RESUMO
INTRODUCTION: The DOLAM trial revealed that switching from triple antiretroviral therapy (three-drug regimen; 3DR) to dolutegravir plus lamivudine (two-drug regimen; 2DR) was virologically non-inferior to continuing 3DR after 48â weeks of follow-up. Weight increased with 2DR relative to 3DR but it did not impact on metabolic parameters. METHODS: Multiomics plasma profile was performed to gain further insight into whether this therapy switch might affect specific biological pathways. DOLAM (EudraCT 201500027435) is a Phase 4, randomized, open-label, non-inferiority trial in which virologically suppressed persons with HIV treated with 3DR were assigned (1:1) to switch to 2DR or to continue 3DR for 48â weeks. Untargeted proteomics, metabolomics and lipidomics analyses were performed at baseline and at 48â weeks. Univariate and multivariate analyses were performed to identify changes in key molecules between both therapy arms. RESULTS: Switching from 3DR to 2DR showed a multiomic impact on circulating plasma concentration of N-acetylmuramoyl-L-alanine amidase (Q96PD5), insulin-like growth factor-binding protein 3 (A6XND0), alanine and triglyceride (TG) (48:0). Correlation analyses identified an association among the up-regulation of these four molecules in persons treated with 2DR. CONCLUSIONS: Untargeted multiomics profiling studies identified molecular changes potentially associated with inflammation immune pathways, and with lipid and glucose metabolism. Although these changes could be associated with potential metabolic or cardiovascular consequences, their clinical significance remains uncertain. Further work is needed to confirm these findings and to assess their long-term clinical consequences.
Assuntos
Infecções por HIV , Compostos Heterocíclicos com 3 Anéis , Lamivudina , Oxazinas , Piperazinas , Piridonas , Humanos , Compostos Heterocíclicos com 3 Anéis/uso terapêutico , Compostos Heterocíclicos com 3 Anéis/administração & dosagem , Infecções por HIV/tratamento farmacológico , Lamivudina/uso terapêutico , Lamivudina/administração & dosagem , Masculino , Oxazinas/uso terapêutico , Feminino , Adulto , Pessoa de Meia-Idade , Metabolômica , Lipidômica , Fármacos Anti-HIV/uso terapêutico , Fármacos Anti-HIV/administração & dosagem , Plasma/química , Proteômica , Terapia Antirretroviral de Alta Atividade , Substituição de Medicamentos , Triglicerídeos/sangue , Alanina/sangue , MultiômicaRESUMO
A major concern of human immunodeficiency virus (HIV) dual therapy is a potentially lower efficacy in viral reservoirs, especially in the central nervous system (CNS). We evaluated HIV RNA, neuronal injury, and inflammatory biomarkers and dolutegravir (DTG) exposure in cerebrospinal fluid (CSF) in patients switching to DTG plus lamivudine (3TC). All participants maintained viral suppression in plasma and CSF at week 48. We observed no increase in CSF markers of inflammation or neuronal injury. Median (interquartile range) total and unbound DTG in CSF were 7.3 (5.9-8.4) and 1.7 (1.2-1.9) ng/mL, respectively. DTG+3TC may maintain viral control without changes in inflammatory/injury markers within the CNS reservoir.
