Maraviroc potentially of benefit for many patients with late HIV diagnosis

Almost two-thirds of patients whose infection with HIV was diagnosed late had virus that uses the CCR5 co-receptor, and could therefore potentially benefit from taking a treatment regimen that includes maraviroc (Celsentri), Austrian investigators report in the 24^th August edition of AIDS.

Maraviroc was recently approved for use in first-line HIV treatment, although it is most widely used in extensively treated patients. However, the investigators believe that the drug could be especially beneficial for patients who are diagnosed late. Some research suggests that the drug can boost CD4 cell count, even when viral load is not suppressed.

HIV uses one of two co-receptors to attach to human cells: CCR5 or CXCR4. Additionally, patients may sometimes have what is called mixed or dual tropism virus, and this occurs when both co-receptors are present.

The presence of CXCR4 and dual/mixed tropism-using virus is associated with late-stage HIV disease and a low CD4 cell count.

Little is known about the re-receptor types that are present in patients whose HIV infection is diagnosed late (a CD4 cell count below 200 cells/mm³).

Therefore Austrian investigators analysed the co-receptors of 50 patients with late HIV diagnosis between 2004 and 2007. To see if any factors were associated with the presence of particular co-receptors, information was also gathered on the patients’ baseline CD4 cell count and viral, as well as their demographic details.

A total of 31 patients (62%) had HIV that used the CCR5 co-receptor.

Baseline CD4 cell counts were higher amongst patients in whom the CCR5 co-receptor was used (61 vs 32 cells/mm³), but this difference was not statistically significant. Nor was there any difference between the two groups of patients with respect to their baseline viral load.

Individuals who had been infected with HIV via injecting drug use were more likely to have virus that used the CXCR4 co-receptor or that was dual/mixed tropisms than those who were infected with HIV through sex (p = 0.02). The investigators note that earlier research has shown that CXCR4 and dual/mixed tropism virus is efficiently transmitted through injecting drug use.

Finally, the investigators restricted their analysis to patients with a CD4 cell count of 50 cells/mm³ or below at the time of their diagnosis, and compared the severity of HIV disease between those with the CCR5-using virus and those with the CXCR4 co-receptor or dual/mixed tropism virus.

Of the eleven CCR5 patients, ten had an AIDS-defining illnesses. However, only 50% of those with virus that used other co-receptors had progressed to AIDS, one patient having no symptoms of HIV disease at all.

The researchers conclude, “treatment with CCR5 antagonists in ART [antiretroviral therapy]-naive patients, even if newly diagnosed at a late stage of HIV infection, should be of value and needs further evaluation”.