Antiviral effect of double and triple drug combinations amongst HIV-infected adults: lessons from the implementation of viral load-driven antiretroviral therapy

Objective: To study the antiviral effect and predictors of response to two-and three-drug regimens amongst antiretroviral-naive individuals using an intent-to-treat analysis. Main outcome measure: Suppression of plasma viral load to <500 copies/ml. Patients: A total of 420 (264 double drug, 156 triple drug) individuals in a province-wide treatment programme were studied. Results: A decrease in plasma viral load to <500 copies/ml was documented in 197 (47%) subjects. This was independently associated with a lower baseline plasma viral load (odds ratio, 3.67; 95% confidence interval, 2.13-6.30) and initiation onto a three-drug regimen (odds ratio, 3.86; 95% confidence interval, 2.24-6.66). Median plasma viral load failed to reach <500 copies/ml and in fact rebounded in the two-drug group. In contrast, 91 (58%) subjects receiving three drugs reached <500 copies/ml during the study period. Conclusion: These results support the use of powerful triple drug regimens as initial therapy in HIV-infected individuals.