Background: The treatment of HIV-1-infected patients with triple-drug combination therapy results in profound suppression of viral replication. In most therapy-naive patients plasma HIV-1-RNA levels (pVL) drop below the lower limit of quantification (LLQ) of currently used assays. In a large percentage of such patients, more sensitive assays provide evidence of residual viral replication. The question is whether more potent therapy can further suppress this residual replication.
Methods: Thirty control patients who, using very strict criteria, had not experienced virological failure during 3 years of standard therapy, were compared with 10 patients treated with a five-drug regimen, consisting of three different classes of antiretroviral drugs (alternative multidrug regimen). A modified ultrasensitive assay with an LLQ of 5 copies/ml was used to re-test plasma obtained at week 48 and at three timepoints at and around week 144.
Results: At weeks 48 and 144 pVL could be quantified significantly more frequently in control patients than in patients using the alternative multidrug regimen (week 48: 42 versus 0% with quantifiable pVL, P = 0.017; week 144: 60 versus 14% with at least one quantifiable pVL, P = 0.036, respectively). A low baseline CD4T cell count was predictive of quantifiable pVL in control patients, but not in alternative multidrug patients.
Conclusion: This proof-of-principle study demonstrates that the use of an alternative multidrug regimen results in stronger long-term suppression of pVL compared with clinically successful treatment with standard therapy.