Virological characterization of patients failing darunavir/ritonavir or lopinavir/ritonavir treatment in the ARTEMIS study: 96-week analysis.

Background: In the Phase III ARTEMIS Trial, treatment-naive patients received once-daily darunavir/ritonavir (DRV/r) 800/100 mg (n = 343) or lopinavir/ritonavir (LPV/r) 800/200 mg (total daily dose; n = 346) plus fixed-dose tenofovir disoproxil fumarate/emtricitabine. The primary outcome measure was non-inferiority of DRV/r versus LPV/r (HIV type-1 [HIV-1] RNA<50 copies/ml). Here, a detailed 96-week resistance analysis is presented.

In vitro susceptibility and virological outcome to darunavir and lopinavir are independent of HIV type-1 subtype in treatment-naive patients.

Background: The effect of HIV type-1 (HIV-1) subtype on in vitro susceptibility and virological response to darunavir (DRV) and lopinavir (LPV) was studied using a broad panel of primary isolates, and in recombinant clinical isolates from treatment-naive, HIV-1-infected patients in the Phase III trial, AntiRetroviral Therapy with TMC114 ExaMined In naive Subjects (ARTEMIS).

Methods: Patients received DRV/ritonavir (DRV/r) 800/100 mg once daily (n=343) or LPV/ritonavir (LPV/r) 800/200 mg total daily dose (n=346), plus a fixed daily dose of emtricitabine and tenofovir disoproxil fumarate.

Results: DRV demonstrated high antiviral activity against a broad panel of HIV-1 major group (M) and outlier group (O) primary isolates in peripheral blood mononuclear cells, with a median 50% effective concentration (EC(50)) of 0.

Characterization of genotypic and phenotypic changes in HIV-1-infected patients with virologic failure on an etravirine-containing regimen in the DUET-1 and DUET-2 clinical studies.

The randomized, placebo-controlled Phase III DUET studies enrolled treatment-experienced, HIV-1-infected patients. We examined the genotypic and phenotypic changes at endpoint relative to baseline, including the emergence of individual reverse transcriptase (RT) mutations, in patients who received the non-nucleoside reverse transcriptase inhibitor (NNRTI) etravirine and experienced virologic failure by rebound by the time of the Week 96 analysis. Patients received etravirine 200 mg twice-daily in combination with a background regimen containing darunavir/ritonavir, investigator-selected nucleoside reverse transcriptase inhibitors, and optional enfuvirtide.

Short communication: activity of etravirine on different HIV type 1 subtypes: in vitro susceptibility in treatment-naive patients and week 48 pooled DUET study data.

Etravirine (ETR) has previously shown potent in vitro activity against different primary HIV-1 isolates and demonstrated durable efficacy in treatment-experienced, HIV-1-infected patients in the Phase III DUET studies. The antiviral activity and efficacy of ETR against HIV-1 subtypes B and non-B were further investigated. The effect of HIV-1 subtype on ETR fold change in EC(50) value (FC) was analyzed in HIV-1 recombinant clinical isolates from 673 treatment-naive patients enrolled in other Tibotec studies.

Resistance profile of etravirine: combined analysis of baseline genotypic and phenotypic data from the randomized, controlled Phase III clinical studies.

Objective: To refine the genotypic and phenotypic correlates of response to the nonnucleoside reverse transcriptase inhibitor etravirine.

Design: Initial analyses identified 13 etravirine resistance-associated mutations (RAMs) and clinical cutoffs (CCOs) for etravirine. A multivariate analysis was performed to refine the initial etravirine RAM list and improve the predictive value of genotypic resistance testing with regard to virologic response and relationship to phenotypic data.

TMC278, a next-generation nonnucleoside reverse transcriptase inhibitor (NNRTI), active against wild-type and NNRTI-resistant HIV-1.

