HIV-infected people can have an increase in inflammation in their body organs, even after taking anti-HIV medicines. Inflammation is a normal body reaction to any infection. However, if inflammation lasts a long time like in HIV infection, it may lead to complications, such as heart disease, cancer, liver disease, and problems with thinking. Also, HIV-infected people with high inflammation have lower CD4+ T-cell counts (cells that fight infection). Many HIV researchers are studying the harmful effects of this prolonged inflammation and possible ways to prevent these complications.

The increase in inflammation in HIV-infected people may be caused by HIV or by other factors such as parts of bacteria. These bacterial pieces, called endotoxins, do not cause harm in the intestine (gut). However, in HIV infection, there is damage to the gut that allows endotoxins to cross from the gut into the blood. These endotoxins then cause inflammation in the body. New research is focusing on strategies to reduce the levels of endotoxin as a way to decrease inflammation.

A drug called sevelamer carbonate is used to bind phosphate in dialysis patients. However, sevelamer carbonate also binds endotoxin in the gut and lowers endotoxin levels in the blood of dialysis patients. Sevelamer carbonate also decreases the inflammation endotoxin causes in dialysis patients. This study will see if sevelamer carbonate can have the same effects in HIV-infected patients.

A5296 is a phase II, single-arm study to evaluate the effect of 8 weeks of sevelamer carbonate administration on markers of microbial translocation as well as monocyte and T-cell activation in the blood in chronically HIV-infected subjects with CD4+ T-cell count ≥ 400 cells/mm3 not receiving ART. This study enrolled 40 subjects. To assess whether there is a persistent effect of study drug, subjects were observed for an additional 8 weeks off sevelamer carbonate and changes in biomarkers were monitored.

As A5296 is a phase II study of biologic activity, the primary and secondary analyses are as-treated, limited to subjects who have data for baseline and week 8 and who remain on study treatment through week 8. For any subject who initiated antiretroviral treatment (ART), analyses only included data collected prior to the time ART was started.