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This is our final news bulletin from the 6^th International AIDS Society conference in Rome. You can find all our coverage on our website at www.aidsmap.com/ias2011. 

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The use of HIV treatment as prevention was the major theme of the conference, but some important research on new approaches to HIV treatment was also presented.

Overall, the conference was characterised by excitement and optimism – and there was even talk about the science that could lead to a cure.

Nevertheless, delegates were left with no illusions about the continuing seriousness of the epidemic, and the formidable challenges that stand in the way of realising the potential of treatment as prevention.

Perhaps the greatest hurdles are the high number of undiagnosed infections, the large number of people in HIV care who are not yet on HIV treatment, and the need for greater global financial commitment to ending the epidemic.

Dr Audrey Pettifor of the University of North Carolina. ©IAS/Moreno Maggi

About a quarter of all HIV infections in the US are undiagnosed and only 19% of people with HIV have an undetectable viral load. This seriously limits the potential of HIV treatment to have a real impact on the rate of new infections.

One radical approach to boosting testing and adherence is to offer cash or other financial incentives.

The incentive approach is not without its critics. Some believe that it fails to address the societal problems that lead to the spread of HIV; others say it is a form of social engineering.

A conference symposium on the subject explored several approaches.

Researchers in San Francisco found that giving a cash incentive increased hepatitis B vaccination rates among injecting drug users.

In one trial in the US, cash incentives are being offered to people who test HIV-positive to encourage them to access treatment and care services within three months of their diagnosis. A cash reward is also provided if a patient achieves and maintains an undetectable viral load.

In a number of programmes in sub-Saharan Africa, cash incentives are being offered to people who remain free of HIV and other sexually transmitted infections.

Robert Grant, iPrEx study lead investigator. ©IAS/Marcus Rose/Worker's Photos

Closer analysis of the results of the iPrEX study of pre-exposure prophylaxis (PrEP) use by gay men has yielded mixed findings.

Men in the study were randomised to receive FTC/tenofovir (Truvada) PrEP or a placebo.

When results of the study were first announced last November, they showed that taking PrEP reduced the rate of HIV infections by 44%.

A re-analysis of the results has shown that efficacy was slightly lower – only 42%.

However, there was good evidence that PrEP was highly effective if men took the treatment consistently.

The rate of infections was reduced by 92% for men who had detectable levels of anti-HIV drugs in their blood.

Presenter Charles van der Horst, University of North Carolina. ©IAS/Marcus Rose/Worker's Photos

HIV treatment is routinely used to reduce the risk of mother-to-child transmission of HIV.

Rates of transmission can be reduced to less than 1% by the use of HIV therapy, having an appropriately managed delivery, and not breastfeeding.

However, the avoidance of breastfeeding is not an option for some women, especially if they are in a country where there isn’t a safe alternative.

Several studies have shown that extended infant prophylaxis with nevirapine, or with nevirapine and AZT, during breastfeeding reduces the risk of transmission.

Now a pooled analysis of those studies has shown that extended infant prophylaxis during breastfeeding, using AZT and nevirapine, reduced the risk of mother-to-child transmission by 71%.

“Extended prophylaxis with nevirapine or with nevirapine and zidovudine significantly reduces postnatal HIV-infection; the longer the duration of prophylaxis, the greater the reduction in the risk of infection,” said one of the researchers.

The prevention of unwanted or unplanned pregnancy is one of the pillars of programmes to prevent mother-to-child transmission, but research presented at the conference showed a huge unmet need for family planning advice among couples where one or both partners has HIV.

Few couples employ dual-protection methods (using condoms alongside another contraceptive method), while there is low awareness of strategies which allow a serodiscordant couples to conceive while limiting the risk of sexual HIV transmission.

Dr Alison Roxby of University of Washington, Department of Medicine, Seattle. Image by Theo Smart (aidsmap.com)

Several studies presented at the conference showed that two drugs developed to treat herpes simplex virus (the cause of genital herpes) slow down the rate of disease progression in people with HIV.

Aciclovir and valaciclovir have both been tested as treatments to prevent HIV transmission, without success. Aciclovir reduced the risk of CD4 cell decline in a Ugandan trial, while a randomised study of valaciclovir in pregnant and breastfeeding women showed that women who received valaciclovir had increases in CD4 count and reductions in viral load that lasted at least one year. The researchers said that valaciclovir might delay the need for antiretroviral treatment by nearly two years, and could represent a cost-effective option in low-income settings where antiretroviral treatment is not yet affordable for all pregnant women.

This study also found that valaciclovir reduced levels of HIV in breast milk, suggesting that it could reduce the risk of passing on HIV during breastfeeding. Another study showed that valaciclovir had a much greater effect on viral load in the blood than aciclovir.

With the right treatment and care many people with HIV now have a near-normal life expectancy.

But like all medicines, the drugs used to treat HIV can cause side-effects. Doctors are especially concerned that treatment with some drugs may increase the risk of diseases normally associated with ageing – for example bone problems and cardiovascular disease.

The class of anti-HIV drug most associated with longer-term side-effects is the nucleoside reverse transcriptase inhibitor (NRTI) group. These drugs form the backbone of nearly all HIV treatment combinations.

Research presented to the Rome conference suggests that it may be possible to construct a safe and effective combination that doesn’t include NRTIs.

One study showed that treatment with the integrase inhibitor raltegravir (Isentress) and ritonavir-boosted darunavir (Prezista) was as effective as a more traditional HIV treatment combination of Truvada and ritonavir/darunavir.

The study involved people who were starting HIV treatment. After six months, equal proportions of patients had an undetectable viral load, and CD4 cell increases were also comparable.

A second study looked at the safety and effectiveness of a combination that included the CCR5 inhibitor maraviroc (Celsentri) with ritonavir-boosted atazanavir (Reyataz). Once again the combination was compared to a regimen based on Truvada.

Six-month results had shown the two combinations to be equally effective.

However, after a year there was a small drop in the proportion of patients taking the NRTI-sparing combination who had an undetectable viral load. In comparison, the number of patients taking the NRTI-containing combination with undetectable viral load remained steady.

Nevertheless, the level of viral rebound was low, and all patients eventually re-suppressed to undetectable levels without a treatment change.

Images from presentation by Jan van Lunzen from University Medical Center in Hamburg-Eppendorf

Integrase inhibitors are a new class of HIV drug. They prevent HIV‘s genetic material being integrated into human cells, and seem potent and very well tolerated.

New data on an integrase inhibitor being developed by ViiV Healthcare, called dolutegravir, were presented in Rome. It will be the first once-daily integrase inhibitor that will not require a boosting agent. Compared to standard-of-care treatment containing efavirenz, treatment with dolutegravir was just as potent, but with fewer side-effects.

Dolutegravir is being tested in phase 3 trials with a view to licensing in 2013, and a fixed-dose combination pill that also contains abacavir and 3TC is planned.