Assuntos
Fármacos Anti-HIV , Substituição de Medicamentos , Infecções por HIV , Fármacos Anti-HIV/uso terapêutico , Biomarcadores/líquido cefalorraquidiano , Infecções por HIV/tratamento farmacológico , HIV-1 , Compostos Heterocíclicos com 3 Anéis/uso terapêutico , Humanos , Lamivudina/uso terapêutico , Oxazinas/uso terapêutico , Piperazinas/uso terapêutico , Piridonas/uso terapêutico , Carga ViralRESUMO
BACKGROUND: The pharmacokinetics of bictegravir (BIC) and its association with the decay of human immunodeficiency virus (HIV)-1 RNA in genital fluids and the rectum have not yet been addressed. METHODS: We conducted a prospective, multicenter study of antiretroviral-naive people living with HIV-1 and initiating BIC/emtricitabine (FTC)/tenofovir alafenamide (TAF). HIV-1 RNA was measured (limit of quantification, 40 copies/mL) in blood plasma (BP), seminal plasma (SP), rectal fluid (RF), and cervicovaginal fluid (CVF) at baseline; Days 3, 7, 14, and 28; and Weeks 12 and 24. Total and protein-unbound BIC concentrations at 24 hours postdose (C24h) were quantified in BP, SP, CVF and rectal tissue (RT) on Day 28 and Week 12 using a validated liquid chromatography-tandem mass spectrometry assay. RESULTS: The study population comprised 15 males and 8 females. In SP, RF, and CVF, the baseline HIV-1 RNA was >40 copies/mL in 12/15, 13/15, and 4/8 individuals, respectively, with medians of 3.54 (2.41-3.79), 4.19 (2.98-4.70), and 2.56 (1.61-3.56) log10 copies/mL, respectively. The initial decay slope was significantly lower in SP than in RF and BP. The time to undetectable HIV-1 RNA was significantly shorter in SP and RF than in BP. All women achieved undetectable HIV-1 RNA in CVF at Day 14. The median total BIC concentrations in SP, RT, and CVF were 65.5 (20.1-923) ng/mL, 74.1 (6.0-478.5) ng/g, and 61.6 (14.4-1760.2) ng/mL, respectively, representing 2.7%, 2.6%, and 2.8% of the BP concentration, respectively, while the protein-unbound fractions were 51.1%, 44.6%, and 42.6%, respectively. CONCLUSIONS: BIC/FTC/TAF led to rapid decay of HIV-1 RNA in genital and rectal fluids. Protein-unbound BIC concentrations in SP, RT, and CVF highly exceeded the half-maximal effective concentration (EC50) value (1.1 ng/mL). CLINICAL TRIALS REGISTRATION: EudraCT 2018-002310-12.
Assuntos
Fármacos Anti-HIV , Infecções por HIV , HIV-1 , Adulto , Alanina , Amidas , Fármacos Anti-HIV/uso terapêutico , Emtricitabina/uso terapêutico , Feminino , Genitália , Infecções por HIV/tratamento farmacológico , HIV-1/genética , Compostos Heterocíclicos com 3 Anéis , Humanos , Masculino , Piperazinas , Estudos Prospectivos , Piridonas , RNA/uso terapêutico , Reto , Tenofovir/análogos & derivadosRESUMO
BACKGROUND: This study assessed the penetration and efficacy of tenofovir alafenamide (TAF) in the male genital tract (MGT) and the semen quality of individuals infected with human immunodeficiency virus (HIV)-1 who were treated with a TAF-containing regimen. METHODS: This was a prospective, open-label, single-arm study of 14 virologically-suppressed, HIV-1-infected men on stable antiretroviral therapy with elvitegravir, cobicistat, emtricitabine (E/C/F) and tenofovir disoproxil fumarate (TDF) who switched to E/C/F and TAF. At baseline (pre-switch) and at 12 weeks post-switch, we measured HIV-1 RNA in seminal plasma (SP) and blood plasma (BP), tenofovir (TFV) in SP and BP, and TFV-diphosphate (dp) in peripheral blood mononuclear cells (PBMCs) and seminal mononuclear cells (SMCs) at the end of the dosing interval (C24h). Semen quality was assessed before switching and after 12 weeks on TAF. RESULTS: With TAF, TFV C24 was 11.9-fold higher in SP than in BP. This concentration was significantly lower than TFV C24 in SP with TDF, but 9.6-fold higher than the 50% inhibitory concentration (IC50) (11.5 ng/mL). By contrast, the median TFV-dp concentration achieved with TAF in SMCs was 6% that of TFV-dp in PBMCs. The TFV-dp SMC:PBMC ratio was also significantly lower with TAF. Nonetheless, TFV-dp C24 in SMC was comparable with TAF and TDF. All the patients had HIV-1 RNA <40 copies/mL in BP and SP at baseline and at 12 weeks post-switch. No significant differences were observed in semen quality between TAF and TDF. CONCLUSIONS: Extracellular and intracellular seminal TFV distribution differs between TAF and TDF. Nevertheless, both formulations, combined with elvitegravir/cobicistat/emtricitabine, maintained HIV-1 RNA suppression in semen. Differences in MGT distribution were not associated with differences in semen quality. CLINICAL TRIALS REGISTRATION: EudraCT: 2016-001371-69.
