Health

MAURA ELARIPE was diagnosed with HIV in 1997, aged 21. In 2002, she started standard triple therapy, which saved her life. But two weeks ago, Elaripe discovered that she is no longer responding to treatment.

Elaripe lives in Papua New Guinea, but the problem of drug-resistant HIV is not confined to developing countries. In the US alone, an estimated 25,000 to 40,000 patients are now resistant to many HIV drugs.

But there is good news. Later this year, two new classes of drugs are expected to secure approval and be added to the HIV arsenal. The first are entry inhibitors, designed to stop HIV invading healthy T-cells by targeting either proteins on the surface of HIV or on the T-cells they infect. Last month, the European Medicines Agency recommended approving Pfizer's entry inhibitor Celsentri, and the European Commission is expected to make a final decision by the end of September. The US Food and Drug Administration (FDA) is also considering giving it the go-ahead.

At the annual meeting of the International Aids Society (IAS) in Sydney, Australia, last week, Roy Gulick of the Weill Cornell Medical College, New York, and colleagues presented promising results on Schering-Plough's entry inhibitor, vicriviroc, a potent suppressor of viral replication in drug-resistant patients.

The second class of drugs targets integrase, one of three enzymes HIV needs to insert its DNA into the genome of T-cells. It looks like Merck's raltegravir will be the first to receive FDA approval in September. Back in April, raltegravir was shown to reduce HIV levels in patients who were not responding to other treatments (The Lancet, DOI: 10.1016/S0140-6736(07)60597-2).

It also seems to be unusually effective at reducing viral load during later phases of therapy, unlike other drug combos that cause a big initial drop in virus levels, followed by less dramatic reductions, says John Murray of the National Centre in HIV Epidemiology and Clinical Research in Sydney, Australia, who also presented results at the IAS. It's not yet known why this should be so, but raltegravir could open up new ways of targeting different stages of HIV's life cycle, Murray says.

The new drugs appear to reduce HIV to below detectable levels in about 60 per cent of drug-resistant patients who are receiving integrase and entry inhibitors ahead of approval, on compassionate grounds.

However, we still haven't come close to truly eradicating the virus in anyone, warns Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases in Bethesda, Maryland. As for Elaripe, she welcomes the new treatments - for those who can get hold of them. For herself, she says she is scared about the future. "But I am always hoping one day there will be a cure."

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