US investigators have found evidence of the "remarkable" success of antiretroviral therapy in disadvantaged urban minority populations. In the online edition of Clinical Infectious Diseases, researchers from Johns Hopkins’ University, Baltimore, report that in 2010 their patients’ average viral load was below 200 copies/ml.

"This is a remarkable accomplishment that is probably due to improved antiretroviral drugs and changes in management, including the starting of therapy at less advanced immunosuppression," comment the authors.

They add that the levels of HIV suppression achieved by their patients could have important implications for the prevention of further HIV transmissions.

Triple-drug antiretroviral therapy first became available in 1995-96. However, it was based on unboosted protease inhibitors that lacked potency. Treatment also had other limitations. It often involved unpleasant side-effects, adherence was difficult, and many patients had pre-existing resistance due to a history of previous therapy involving only one or two anti-HIV drugs.

Since then there have been major improvements in HIV treatment and care. These have included the introduction of boosted protease inhibitors and potent NNRTIs, as well as the development of drugs in new classes. Indeed, the goal for HIV treatment for most patients is an undetectable viral load. Moreover, there have also been changes in treatment guidelines, which now recommend the early initiation of antiretroviral therapy.

Johns Hopkins’ HIV clinic serves a large socially disadvantaged urban population. Between 1996 and 1998 only 44% of the clinic’s patients taking HIV therapy achieved an undetectable viral load, but by 2001 to 2002 this had increased to 79%.

Investigators from the clinic wanted to see how changes in HIV treatment and care had impacted on their patients’ viral load between 1996 and 2010.

A total of 5290 individuals were included in the investigators’ analysis.

There were important changes in the demographics and clinical characteristics of the patients over the period of the study.

Their median age increased from 38 years in 1996 to 49 years in 2010. There was also a marked fall in the proportion of patients who were infected with HIV via injecting drug use, from 46% in 1996 to 36% in 2010. At the same time, there was an increase in the percentage of patients who acquired HIV through heterosexual intercourse (43% to 51%).

The proportion of patients taking triple-drug antiretroviral therapy increased from 22% in 1996 to 85% in 2010, and overall CD4 cell count increased from a median of 239 cells/mm³ to 444 cells/mm³.

Median viral load fell from 10,000 copies/ml in 1996 to below 200 copies/ml in 2010. Moreover, by 2010, only 17% of patients had a viral load above 500 copies/ml.

Rates of retention in care improved from 86% in the period 1996 to 2002 to 94% by 2010.

"We believe that our results emphasize that even an inner urban HIV-infected population with a relatively high proportion of patients who were infected as a consequence of injecting drug use, HAART [highly active antiretroviral therapy] can be highly efficacious," write the authors.

They add: "These results…reflect the increasing use of HAART and are a testament to the remarkable effectiveness of HAART in our patient population."

There is considerable interest in the use of HIV treatment as prevention, and the investigators believe that the viral suppression achieved by their patients "may…have implications for transmission of HIV in the urban community which the Johns Hopkins HIV clinic draws its patients."

An editorial accompanying the study is equally enthusiastic about its findings, the author commenting, "the results of the study are highly relevant for clinicians, because they show an extremely high treatment success rates, even in the context of challenging sociodemographic circumstances. Providers faced with potentially difficult cases can be reassured that most of these cases are in patients who will achieve virologic suppression with the effective and well-tolerated regimens now available."

Moore RD et al. Dramatic decline in the HIV-1 RNA level over calendar time in a large urban HIV practice. Clin Infect Dis, online edition: doi: 10.1093/2011/536-0017, 2011 (click here for the free abstract).

Sax PE. Antiretroviral therapy: now "it just works." Clin Infect Dis, online edition, doi: 10.1093/2011/536-0018, 2011 (click here for the free extract).