RESUMEN
OBJECTIVES: To determine etravirine concentrations and the HIV-1 viral load (VL) in blood plasma (BP) and seminal plasma (SP) of HIV-infected patients. METHODS: Ten adult antiretroviral-experienced HIV-1 patients receiving an etravirine-containing regimen for at least 1 month were enrolled. Semen and blood samples were collected ~12 or 24 h after the last etravirine dose, depending on twice-daily or once-daily dosing, respectively. Liquid chromatography tandem mass spectrometry was used to determine etravirine concentrations and HIV-1 VL was determined by real-time PCR (detection limit 40 copies/mL). Results are presented as the median (range) unless otherwise indicated. RESULTS: Ten blood and 20 semen samples were collected. The CD4 count was 502 (252-817) cells/mm(3) and the BP VL was <40 (<40-362) copies/mL. The time on etravirine was 52 (12-124) weeks. The BP etravirine concentration was 452.5 (258-751) ng/mL. The SP etravirine concentration was 62.9 (31.2-166.0) ng/mL and values were above the IC(50) range (0.39-2.4 ng/mL) in all cases. The median etravirine SP:BP ratio was 0.16 (0.07-0.26). The SP VL was <40 copies/mL in all patients, whereas the BP VL was detectable in one patient with poor adherence to treatment. CONCLUSIONS: Etravirine concentrations in male genital secretions are modest, reaching only 16% of the BP concentration. Nevertheless, they are more than 10 times greater than the wild-type IC(50) range (not adjusted for protein binding).