Gutierrez-Valencia, AliciaTrujillo-Rodriguez, MariaFernandez-Magdaleno, TamaraEspinosa, NuriaViciana, PompeyoLópez-Cortés, Luis F2024-10-232024-10-232018http://hdl.handle.net/10668/12115https://hdl.handle.net/20.500.12105/25242Introduction: When darunavir (DRV) 800 mg is boosted with 150 mg cobicistat (DRVcobi), DRV trough concentration (Ctrough) is about 30% lower as compared to 100 mg ritonavir (DRVrtv). DRVcobi shows similar virological efficacy as DRVrtv when combined with two nucleos(t)ide analogue reverse-transcriptase inhibitors, but it is unknown whether a lower DRV Ctrough would undermine the effectiveness of DRVcobi when given as monotherapy (mtDRVcobi). Methods: Prospective observational study on virologically suppressed HIV-infected subjects who switched to mtDRVcobi . Virological failure was defined as two consecutive HIV-RNA >200 copies/mL. Efficacy was evaluated by intention-to-treat (ITT) and on-treatment (OT) analyses, and compared with data from a previous cohort of subjects on mtDRVrtv conducted at our centre. Plasma DRV Ctrough was measured using LC-MS/MS. Results: A total of 234 subjects were enrolled. At week 96, the efficacy rates were 67.8% (CI95 , 61.8 to 73.7) by ITT and 86.9% (CI95 , 78.0 to 87.7) by OT analyses. The corresponding rates in our historical DRVrtv controls were 67.6% (CI95 , 60.0 to 75.2) and 83.6% (CI95 : 77.2 to 90.0). A total of 135 DRV determinations were performed in 83 subjects throughout the follow-up period, with a median plasma DRV Ctrough of 1305 ng/mL (range, 150 to 5895) compared with 1710 ng/mL (range, 200 to 3838) in subjects on monotherapy with DRVrtv (p = 0.05). Conclusions: DRV Ctrough was lower in HIV-infected subjects receiving DRVcobi than with DRVrtv . However, this did not appear to influence the efficacy of DRVcobi , when administered as monotherapy.engVoRhttp://creativecommons.org/licenses/by/4.0/CtroughDarunavirCobicistatMonotherapyPharmacokineticRitonavirAdultAnti-HIV AgentsCobicistatDarunavirDrug Therapy, CombinationFemaleHIV InfectionsHumansMaleMiddle AgedProspective StudiesReverse Transcriptase InhibitorsRitonavirViral LoadAttribution 4.0 International2943085421210.1002/jia2.250721758-2652Journal of the International AIDS Societyopen access