No difference in effectiveness of treatment simplification to boosted or unboosted atazanavir plus lamivudine in virologically suppressed in HIV-1-infected patients.

BACKGROUND: Simplification strategies of antiretroviral treatment represent effective tools for the reduction of drug-induced toxicity, resistance mutations in case of virological failure and costs. OBJECTIVES: To assess the effectiveness of simplification to atazanavir/ritonavir (ATVrtv) or unboosted atazanavir (ATV400) plus lamivudine, and if low plasma or intracellular ATV Ctrough influence virological outcomes. METHODS: Ambispective observational study in patients with undetectable HIV-RNA who were switched to ATVrtv or ATV400 plus lamivudine once daily. Previous virological failures (VF) were allowed if the resistance tests showed major resistance mutation neither to ATV nor to lamivudine. VF was defined as two consecutive plasma HIV-RNA >200 copies/mL. Effectiveness was assessed by intention-to-treat and on-treatment analyses. Plasma and intracellular ATV Ctrough were measured by LC-MS/MS. RESULT: A total of 246 patients were included. At week 48, the Kaplan-Meier estimation of efficacy within the ATVrtv and ATV400 groups were 85.9% [95% confidence interval, (CI95), 80.3-91.4%] versus 87.6% (CI95, 80.1-94.1%) by intention-to-treat analysis (p = 0.684), and 97.7% (CI95, 95.2-100%) versus 98.8% (CI95, 97.0-100%) by on-treatment analysis (p = 0.546), respectively. Plasma and intracellular Ctrough were significantly higher with ATVrtv than with ATV400 (geometric mean (GM), 318.3 vs. 605.9 ng/mL; p = 0.013) and (811.3 vs. 2659.2 ng/mL; p = 0.001), respectively. Only 14 patients had plasma Ctrough below the suggested effective concentration for ATV (150 ng/mL). No relationship between plasma or intracellular Ctrough and VF or blips were found. CONCLUSION: Boosted or unboosted ATV plus lamivudine is effective and safe, and the lower plasma Ctrough observed with ATV400 do not compromise the effectiveness of these simplification regimens in long-term virologically suppressed HIV-1-infected patients.

Darunavir/cobicistat showing similar effectiveness as darunavir/ritonavir monotherapy despite lower trough concentrations.

INTRODUCTION: 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.

Viral Kinetics in Semen With Different Antiretroviral Families in Treatment-Naive Human Immunodeficiency Virus-Infected Patients: A Randomized Trial.

BACKGROUND: There are several regimens for starting antiretroviral treatment, but it remains unknown whether either of them is more advantageous regarding the time course and magnitude of human immunodeficiency virus (HIV) RNA decay in semen. OBJECTIVE: To evaluate the differential effect of different antiretroviral drug families on viral kinetics in seminal plasma (SP) of treatment-naive HIV-infected patients. METHODS: Phase II, randomized, open-label study in which participants were randomized 1:1:1 to receive tenofovir-disoproxil fumarate (DF) plus emtricitabine, and either cobicistat-boosted elvitegravir (EVGcobi), rilpivirine (RPV), or ritonavir-boosted darunavir (DRVrtv). The primary endpoint was the proportion of participants with undetectable HIV-RNA in SP at week 12. HIV type 1 (HIV-1) RNA was measured in paired SP and blood plasma (BP) at baseline and after 1, 2, 4, 6, 8, 12, 18, and 24 weeks. Elvitegravir (EVG), RPV, and darunavir (DRV) concentrations were quantified by the liquid chromatography-tandem mass spectrometry method. RESULTS: In SP, the HIV-RNA decay rate with RPV was as fast as with EVGcobi; by week 12, all participants in the RPV and the EVGcobi groups reached an undetectable viral load but only 58.3% in the DRVrtv arm (P = .003). The highest SP/BP drug concentration ratio was for EVG (0.43), followed-up by RPV (0.19), and DRV (0.10). For both EVG and RPV, the SP concentrations exceeded >2-fold the protein binding-adjusted EC90 for wild-type HIV-1; for DRV, only 33.7% of the SP showed concentrations above the protein binding-adjusted EC90. CONCLUSIONS: In SP, both RPV and EVGcobi, associated to tenofovir-DF and emtricitabine, behave similarly and achieve an undetectable viral load much faster than DRVrtv. REGISTRATION: European Medical Agency (No. EudraCT: 2014-001348-39).

Pharmacokinetic interactions between cobicistat-boosted elvitegravir and darunavir in HIV-infected patients.

Objectives: To evaluate if there are significant drug-drug interactions between cobicistat-boosted elvitegravir and 800 mg darunavir once daily taken simultaneously, as has been suggested previously. Methods: The study population consisted of three groups of unselected volunteers taking a regimen of elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate (150, 150, 200 and 300 mg, respectively) co-formulated in a single tablet plus 800 mg darunavir (group A); only co-formulated elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate (group B); and cobicistat-boosted darunavir (800 mg darunavir + 150 mg cobicistat) plus two nucleos(t)ide analogues (group C). Elvitegravir, cobicistat and darunavir concentrations at the end of the dosing interval ( C 24 ) were quantified using a validated LC with tandem MS method. Results: A total of 170 samples were obtained from 24, 32 and 32 patients in groups A, B and C, respectively. In group A, the elvitegravir C 24 were similar to those in group B (233.67 versus 250.39 ng/mL) ( P = 0.406) and the darunavir C 24 were similar to those in group C (1293.54 versus 1319.34 ng/mL) ( P = 0.908). The cobicistat C 24 were comparable in groups A and B (20.2 versus 20.9 ng/mL) and slightly higher in group C (27.7 ng/mL) ( P = 0.059). Conclusions: The results provide evidence of similar elvitegravir and darunavir C 24 concentrations when these drugs are co-administered as co-formulated elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate plus 800 mg darunavir or dosed separately.