A new treatment for HIV positive people who have built up a resistance to other drugs has become available for use in the UK>

Raltegravir is the first in a new class of HIV treatments called integrase inhibitors.

It is available in tablet form and has been approved for use in combination with other antiretroviral drugs to treat HIV infection in adult patients whose current therapy is no longer controlling the virus.

Patients with HIV are increasingly showing resistance to medication.

The BBC reports that more than one in 10 UK patients with HIV has some level of resistance to at least one drug before they have even begun therapy.

This is because the virus mutates and new strains become immune to existing drugs.

It is estimated that 73,000 people in the UK are living with HIV.

One in three people do not know they are infected.

2,700 gay and bisexual men were newly diagnosed last year, the highest number ever.

Across the UK 1 in 20 gay and bisexual men are now living with HIV and estimates suggest this figure is as high as 1 in 10 in London.

If rates continue the National AIDS Trust says that by 2010 there will be 100,000 people living with HIV in the UK.

Roger Pebody, treatment advisor at the Terrence Higgins Trust, told the BBC:

“This is excellent news for people who are resistant to other HIV drugs.

“A combination of drugs is used to stop HIV at different stages of the process of entering and destroying the body’s immune cells.

“If someone becomes resistant to any of their drugs, their treatment needs to be changed, and drugs which work in innovative ways can make a real difference.”

Two recent studies on Raltegravir examined its tolerability and efficacy, its ability to reduce viral load and raise CD4 cell count in treatment-experienced, triple class resistant patients living with HIV, a difficult to treat patient population.

24 week outcomes of the pooled studies have shown that 75 percent of patients receiving Raltegravir plus Optimised Background Therapy (OBT – a regime of active antiretroviral drugs tailored to individual patients, chosen by their physicians as most likely to be of benefit) achieved HIV viral load reduction to less than 400 copies/ml at 24 weeks compared to 40 percent taking placebo plus OBT.

In the same studies, it was shown that 63 percent of patients receiving Raltegravir plus OBT achieved HIV viral load reduction to less than 50 copies/ml at 24 weeks compared to 34 percent taking placebo plus OBT.

The studies also found the increases in CD4 cell counts from baseline were 84 cells/mm3 for patients receiving Raltegravir compared with 37 cells/mm3 for those receiving placebo.

An analysis of the same trials at 16 weeks showed that after 16 weeks of treatment, ‘Isentress’ plus OBT was generally well-tolerated.

The most commonly reported therapy-related side effects, as reported in at least three per cent of patients, were diarrhoea, nausea, abdominal distension, abdominal pain, flatulence, headache and fatigue.