Nonnucleoside reverse transcriptase inhibitors (NNRTIs) have proven efficacy against human immunodeficiency virus type 1 (HIV-1). However, in the setting of incomplete viral suppression, efavirenz and nevirapine select for resistant viruses. The diarylpyrimidine etravirine has demonstrated durable efficacy for patients infected with NNRTI-resistant HIV-1.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs), their discovery, development, and use in the treatment of HIV-1 infection: a review of the last 20 years (1989-2009).

It is almost 20 years since NNRTIs were identified as a new class of antiretroviral drugs for the treatment of HIV-1 infection. Although they belong to different and diverse chemical families, they share a common and unique mechanism of action: their interaction with HIV-1 reverse transcriptase induces conformational changes that inhibit the catalytic activities of the enzyme. They are characterized by their specificity for HIV-1, which makes them very selective inhibitors of the virus.

Short-term randomized proof-of-principle trial of TMC278 in patients with HIV type-1 who have previously failed antiretroviral therapy.

Background: In vitro, TMC278, an investigational next-generation non-nucleoside reverse transcriptase inhibitor (NNRTI), has shown activity against wild-type and NNRTI-resistant HIV type-1 (HIV-1) and a higher genetic barrier to the development of resistance than efavirenz or nevirapine. This Phase II open-label trial evaluated the short-term (7-day) antiviral activity of TMC278 administered at three different doses replacing either the protease inhibitor (PI) or NNRTI of an ongoing failing treatment regimen in HIV-1-infected patients.

Methods: A total of 36 patients on failing antiretroviral therapy containing either an NNRTI or a PI (with evidence of > or =1 NNRTI resistance-associated mutation at screening for the PI group) and plasma viral load (VL)>1,000 copies/ml were randomized to one of three once-daily TMC278 doses (25 mg, 50 mg or 150 mg) for 7 days, while continuing NRTIs used at screening.

Synthesis and biological evaluation of C-5 methyl substituted 4-arylthio and 4-aryloxy-3-Iodopyridin-2(1H)-one type anti-HIV agents.

A series of C-5 methyl substituted 4-arylthio- and 4-aryloxy-3-iodopyridin-2(1H)-ones has been synthesized as new pyridinone analogues for their evaluation as anti-HIV inhibitors. The optimization at the 5-position was developed through an efficient use of the key intermediates 5-ethoxycarbonyl- and 5-cyano-pyridin-2(1H)-ones (14 and 15). Biological studies revealed that several compounds show potent HIV-1 reverse transcriptase inhibitory properties, for example, compounds 93 and 99 are active at 0.

Characterization of virologic failure patients on darunavir/ritonavir in treatment-experienced patients.

Objective: Characterization of resistance development in virologic failure patients on the protease inhibitor darunavir administered with low-dose ritonavir (DRV/r) in the 48-week analysis of TMC114/r In Treatment-experienced pAtients Naive to lopinavir (TITAN).

Design: TITAN is a randomized, controlled, open-label, phase III, noninferiority trial comparing the efficacy and safety of DRV/r with that of lopinavir/ritonavir (LPV/r) in HIV-1-infected, treatment-experienced, LPV-naive patients. The primary endpoint was the proportion of patients with HIV-1 RNA less than 400 copies/ml at week 48.

Compilation and prevalence of mutations associated with resistance to non-nucleoside reverse transcriptase inhibitors.

Background: Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are an important component of antiretroviral therapy for HIV type-1 (HIV-1)-infected patients. Development of NNRTI resistance can lead to treatment failure and is conferred by the presence of specific resistance-associated mutations (RAMs) in the reverse transcriptase. In addition to the widely used list of NNRTI RAMs provided by the International AIDS Society-USA HIV-1 Drug Resistance Mutation Group, which were identified on the basis of clinical experience with the approved NNRTIs, a more comprehensive list of NNRTI RAMs is needed to guide the study of baseline and emerging resistance to new NNRTIs.