Assuntos
Adenina/análogos & derivados , Antirretrovirais/uso terapêutico , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Tenofovir/uso terapêutico , Adenina/uso terapêutico , Adulto , Alanina , Cobicistat/uso terapêutico , Emtricitabina/uso terapêutico , Infecções por HIV/virologia , HIV-1/genética , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Quinolonas/uso terapêutico , RNA Viral/análise , RNA Viral/efeitos dos fármacos , Sêmen , Análise do SêmenRESUMO
This study aimed to assess cerebrospinal fluid (CSF) drug concentrations and viral suppression in HIV-1-infected patients on ritonavir-boosted atazanavir (ATV/r) plus lamivudine (3TC) dual therapy. HIV-1-infected adults with suppressed plasma HIV-1 RNA who switched to ATV/r plus 3TC were studied. Total ATV and 3TC concentrations at the end of the dosing interval (C24h), using a validated LC-MS/MS method, and HIV-1 RNA were measured in paired CSF and plasma samples 12 weeks after switching. Ten individuals were included. Median (range) age was 42.5 (33-70) years, time on ART was 39.5 (11-197) months, and time with plasma HIV-1 RNA < 40 copies/mL was 15.5 (6-46) months. At baseline, CSF HIV-1 RNA was < 40 copies/mL in all patients. Twelve weeks after switching to ATV/r plus 3TC, HIV-1 RNA remained at < 40 copies/mL in both plasma and CSF in 9/10 patients. One patient with suboptimal adherence to ART had HIV-1 RNA rebound in both plasma and CSF. The median CSF-to-plasma concentration ratios of ATV and 3TC were 0.013 and 0.417, respectively. Median ATV C24h in CSF was 10.4 (3.7-33.4) ng/mL (in vitro ATV IC50 range, 1-11 ng/mL). Median 3TC C24h in CSF was 43.4 (16.2-99.3) ng/mL (in vitro 3TC IC50 range, 0.68-20.6 ng/mL). Most patients maintained HIV-1 RNA in CSF < 40 copies/mL despite CSF ATV C24h close to or within the IC50 range in the majority. ATV PK data in CSF should be considered and rigorous patient selection is advisable to assure effective CSF viral suppression with this two-drug simplification regimen.
Assuntos
Fármacos Anti-HIV/líquido cefalorraquidiano , Fármacos Anti-HIV/uso terapêutico , Terapia Antirretroviral de Alta Atividade/métodos , Infecções por HIV/tratamento farmacológico , Adulto , Idoso , Sulfato de Atazanavir/administração & dosagem , Sulfato de Atazanavir/líquido cefalorraquidiano , Quimioterapia Combinada/métodos , Feminino , HIV-1 , Humanos , Lamivudina/administração & dosagem , Lamivudina/líquido cefalorraquidiano , Masculino , Pessoa de Meia-Idade , RNA Viral/sangue , RNA Viral/líquido cefalorraquidiano , Ritonavir/administração & dosagem , Ritonavir/líquido cefalorraquidiano , Carga Viral/efeitos dos fármacosRESUMO
BACKGROUND: The objective of this study was to determine the impact of tenofovir or abacavir discontinuation on low-density lipoprotein (LDL) phenotype and lipoprotein-associated phospholipase A2 (Lp-PLA2) activity in HIV-infected patients treated with lopinavir/ritonavir plus 2 nucleos(t)ide reverse transcriptase inhibitors (NRTI). METHODS: Multicenter, open-label study. Patients were randomized to continue with lopinavir/ritonavir plus 2 NRTI (triple therapy) or to switch to lopinavir/ritonavir plus lamivudine (dual therapy). LDL phenotype (by gradient gel electrophoresis) and Lp-PLA2 (by 2-thio-PAF) were determined at baseline and week 48. RESULTS: Forty-four patients included (triple therapy n = 19, dual therapy n = 25): men 63.6%, age 41.5 years (25-61), Framingham score 4.9% (0.2-22). Tenofovir was part of the regimen in 28 (63.6%) patients. Dual therapy patients were younger (p = 0.013) and had lower baseline apolipoprotein A1 (p = 0.029). At week 48, there were no changes in standard lipid measurements, except ApoA1/Apo B, which increased in dual therapy (p = 0.038) with no differences between arms. At week 48, no change in LDL phenotype was found in either arm. No changes in total Lp-PLA2 activity or the relative distribution of LDL and HDL particles were found at week 48 in either arm. CONCLUSIONS: Discontinuing the third nucleos(t)ide, mainly tenofovir and abacavir, in a lopinavir/ritonavir-containing regimen was not associated with a deleterious effect on LDL phenotype nor in Lp-PLA2 activity.
