A COMMON SITUATION: Among HIV-infected patients treated with antiretroviral regimens, 20% to 50% escape therapeutic control. The principal factors predictive of treatment failure are low CD4 counts and high viral load prior to institution of the antiretroviral treatment. Several virological and pharmacological mechanisms are implicated.
Genotyping and phenotyping: Genotyping is particularly useful to optimize treatment in HIV-infected patients who escape therapeutic control, irrespective of the therapeutic strategy. A committee of experts has developed a scheme for adapting treatment to the very complex results of genotyping tests. The benefit of phenotyping remains to be established.
Management: Serum concentrations of antiretroviral agents should be determined and adapted in order to maximize the treatment effect. However, to manage therapeutic escape, the only method with a proven impact is genotyping. The possible usefulness of regular drug assays for adjusting treatment doses in case of therapeutic escape remains to be assessed in prospective trials.