Low Trough Plasma Concentrations of Nevirapine Associated with Virologic Rebounds in HIV-Infected Patients Who Switched from Protease Inhibitors

BACKGROUND:The substitution of a nonnucleoside reverse-transcriptase inhibitor (NNRTI) for protease inhibitors (PIs) has demonstrated its suitability to maintain virologic response. However, the switch from PIs to an NNRTI could fail for a number of reasons, including NNRTI-associated toxicity and emergence of NNRTI-resistant variants.OBJECTIVE:To describe the virologic failures among 74 HIV-infected patients who switched from PIs to nevirapine.METHODS:Virologic failure was defined as any rebound of the plasma HIV-RNA (pVL) levels >1000 copies/mL on one occasion or 2 consecutive intermittent viremia episodes defined as increases of the pVL >20 copies/mL but <1000 copies/mL. Virolog…