Efficacy and safety of etravirine (TMC125) in treatment-experienced HIV-1-infected patients: 48-week results of a phase IIb trial.

Forty-eight-week results from a randomized, multicentre, part-blinded, phase IIb clinical trial assessing the efficacy and safety of 400 and 800 mg etravirine twice daily (phase IIb formulation) and optimized background regimen versus standard-of-care regimen are presented. Both etravirine doses demonstrated sustained virological suppression at 48 weeks and a favourable tolerability profile. Etravirine demonstrated higher efficacy than control, irrespective of the number of detectable nonnucleoside reverse transcriptase inhibitor-resistance-associated mutations at baseline or active background antiretrovirals.

Effect of baseline viral susceptibility on response to darunavir/ritonavir versus control protease inhibitors in treatment-experienced HIV type 1-infected patients: POWER 1 and 2.

Data from two Phase IIb trials, POWER 1 and 2 (TMC114-C213 and C202), were pooled to examine the effect of baseline viral susceptibility on response to control protease inhibitors [CPI(s)] compared with response to darunavir (TMC114) given with low-dose ritonavir (darunavir/r) in treatment-experienced HIV patients. POWER 1 and 2 were randomized, controlled Phase IIb trials with a similar design. Patients with one or more primary PI mutations and HIV-1 RNA >1000 copies/ml were randomized to receive an optimized background regimen plus darunavir/r or CPI(s).

Efficacy of once-daily darunavir/ritonavir 800/100 mg in HIV-infected, treatment-experienced patients with no baseline resistance-associated mutations to darunavir.

Objective: The objective of this study was to examine the potential of once-daily dosing with darunavir/ritonavir 800/100 mg in a HIV-infected, treatment-experienced patient population with no baseline darunavir resistance-associated mutations (RAMs).

Methods: Patients in the randomized controlled POWER 1 and 2 trials were treatment experienced, with > or =1 International AIDS Society-USA primary protease inhibitor (PI) mutation. The virological and immunological responses in patients with no baseline darunavir RAMs receiving darunavir/r 800/100 mg once daily (n = 23), darunavir/r 600/100 mg twice daily (n = 29), or currently available PI(s) (n = 28) plus an optimized background regimen were compared.

Resistance profile of darunavir: combined 24-week results from the POWER trials.

The resistance profile of darunavir (TMC114) in treatment-experienced patients was explored using pooled week 24 data from POWER 1, 2, and 3 at the recommended dose of darunavir with low-dose ritonavir (darunavir/r, 600/100 mg bid, N = 458). Baseline darunavir fold change in EC(50) was a strong predictor of virological response at week 24. Preliminary phenotypic clinical cut-offs of 10 and 40 were established.

Inhibition of human immunodeficiency virus type 1 replication in human cells by Debio-025, a novel cyclophilin binding agent.

Debio-025 is a synthetic cyclosporine with no immunosuppressive capacity but a high inhibitory potency against cyclophilin A (CypA)-associated cis-trans prolyl isomerase (PPIase) activity. A lack of immunosuppressive effects compared to that of cyclosporine was demonstrated both in vitro and in vivo. For three cyclosporines, the inhibitory potential against PPIase activity was quantitatively correlated with that against human immunodeficiency virus type 1 (HIV-1) replication.

Efficacy and safety of darunavir-ritonavir compared with that of lopinavir-ritonavir at 48 weeks in treatment-experienced, HIV-infected patients in TITAN: a randomised controlled phase III trial.

Background: The protease inhibitor darunavir has been shown to be efficacious in highly treatment-experienced patients with HIV infection, but needs to be assessed in patients with a broader range of treatment experience. We did a randomised, controlled, phase III trial (TITAN) to compare 48-week efficacy and safety of darunavir-ritonavir with that of lopinavir-ritonavir in treatment-experienced, lopinavir-naive patients.