Assuntos
Didesoxinucleosídeos/efeitos adversos , Infecções por HIV/metabolismo , Lamivudina/efeitos adversos , Lipoproteínas LDL/metabolismo , Lopinavir/efeitos adversos , 1-Alquil-2-acetilglicerofosfocolina Esterase/sangue , 1-Alquil-2-acetilglicerofosfocolina Esterase/metabolismo , Fármacos Anti-HIV , Terapia Antirretroviral de Alta Atividade/efeitos adversos , Biomarcadores , Contagem de Linfócito CD4 , Didesoxinucleosídeos/administração & dosagem , Combinação de Medicamentos , Substituição de Medicamentos , Feminino , Infecções por HIV/sangue , Infecções por HIV/diagnóstico , Infecções por HIV/tratamento farmacológico , Humanos , Lamivudina/administração & dosagem , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipídeos/sangue , Lipoproteínas LDL/sangue , Lopinavir/administração & dosagem , Masculino , Carga ViralRESUMO
To investigate the pharmacokinetics/pharmacodynamics of single-dose maraviroc 300 mg in HIV-1 exposure compartments. Maraviroc concentrations in blood, secretions (vaginal, urethral, oral, and rectal), and tissue (vaginal and rectal) were measured, and ex vivo challenge was performed in 54 healthy volunteers to study protection from HIV infection. Maraviroc Cmax occurred within 4 hours in most compartments. Concentrations from 4 to 72 hours were above intracellular (IC) IC90 in all compartments, range 15-8095 ng/mL. Mean AUC0-72 compartment-to-plasma ratios were highest in the rectum (45-819) and urethra (144) compared with the female genital tract (1.6-4.8) and saliva (0.2). No sex differences in AUC0-72 or Cmax were observed. No ex vivo protection from HIV-1BaL occurred in rectal or vaginal tissue. Despite high and sustained concentrations, single-dose maraviroc was not protective against ex vivo challenge of vaginal/rectal tissue.
Assuntos
Antagonistas dos Receptores CCR5/farmacocinética , Cicloexanos/farmacocinética , Inibidores da Fusão de HIV/farmacocinética , Infecções por HIV/prevenção & controle , Infecções por HIV/virologia , Profilaxia Pré-Exposição , Triazóis/farmacocinética , Administração Oral , Adulto , Antagonistas dos Receptores CCR5/administração & dosagem , Antagonistas dos Receptores CCR5/farmacologia , Cicloexanos/administração & dosagem , Cicloexanos/farmacologia , Feminino , Inibidores da Fusão de HIV/administração & dosagem , Inibidores da Fusão de HIV/farmacologia , HIV-1/efeitos dos fármacos , Voluntários Saudáveis , Humanos , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/virologia , Masculino , Maraviroc , Modelos Biológicos , Ensaios Clínicos Controlados Aleatórios como Assunto , Reto/efeitos dos fármacos , Reto/virologia , Saliva/efeitos dos fármacos , Saliva/virologia , Resultado do Tratamento , Triazóis/administração & dosagem , Triazóis/farmacologia , Uretra/efeitos dos fármacos , Uretra/virologia , Vagina/efeitos dos fármacos , Vagina/virologiaRESUMO
BACKGROUND: Lopinavir/ritonavir (LPV/r) monotherapy is used in selected virologically suppressed HIV-infected patients. Some would prefer a once-daily (OD) dose instead of the usual twice-daily dose to favour adherence. However, trough concentrations of the drug in blood and particularly in cerebrospinal fluid (CSF) may not be adequate to maintain viral suppression. METHODS: Prospective, open-label pilot study to evaluate the efficacy and safety of LPV/r monotherapy OD. HIV-1-infected patients, virologically suppressed for at least 6 months were enrolled. HIV viral load (VL) was determined at baseline and at weeks 4, 8, 12, 16, 24, 36 and 48. Lumbar puncture was performed in a subgroup of patients to evaluate CSF VL and CSF LPV concentrations. RESULTS: A total of 21 patients were included. At week 48, 85.7% (n=18) showed viral suppression (VL<40 copies/ml). Two patients had viral failure (9.5%) and a third was withdrawn from the study because of gastrointestinal symptoms. Nine patients were enrolled in the substudy. CSF VL was <40 copies/ml in all cases. Median (range) LPV concentration was 9.78 ng/ml (1.93-78.3) in CSF and 1,970 (154-16,700) ng/ml in plasma; the CSF/plasma ratio was 0.004 (0.001-0.186). CONCLUSIONS: In this small pilot study, LPV/r monotherapy OD maintained plasma HIV RNA suppression at 48 weeks in most patients, with no cases of CSF viral escape. However, CSF LPV concentrations were close to the 50% inhibitory concentration threshold in several patients; hence, this intervention should be avoided in patients with advanced immune suppression and/or those individuals presenting with significant comorbidities such as hepatitis C coinfection.
