January 15, 2013
Viral load reduction, no matter how small, can have immunological benefits for people living with HIV who have experienced triple-class treatment failure, according to a recent study from the Collaboration of Observational HIV Epidemiological Research Europe (COHERE).
Despite the various antiretroviral classes currently available for people living with HIV, many individuals still develop drug resistance, which leads to fewer options. Often, for patients with multi-class resistance, clinicians take actions with the primary goal of increasing CD4+ cell count (in order to reduce the risk of serious illness), rather than take actions with the primary goal of suppressing HIV viral load.
To explore the wisdom of this approach, researchers analyzed viral load data on 2,424 people who had started antiretroviral therapy from 1998 onward and who had experienced treatment failure with at least three classes of drugs.
In particular, they looked at treatment failure involving the three main antiretroviral classes: nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs) and ritonavir (Norvir)-boosted protease inhibitors (PI/r).
Most of the patients (67%) were men and their median age was 40 years. The patients had been taking antiretroviral therapy for a median of four years before triple-class failure was diagnosed. Median viral load at this time was 4 log10 copies/mL, whereas median CD4 cell count was 270 cells/mm3.
The investigators' initial analysis showed a strong linear association between CD4 cell count and viral load after treatment failure. CD4 cell count was 48 cells/mm3 lower per 1 log10 increase in viral load.
Only a small minority of people were treated with newer classes of antiretrovirals such as fusion inhibitors (7%), integrase inhibitors (9%) and CCR5 inhibitors (1%).
While the goal of any HIV antiretroviral regimen is to achieve an undetectable viral load, this study suggests that any degree of viral suppression can benefit a patient's CD4+ cell count and lower his or her risk of clinical disease.
"It makes sense that the lower the viral load (at least on treatment, and even with non-suppressive regimens), that the greater the benefit to CD4s (and immune function)," said Benjamin Young, M.D., Ph.D., Chief Medical Officer of the International Association of Providers in AIDS Care. (Dr. Young was not an investigator in this study.)
As for the clinical implications, the study authors concluded the following, according to aidsmap.com:
While in those with high CD4 count it may be possible to wait until new active drugs are available, for those with low CD4 count it is important to use the regimen most likely to achieve maximal viral suppression. We found that the current viral load is closely linked to the CD4 count, suggesting a rapid benefit of viral load suppression, so in an individual who is not fully adherent, any increase in adherence is likely to provide immediate benefits in terms of reduced risk of clinical disease.
Warren Tong is the research editor for TheBody.com and TheBodyPRO.com.
Follow Warren on Twitter: @WarrenAtTheBody.
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