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. METHODS: Virological failures (VFs) were defined as patients who had lost (rebounders) or who had never achieved (never suppressed) HIV-1 RNA < 50 copies/ml after week 12. Genotypic and phenotypic determinations were performed on plasma samples with HIV-1 RNA ≥ 50 copies/ml. The end point was defined as the last on-treatment visit with available genotype and/or phenotype. RESULTS: The VF rate was significantly lower in DRV/r (12%, n = 40) versus LPV/r patients (17%, n = 59; P = 0.0437). Among DRV/r patients, 24 rebounded and 16 were never suppressed, whereas among LPV/r patients, 33 rebounded and 26 were never suppressed. Transient HIV-1 RNA increases (≥ 50 copies/ml) occurred in 50% (n = 12) DRV/r and 48% (n = 16) LPV/r rebounders; these viral levels returned to undetectable by end point without any changes to the study regimen. No major (primary) protease inhibitor (PI) resistance-associated mutations (RAMs) developed in VFs with an available genotype at baseline and end point, and almost all developing minor PI RAMs were polymorphic. At end point, all VFs with available phenotypes at baseline and end point remained susceptible to all PIs, including study PIs. CONCLUSIONS: The VF rate was lower with DRV/r than LPV/r. The findings of this resistance analysis confirmed the lack of development of major PI RAMs and the preservation of phenotypic susceptibility to all PIs in patients with VF.

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 0.52 nM. Most (61%) patients in ARTEMIS harboured HIV-1 subtype B; other prevalent subtypes were C (13%) and CRF01_AE (17%); 9% harboured other subtypes. Median EC(50) values (interquartile range) for DRV were 1.79 nM (1.3-2.6) for subtype B, 1.12 nM (0.8-1.4) for C and 1.27 nM (1.0-1.7) for CRF01_AE. Virological response to DRV/r (HIV-1 RNA<50 copies/ml [intent-to-treat, time-to-loss of virological response algorithm]) was 81%, 87% and 85% for patients with subtype B, C and CRF01_AE infections, respectively. Similar results were observed in the LPV/r treatment group. CONCLUSIONS: In vitro susceptibility to DRV was comparable across HIV-1 subtypes in a broad panel of primary isolates and in recombinant clinical isolates. Once daily DRV/r 800/100 mg and LPV/r 800/200 mg were highly effective in ARTEMIS irrespective of the HIV-1 subtype studied, confirming their broad anti-HIV-1 activity.

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. Virologic failure by rebound occurred in 93 (15.5%) etravirine-treated patients (compared with 170 [28.1%] placebo-treated patients). Patients experiencing virologic failure had more baseline antiretroviral resistance and lower activity of the background regimen relative to those not experiencing failure. Emergence of NNRTI resistance-associated mutations was observed in 55 of 93 patients. The most frequently emerging RT mutations were V179F, V179I, and Y181C, with positions K101 and E138 also showing frequent changes. Mutations usually emerged in a background of multiple other NNRTI mutations and were, in most cases, associated with a decrease in phenotypic sensitivity to etravirine at endpoint. Further analysis is needed to clarify the role of mutations at position 138 as determinants of etravirine resistance.

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. Subgroup analyses from the DUET studies of the effect of HIV-1 subtype on the proportion of patients with viral load (VL) <50 HIV-1 RNA copies/ml were also conducted using pooled week 48 data. Genotype/subtype and phenotype determinations were performed using the vircoTYPE HIV-1 and Antivirogram assays, respectively. In vitro results from treatment-naive patients indicated comparable median ETR FC in virus isolates from patients infected with subtype B or non-B (1.1 vs. 1.2, respectively). HIV-1 subtype data were available for 594 and 595 patients in the ETR and placebo groups of the DUET studies, respectively; 94% of patients harbored subtype B. Baseline characteristics were similar across the different subtypes, with the exception of a higher number of sensitive NRTIs used in patients with subtype non-B. At week 48, virological responses in the ETR group were higher in patients with subtype non-B versus B (73% vs. 60%, respectively). ETR was equally effective in suppressing viral replication in patients infected with HIV-1 subtype B or various HIV-1 non-B subtypes.