Assuntos
Fármacos Anti-HIV/sangue , Fármacos Anti-HIV/líquido cefalorraquidiano , Infecções por HIV/tratamento farmacológico , Lopinavir/sangue , Lopinavir/líquido cefalorraquidiano , Ritonavir/uso terapêutico , Adulto , Fármacos Anti-HIV/uso terapêutico , Esquema de Medicação , Combinação de Medicamentos , Feminino , Infecções por HIV/sangue , Humanos , Lopinavir/uso terapêutico , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Falha de TratamentoRESUMO
BACKGROUND: Efavirenz (EFV) has been associated with reductions in vitamin D (25[OH]D) and tenofovir (TDF) with increased bone turnover, reductions in bone mineral density (BMD) and renal tubular dysfunction. We hypothesized that switching from fixed-dose TDF/emtricitabine (FTC)/EFV to darunavir/ritonavir monotherapy (DRV/r) might increase 25(OH)D and BMD, and improve renal tubular function. METHODS: Subjects with HIV RNA <50 copies/ml on TDF/FTC/EFV for ≥6 months were randomized 1:1 to ongoing TDF/FTC/EFV or DRV/r (800/100 mg once daily) for 48 weeks. The primary end point was change from baseline in 25(OH)D at week 48. Secondary end points included changes in BMD, bone turnover markers and renal tubular function. RESULTS: A total of 64 subjects (86% male, 66% white, mean [sd] CD4(+) T-cell count 537.3 [191.5]/mm(3)) were analysed. After adjustment for baseline 25(OH)D and demographics, at week 48 DRV/r monotherapy was associated with a +3.6 (95% CI 0.6, 6.6) ng/ml increase in 25(OH)D compared to TDF/FTC/EFV (P=0.02). DRV/r monotherapy was associated with an increase in BMD (+2.9% versus -0.003% at the neck of femur and +2.6% versus +0.008% at the lumbar spine for DRV/r versus TDF/FTC/EFV; P<0.05 for all) and reductions in bone biomarkers compared with those remaining on TDF/FTC/EFV. No significant difference in renal tubular function was observed. Reasons for discontinuation in the DRV/r arm included side effects (n=4) and viral load rebound (n=3), all of which resolved with DRV/r discontinuation or regimen intensification. CONCLUSIONS: Switching from TDF/FTC/EFV to DRV/r in patients with suppressed HIV RNA resulted in significant improvements in 25(OH)D and bone biomarkers, and a 2-3% increase in BMD.
