Reuters 24 July 2000

Westport -- Triple therapy for HIV-infected patients, including regimens containing a protease inhibitor, do not have any unique effects on CD4 cell counts independent of reductions in plasma viral load, according to findings reported in the July issue of AIDS.

The data appear to contrast with recent evidence suggesting that such regimens are able to maintain an immunologic benefit even after plasma viral rebound, Dr R. Harrigan, of St Paul's Hospital in Vancouver, British Columbia, and other investigators for the AVANTI and INCAS studies explain.

The team examined the correlation between CD4 cell counts and plasma viral load over 52 weeks using data from 3 randomized clinical trials: AVANTI-2, AVANTI-3, and INCAS. The studies compared dual nucleoside therapy with triple combination therapy that included a protease inhibitor, with or without a nonnucleoside reverse transcriptase inhibitor.

"The data presented in these randomized double-blinded trials suggest that the specific antiretroviral regimen used neither increases nor decreases the strength of the correlation between the change in CD4 cell count and the change in plasma viral load," Dr Harrigan and colleagues say. The strength of the correlation was similar among all groups of patients in the studies, regardless of the type of treatment they received.

Discordant increases or decreases in plasma load and CD4 cell counts did occur in some patients, but they were not linked to any particular therapeutic regimen and were regarded as "natural variation" by the authors.

"The data provide no evidence for a CD4 cell count benefit unique to protease inhibitors," the investigators conclude, "at least in first-line regimens up to 1 year in patients with moderate baseline CD4 cell count."

AIDS. 2000;14:1383-1388.