Abstract
Darunavir/ritonavir monotherapy maintains HIV suppression in most patients who have achieved an undetectable viral load on combination antiretroviral treatment, and is increasingly used in the clinic. However, concerns have been raised about the effectiveness of ritonavir-boosted protease inhibitor (PI/r) monotherapy in the prevention of HIV replication in the central nervous system (CNS). Here we report the cases of 2 patients on darunavir/r maintenance monotherapy with cerebrospinal fluid viral breakthrough together with increased immunoactivation and biomarker signs of neuronal injury. These 2 cases raise concerns about the effectiveness of darunavir/ritonavir monotherapy in HIV CNS infection. Thus, we recommend caution with protease inhibitor monotherapy until CNS results have been obtained from clinical studies.