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. METHODS: Week 24 data were pooled from the phase III studies with TMC125 to Demonstrate Undetectable viral load in patients Experienced with ARV Therapy (DUET). The effect of baseline resistance to etravirine on virologic response (<50 HIV-1 RNA copies/ml) was studied in patients not using de-novo enfuvirtide and excluding discontinuations for reasons other than virologic failure (n = 406). Clinical cutoffs for etravirine were established by analysis of covariance models and sliding fold change in 50% effective concentration (EC50) windows (Antivirogram; Virco BVBA, Mechelen, Belgium). Etravirine RAMs were identified as those associated with decreased virologic response/increased etravirine fold change in EC50. Relative weight factors were assigned to the etravirine RAMs using random forest and linear modeling techniques. RESULTS: Baseline etravirine fold change in EC50 predicted virologic response at week 24, with lower and preliminary upper clinical cutoffs of 3.0 and 13.0, respectively. A fold change in EC50 value above which etravirine provided little or no additional efficacy benefit could not be established. Seventeen etravirine RAMs were identified and attributed a relative weight factor accounting for the differential impact on etravirine fold change in EC50. Virologic response was a function of etravirine-weighted genotypic score. CONCLUSION: The weighted genotypic scoring algorithm optimizes resistance interpretations for etravirine and guides treatment decisions regarding its use in treatment-experienced patients.

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. A screening strategy used to test NNRTI candidates from the same series as etravirine identified TMC278 (rilpivirine). TMC278 is an NNRTI showing subnanomolar 50% effective concentrations (EC50 values) against wild-type HIV-1 group M isolates (0.07 to 1.01 nM) and nanomolar EC50 values against group O isolates (2.88 to 8.45 nM). Sensitivity to TMC278 was not affected by the presence of most single NNRTI resistance-associated mutations (RAMs), including those at positions 100, 103, 106, 138, 179, 188, 190, 221, 230, and 236. The HIV-1 site-directed mutant with Y181C was sensitive to TMC278, whereas that with K101P or Y181I/V was resistant. In vitro, considerable cross-resistance between TMC278 and etravirine was observed. Sensitivity to TMC278 was observed for 62% of efavirenz- and/or nevirapine-resistant HIV-1 recombinant clinical isolates. TMC278 inhibited viral replication at concentrations at which first-generation NNRTIs could not suppress replication. The rates of selection of TMC278-resistant strains were comparable among HIV-1 group M subtypes. NNRTI RAMs emerging in HIV-1 under selective pressure from TMC278 included combinations of V90I, L100I, K101E, V106A/I, V108I, E138G/K/Q/R, V179F/I, Y181C/I, V189I, G190E, H221Y, F227C, and M230I/L. E138R was identified as a new NNRTI RAM. These in vitro analyses demonstrate that TMC278 is a potent next-generation NNRTI, with a high genetic barrier to resistance development.

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. First generation NNRTIs nevirapine and efavirenz, in combination with other antiretroviral drugs, have become a cornerstone for the treatment of HIV-1 infection, in patients initiating antiretroviral therapy. Further research has led to the discovery and development of next generation NNRTIs with an increased genetic barrier to the development of resistance. Etravirine is the first NNRTI to show sustained virologic efficacy in patients with NNRTI resistant HIV-1. This review covers the NNRTI class of anti-HIV-1 drugs, from the initial discovery of the class in 1990 to the current compounds in clinical development, i.e. around 20 years of research and development efforts. It describes the characteristics of the NNRTIs, their mechanisms of action, HIV-1 resistance to the inhibitors, and the drugs that have been approved for the treatment of HIV-1 infection, or are currently in clinical development. The role of NNRTIs in prevention of HIV transmission is also addressed. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, vol. 85, issue 1, 2010.

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 0.6-50 nM against wild type HIV-1 and a panel of major simple/double HIV mutant strains.

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. The primary efficacy parameter was the change on day 8 in log(10) plasma VL from baseline. RESULTS: On day 8, median (min, max) changes from baseline in plasma VL were -0.87 (-2.3, 0.0), -0.95 (-1.8, 0.4) and -0.66 (-1.3, -0.2) log(10) copies/ml for the 25 mg, 50 mg and 150 mg once-daily TMC278 groups, respectively (P<0.001-<0.01). Overall, the median change from baseline was -1.19 log(10) copies/ml in the PI-substituted therapy group and -0.71 log(10) copies/ml in the NNRTI-substituted therapy group. TMC278 was generally safe and well tolerated with no apparent differences in safety among the three dose groups. CONCLUSIONS: Once-daily TMC278 showed significant antiviral activity against HIV-1 in treatment-experienced patients with NNRTI failure and/or resistance, and was generally safe and well tolerated.

