at the University of Pretoria before working for an HIV/AIDS NPO in Soweto for many years. She was named one of the Mail & Guardian's Top 200 Young South Africans in 2012.

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