Monotherapy in treatment-naïve patients

The development of antiretroviral therapy (ART) with current triple drug combinations has dramatically reduced morbidity and mortality in HIV-infected patients. However, there is a need for less toxic treatments without sacrificing efficacy, as well as for less expensive drugs to facilitate universal access to this therapy. The protease inhibitors (PI) administered with ritonavir have a favorable pharmacokinetic profile and high genetic barrier and consequently are ideal candidates for use in monotherapy, thus avoiding the toxicity and cost associated with nucleoside analogs, as well as preserving drugs for future options. The promising results of studies performed with lopinavir/ritonavir (LPV/r) in induction-maintenance regimens in patients without prior failure to PIs encourage research into the cost-effectiveness of LPV/r in monotherapy from the beginning of ART. The few studies performed in this context seem to indicate the following: a) LPV/r monotherapy achieves undetectable viral loads in a large proportion of treatment-naïve patients, b) future treatment options are not compromised in patients not achieving undetectable viral loads since the likelihood of resistance mutations is low and treatment intensification achieves suppression of viral replication, and c) strategies for early detection can probably be considered in patients who will not achieve complete suppression with LPV/r monotherapy. Nevertheless, before LPV/r monotherapy can be considered a first-line option, new studies with larger samples and longer follow-up are required. These studies should pay particular attention to viral replication in areas where PI show less penetration.