According to an investigation published Online First in The Lancet Infectious Diseases, there has been a significant improvement in the past ten years in western Europe, in the ability of antiretroviral therapy (ART) to suppress and stop the progression of HIV in individuals with virological failure to the three original antiretroviral drug classes, as well as reduction in the rates of AIDS. The researchers claim that this effect is most likely due to many novel medications being easier to use, more tolerable and active against virus resistant to usual first-line and second-line medications, and being introduced over the same period.

Starting in 1998, it has been recommended that all patients start ART with three or more medications from two or more different classes so that viral load (the amount of virus in the blood) can be considerably reduced, as well as to suppress the development of resistance to drugs and HIV replication. Although, until recently, those who developed resistance to the medications from each of the three original classes, known as triple-class virological failure (TCVF), had very few treatment options available.

In order to evaluate if the outcomes for those with TCVF have improved in the past decade, researchers from the Pursuing Later Treatment Option II (PLATO II) project, examined data from the COHERE database (a combination of 33 observational investigations of HIV in Europe). The examination included 91,764 adult individuals, out of which 2,476 experienced triple-class virological failure.

The researchers used modelling in order evaluated trends in virological suppression (a viral load under 500 copies per ml) after taking in to account factors that may affect the chances of virological response including mode of transmission, age, sex, CD4 count and presence of AIDS. They also calculated the prevalence of AIDS or death after TCVF.

In 2000, nearly 1 in 5 patients achieved undetectable levels of HIV (a viral load under 50 copies per mL), this has risen considerably to almost 3 in 5 in 2009. They highlight that between 2008 and 2009, shortly after four novel medications were approved in Europe, the trend for improved virological outcomes was strongest.

The prevalence of any AIDS event declined from 7.7 per 100 individuals between the years 2000 and 2002, to 2.3 per 100 in 2008, and 1.2 per 100 in 2009. The researchers explain: “Whether the improving trend, or even the current rate of viral suppression in 2009, can be sustained in the future is unclear. Continued improvement will likely need continued development of new drugs, which are active against virus with resistance to existing drugs.”

Jens Lundgren from Copenhagen University Hospital and Jeff Lazarus from Copenhagen University, Copenhagen, Denmark comments:

“The results presented by the PLATO II collaboration should not lead to complacency. The number of people with resistance to HIV infection will increase as the number of people receiving ART increases. Of particular worry is that the pace of clinical programs of HIV-drug development has slowed down in the past couple of years.”

The researchers also highlight the need to access alternative, more affordable, and less toxic drugs in sub-Saharan Africa and Eastern Europe. “As access to ART is scaled up, a sizable proportion of people living with HIV in these regions will live for extended periods on virologically failing ART. This scenario allows for renewed progression of their HIV condition and the transmission of resistant HIV to others. Recognition of the problem and innovation to addressing it are vital to the response.”

Written by Grace Rattue