Methods: Patients received optimised background regimen plus non-blinded treatment with darunavir-ritonavir 600/100 mg twice daily or lopinavir-ritonavir 400/100 mg twice daily.

Screening and selecting for optimized antiretroviral drugs: rising to the challenge of drug resistance.

Background: Resistance to antiretroviral (ARV) drugs constitutes one of the greatest limitations to effective long-term therapy for human immunodeficiency virus (HIV) infection--a problem alleviated, but by no means overcome, by the application of carefully selected, sequential combination regimens. The rational development of novel therapeutics with the ability to suppress viraemia effectively and also address the complex problems of resistance offers a useful way forward for HIV therapy. The investigational drug TMC114 (darunavir) was designed to be active against both wild-type HIV and strains that are resistant to currently available protease inhibitors.

A dual chamber model of female cervical mucosa for the study of HIV transmission and for the evaluation of candidate HIV microbicides.

A dual chamber system was established to model heterosexual HIV transmission. Cell-associated, but not cell-free HIV, added to a confluent layer of cervical epithelial cells in the apical chamber, reproducibly infected monocyte-derived dendritic cells (MO-DC) and CD4(+) T cells in the basal compartment. Only minimal epithelial transmigration of HIV-infected mononuclear cells (HIV-PBMCs) was observed.

Potent nonnucleoside reverse transcriptase inhibitors target HIV-1 Gag-Pol.

Nonnucleoside reverse transcriptase inhibitors (NNRTIs) target HIV-1 reverse transcriptase (RT) by binding to a pocket in RT that is close to, but distinct, from the DNA polymerase active site and prevent the synthesis of viral cDNA. NNRTIs, in particular, those that are potent inhibitors of RT polymerase activity, can also act as chemical enhancers of the enzyme's inter-subunit interactions. However, the consequences of this chemical enhancement effect on HIV-1 replication are not understood.

Short-term antiviral activity of TMC278--a novel NNRTI--in treatment-naive HIV-1-infected subjects.

Objective: To evaluate antiviral activity, pharmacokinetics, tolerability and safety of TMC278, a non-nucleoside reverse transcriptase inhibitor (NNRTI), when given as a 25, 50, 100 or 150 mg once-daily dose for 7 days to antiretroviral-naive HIV-infected subjects.

Design: Randomized, double-blind, placebo-controlled, phase IIa clinical trial.

Methods: Participants were 47 antiretroviral naive HIV-infected subjects.

Modulation of human immunodeficiency virus type 1 synergistic inhibition by reverse transcriptase mutations.

Synergy between the anti-human immunodeficiency virus type 1 (HIV) nucleoside reverse transcriptase (RT) inhibitors (NRTIs) and nonnucleoside RT inhibitors (NNRTIs) results from a general mechanism in which NNRTIs inhibit ATP-mediated removal of NRTIs from chain-terminated primers by decreasing the maximum rate of removal, thus sustaining NRTI chain termination. With this molecular mechanism of synergy, beta-D-(+)-3'-azido-3'-deoxythymidine monophosphate (AZTMP) removal was examined in the context of clinically relevant RT mutants. The IC50 value for inhibition by nevirapine against wild-type (WT) RT in our removal assay was 3 microM, but this concentration had no effect on removal by the nevirapine-resistant Y181C mutant.

TMC125 displays a high genetic barrier to the development of resistance: evidence from in vitro selection experiments.

TMC125 is a potent new investigational nonnucleoside reverse transcriptase inhibitor (NNRTI) that is active against human immunodeficiency virus type 1 (HIV-1) with resistance to currently licensed NNRTIs. Sequential passage experiments with both wild-type virus and NNRTI-resistant virus were performed to identify mutations selected by TMC125 in vitro. In addition to "classic" selection experiments at a low multiplicity of infection (MOI) with increasing concentrations of inhibitors, experiments at a high MOI with fixed concentrations of inhibitors were performed to ensure a standardized comparison between TMC125 and current NNRTIs.