Comparative potency of three antiretroviral therapy regimes in primary HIV infection.

Background: Virally mediated destruction of HIV-specific CD4+ T-cells in primary HIV infection (PHI) may be abrogated by potent antiretroviral therapy (ART) started in acute infection. To best achieve the most rapid reduction in primary viraemia we compared three different ART regimens in PHI.

Study Design And Methods: A sequential, unblinded, non-randomized prospective cohort study. The primary endpoint was time to achieve plasma viral load (pVL) < 50 copies HIV RNA/ml. One hundred and five patients identified with PHI according to the definition: HIV antibody negative with positive HIV DNA (n = 22), HIV antibody positive with a documented negative test within the previous 6 months (n = 53), low-level incident 'detuned' assay (n = 10) or an evolving HIV-antibody test (n = 20) were recruited. Ninety of 105 individuals chose to take a short course of ART at PHI whereas 15 of 105 declined therapy. Seventy-nine of 90 were included for analysis and were allocated sequentially to either three (29 of 79) or four-drug (33 of 79) or protease inhibitor-containing ART (17 of 79).

Results: A mathematical model-based analysis of viral decay indicated significantly faster viral load decline in patients receiving the four-drug regimen (P = 0.01). This conclusion was supported by a non-significant on-treatment analysis of the time taken to reach pVL <50 copies HIV RNA/ml (P = 0.07) but not by the corresponding intend-to-treat analysis. This discordance was caused by greater toxicities associated with the four-drug regimen, although the differences were not significant.

Conclusion: Of the three treatment regimens compared, the four-drug arm enhanced the rate of decline of primary viraemia but at the cost of toxicity.