HIV Weekly - 13th July 2011

Breaking news!

This is a revised version of this week's HIV Weekly, to incorporate exciting news from two important trials (see below).

HIV treatment – PrEP works

Initial findings were released today from two large studies showing that pre-exposure prophylaxis can cut the risk of HIV infection by up to 73% in heterosexual couples.

Pre-exposure prophylaxis (PrEP) involves people who are HIV-negative taking anti-HIV drugs to prevent HIV infection.

The Partners study, which took place in Kenya and Uganda, gave participants either tenofovir (Viread), Truvada (tenofovir and FTC) or a placebo. Infections were reduced by 62% in people taking tenofovir alone and by 73% in those taking Truvada. The study was ended more than 18 months early because early results showed PrEP was so effective.

Participants in the TDF2 study, in Botswana, took either Truvada or a placebo; Truvada reduced infections by 63%.

Co-chair of the Partners study, Dr Jared Baeten, says: “This is a very exciting finding for the field of HIV prevention. Now … the priority for HIV prevention research must be on how to deliver successful prevention strategies, like PrEP, to populations in greatest need.”

These findings add to the picture of effectiveness of PrEP, following recent conflicting findings from the iPrEX study and the FEM-PrEP trial.

More detailed findings from the TDF2 study will be presented at the IAS conference in Rome next week, and NAM will report on these in our daily bulletins from the conference (see box to the right). You can also visit our online ‘Pre-exposure prophylaxis’ resource for more discussion and information on previous research.

HIV and cancer

Some types of cancer are more common in people with HIV than in the general population. Some of these cancers are considered AIDS-defining illnesses, such as Kaposi's sarcoma (KS), non-Hodgkin's lymphoma (NHL) and cervical cancer.

A recent study has found that people whose immune system is badly damaged are at greater risk of developing AIDS-defining cancers, not only before starting treatment but also in the first three months after starting.

Researchers confirmed that people whose CD4 count was low in the year before starting treatment were at increased risk of these cancers, and also noted that CD4 counts fell faster in people who went on to develop AIDS-defining cancers.

The study also found there was an increased risk of developing cancer (especially Kaposi’s sarcoma or non-Hodgkin’s lymphoma) in the first three months after starting treatment. Researchers link this to a condition called immune reconstitution inflammatory syndrome (IRIS). This is when someone becomes more ill on starting HIV treatment, as their immune system gets stronger and starts to fight any infections present. IRIS is more common in people whose CD4 count was low when they started treatment (under 100) or who have another illness, such as tuberculosis (TB); the symptoms of that illness may become worse.

Previous research has shown that Kaposi’s sarcoma can be linked to IRIS. The aim of this new study was to get a better understanding of the risk of developing AIDS-defining cancers after starting HIV treatment, and whether IRIS did increase the risk.

The researchers found that the risk grew in the period immediately after starting HIV treatment. Researchers believe this is because Kaposi’s sarcoma and non-Hodgkin’s lymphoma are linked to viral infections, which may become more severe if someone develops IRIS.

However, their key conclusion is that the main risk factor for AIDS-defining cancers is a damaged immune system, and that starting HIV treatment is the most effective way to reduce the risk of developing such cancers.

Other cancers are not regarded as AIDS-defining because their higher rates have not been definitely linked to a damaged immune system. However, they are often still more common among people with HIV. These include Hodgkin's disease, anal cancer and lung cancer. A key risk factor for some of these cancers is smoking, which can also cause heart disease and other health problems. Stopping smoking (or not starting in the first place) will significantly reduce your risk of developing these conditions.

If you want to give up smoking, talk to your doctor or another member of your healthcare team about the support available to you. In the UK, most NHS trusts offer support with stopping smoking. You can call the NHS Stop Smoking Helpline on 0800 022 4 332 or visit the NHS website www.smokefree.nhs.uk.

HIV treatment – abacavir as effective as tenofovir

Researchers have found that, among patients receiving routine treatment in Canada, the treatment combination of abacavir (Ziagen) with 3TC (lamivudine, Epivir) is as effective as the combination of tenofovir (Viread) with FTC.

Tenofovir and FTC are commonly prescribed as a combination pill called Truvada, and are also combined with efavirenz in the triple-drug pill Atripla. Abacavir and 3TC are combined in one pill called Kivexa.

Previously, there has been discussion as to whether HIV treatment containing abacavir is as effective as tenofovir. Early results of one study suggested that people on abacavir had to change treatment because their viral load became detectable earlier than people on tenofovir. However, final results from the ACTG 5202 study showed there was no significant difference in people with viral loads below 100,000 copies/ml.

Now, this new study has shown that there is no difference in the risk of treatment failure for people with viral loads over 100,000 copies/ml.

There have also been concerns about the side-effects of abacavir, with some research studies showing a link with heart attack. However, other studies have not found this connection.

Abacavir is now prescribed as the recommended first-line NRTI treatment for people in London.

HIV and children – managing the risk of heart disease

It’s now well established that people with HIV have an increased risk of cardiovascular disease (CVD).

There a lot of debate about the causes, but the most important seem to be the damage caused by untreated HIV infection, and traditional risk factors such as smoking. Some studies have shown that treatment with some anti-HIV drugs increases the risk of heart disease.

Now, a US study has found that children with HIV who developed high cholesterol (or lipid levels, a risk factor for cardiovascular disease) still had high cholesterol when followed up two years later.

Controlling cholesterol levels in children is important as they are likely to spend many years on HIV treatment. The researchers are concerned that there is no standard guidance on how cholesterol levels are managed in children with HIV. They recommend that formal guidelines be developed, taking a combined approach to managing cholesterol levels (and CVD risk) including ‘lipid-friendly’ anti-HIV drugs, lifestyle changes and the use of statins (lipid-lowering drugs).

Routine HIV care involves regular tests to monitor cardiovascular health, meaning that problems can be spotted early and appropriate action taken.

There’s also a lot you can do to look after your heart – for example not smoking, eating a healthy diet, and exercising regularly – help and advice about all these is available from your HIV clinic or GP.