Assuntos
Fármacos Anti-HIV/farmacologia , Osso e Ossos/efeitos dos fármacos , Infecções por HIV/tratamento farmacológico , Rim/efeitos dos fármacos , Vitamina D/sangue , Adulto , Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/efeitos adversos , Fármacos Anti-HIV/uso terapêutico , Densidade Óssea/efeitos dos fármacos , Calcifediol/sangue , Darunavir/efeitos adversos , Darunavir/uso terapêutico , Combinação Efavirenz, Emtricitabina, Fumarato de Tenofovir Desoproxila/efeitos adversos , Combinação Efavirenz, Emtricitabina, Fumarato de Tenofovir Desoproxila/farmacologia , Combinação Efavirenz, Emtricitabina, Fumarato de Tenofovir Desoproxila/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ritonavir/efeitos adversos , Ritonavir/uso terapêuticoRESUMO
OBJECTIVES: The objective of this study was to assess whether a lower dose than the currently used one of darunavir/ritonavir might achieve good CSF concentrations and contribute to inhibition of CNS viral replication. PATIENTS AND METHODS: This was a substudy of a randomized, open, multicentre study (eudraCT 2011-006272-39), comparing the efficacy and safety of 800/100 mg of darunavir/ritonavir (darunavir 800) versus 600/100 mg of darunavir/ritonavir (darunavir 600) once daily plus tenofovir/emtricitabine or abacavir/lamivudine in 100 virologically suppressed patients. Paired blood and CSF samples were obtained. Total plasma darunavir concentrations were determined by HPLC, and CSF concentrations by liquid chromatography-tandem MS. Viral load (VL) was determined in plasma and CSF (limit of detectionâ=â40 copies/mL) by PCR. RESULTS: Sixteen patients were enrolled. The median (range) of darunavir CSF concentrations in darunavir 600 (nâ=â8) and darunavir 800 (nâ=â8) patients was 17.08 (5.79-30.19) and 13.23 (3.47-32.98) ng/mL, respectively (Pâ=â0.916). The median (range) darunavir CSF:plasma ratio was 0.010 (0.005-0.022) in darunavir 600 patients and 0.008 (0.004-0.017) in the darunavir 800 arm (Pâ=â0.370). All 16 patients had a VLâ<â40 copies/mL in plasma and 14 had a VLâ<â40 copies/mL in CSF. Of the two patients with detectable CSF VL (280 copies/mL and 159 copies/mL), one was receiving darunavir 600 and the other darunavir 800 plus tenofovir/emtricitabine. Of note, these patients had the lowest CSF darunavir concentrations in their respective groups: 5.79 ng/mL (802 ng/mL in plasma) and 3.47 ng/mL (958 ng/mL in plasma). CONCLUSIONS: Darunavir CSF and plasma concentrations were comparable between the two arms. However, one patient from each group (with the lowest CSF darunavir concentrations in their respective groups) had detectable CSF VL despite undetectable plasma VL.
Assuntos
Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/farmacocinética , Líquido Cefalorraquidiano/química , Darunavir/administração & dosagem , Darunavir/farmacocinética , Ritonavir/administração & dosagem , Ritonavir/farmacocinética , Adolescente , Adulto , Idoso , Fármacos Anti-HIV/farmacologia , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Darunavir/farmacologia , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , HIV-1/isolamento & purificação , Humanos , Masculino , Pessoa de Meia-Idade , Plasma/química , Ritonavir/farmacologia , Espectrometria de Massas em Tandem , Carga Viral , Viremia/tratamento farmacológico , Viremia/virologia , Adulto JovemRESUMO
BACKGROUND: There are no clinical trials in which the main objective is to compare the efficacy of efavirenz versus ritonavir-boosted protease inhibitor (PI/r)-based initial antiretroviral therapy (ART) in patients with high plasma HIV-1 RNA levels. This study aims to compare these regimens in this patient population in the setting of routine clinical practice. METHODS: This was a multicentre, observational cohort study, including 596 consecutive treatment-naive patients with plasma HIV-1 RNA>100,000 copies/ml initiating efavirenz or PI/r-based ART between 2000 and 2010. The primary effectiveness end point was the percentage of patients with HIV-1 RNA<50 copies/ml at week 48 by intent-to-treat analysis. RESULTS: Among a total of 596 patients, 57% initiated efavirenz and 43% PI/r-regimens (73% lopinavir and fosamprenavir [62% lopinavir, 11% fosamprenavir]). HIV-1 RNA suppression to <50 copies/ml at week 48 was higher in the efavirenz group (84% versus 74% [difference 10%, 95% CI 3.4%, 16.7%; P=0.002]). The percentage of virological failures was similar (efavirenz 4% versus PI/r 4%; P=0.686), but voluntary discontinuations and toxicity-related treatment changes were higher with PI/r (4% versus 1%; P=0.006 and 11% versus 6%; P=0.069, respectively). However, resistance selection at failure was higher in patients receiving efavirenz (89% versus 50%; P=0.203). Efavirenz was significantly more effective than lopinavir/r or fosamprenavir/r, whereas no significant differences were observed between efavirenz and darunavir/r or atazanavir/r. The high viral suppression in the efavirenz group was also evident in patients with very high viral loads (>500,000 copies/ml) and in those with low CD4(+) T-cell counts. CONCLUSIONS: In routine clinical practice, the effectiveness of initial efavirenz-based regimens was at least similar to or even higher than various PI/r-based regimens in HIV-1-infected patients with plasma HIV-1 RNA>100,000 copies/ml.