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. METHODS: Patients received DRV/r 600/100 mg twice daily (n = 298) or LPV/r 400/100 mg twice daily (n = 297), and an optimized background regimen. Patients who lost or never achieved HIV-1 RNA less than 400 copies/ml after week 16 were considered virologic failure patients. Genotyping and phenotyping were performed. RESULTS: The virologic failure rate in the DRV/r arm (10%, n = 31) was lower than in the LPV/r arm (22%, n = 65). Furthermore, fewer virologic failure patients in the DRV/r arm than in the LPV/r arm developed primary protease inhibitor mutations (6 vs. 20) or nucleoside reverse transcriptase inhibitor resistance-associated mutations (4 vs. 15). In addition, fewer virologic failure patients on DRV/r than on LPV/r lost susceptibility to the protease inhibitor (3 vs. 13) or nucleoside reverse transcriptase inhibitor(s) (3 vs. 14) used in the treatment regimen or to other protease inhibitors. Most DRV/r-treated virologic failure patients retained susceptibility to all protease inhibitors. CONCLUSION: In treatment-experienced, LPV-naive patients, the overall virologic failure rate in the DRV/r arm was low and was associated with limited resistance development. These findings showed that the use of DRV/r in earlier lines of treatment was less likely to lead to cross-resistance to other protease inhibitors compared with LPV/r.

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. METHODS: We conducted an extensive review of the existing literature on NNRTI resistance, together with several in vitro and in vivo studies on the mechanism of HIV-1 resistance to approved NNRTIs and to NNRTIs formerly or currently in clinical development. RESULTS: In total, 44 NNRTI RAMs were identified. These included V90I, A98G, L100I, K1O1E/P/Q, K103H/N/S/T, V106A/I/M, V108I, E138G/K/Q, V179D/E/F/G/I, Y181C/I/V, Y188C/H/L, V189I, G190A/C/E/Q/S, H221Y, P225H, F227C/L, M230I/L, P236L, K238N/T and Y318F. These NNRTI RAMs were observed, either alone or in combination with others, ranging in frequency from 0.02% to 56.96% in a panel of 101,679 NNRTI-resistant isolates submitted to Virco BVBA (Mechelen, Belgium) for routine clinical resistance testing. Phenotypical data from site-directed mutants helped to establish the contribution of each mutation to NNRTI resistance. CONCLUSIONS: The list of 44 NNRTI RAMs compiled in this study provides a comprehensive overview of mutations that play a role in HIV-1 NNRTI resistance and can be used to guide further in vitro and in vivo research on the mechanisms of HIV-1 NNRTI resistance.

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). POWER 1 and 2 week 24 efficacy (intent-to-treat using time-to-loss of virologic response algorithm) data were pooled and analyzed according to baseline subgroups of susceptibility to the CPI regimen, fold-change (FC) in EC(50) to darunavir, and number of darunavir resistance-associated mutations (RAMs). In total, 131 patients received darunavir/r 600/100 mg twice daily; 124 received CPI(s) [lopinavir/r, 20%; saquinavir/r, 19%; (fos)-amprenavir/r, 24%; atazanavir/r, 11%; and 23% used dual-boosted CPI(s)]. At baseline, 72% of patients were resistant (defined as FC) to their investigator-selected CPIs. At week 24, darunavir/r 600/100 mg twice daily provided greater efficacy benefits over CPI(s), even when the virus was predicted to be fully susceptible to the CPI. The response to darunavir decreased when FC to darunavir at baseline was >40 or when three or more darunavir RAMs (in addition to other PI mutations) were present at baseline. Darunavir/r 600/100 mg twice daily showed efficacy benefits over CPI use regardless of viral susceptibility at baseline, FC to darunavir or boosting type in a population of treatment-experienced HIV-infected patients.

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. RESULTS: The proportion of patients achieving HIV RNA <50 copies per milliliter at week 24 was 67% for the group receiving darunavir/r 800/100 mg once daily and 62% for the group receiving darunavir/r 600/100 mg twice daily (P = 0.774); both were superior to control PI(s) (11%; P < 0.0001). Mean HIV RNA change from baseline was 22.39 and 22.35 log10 copies per milliliter for the group receiving darunavir/r 800/100 mg once daily and for the group receiving 600/100 mg twice daily, respectively (P = 0.895); mean CD4 increases were 88 and 111 cells per milliliter, respectively (P = 0.526). CONCLUSIONS: Treatment-experienced, HIV-infected patients with no baseline darunavir RAMs achieved similar high responses with darunavir/r 800/100 mg once daily and 600/100 mg twice daily. This suggests that once-daily darunavir/r 800/100 mg therapy, which has been shown effective in treatment-naive patients and is currently being studied in treatment-experienced patients, shows potential in patients with no darunavir RAMs.

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. Virological response to darunavir/r was maintained in the presence at baseline of a high number of IAS-USA PI resistance-associated mutations (IAS-USA PI RAMS); a diminished response occurred with >or=14. Eleven protease mutations associated with diminished darunavir/r virological response were identified (V11I, V32I, L33F, I47V, I50V, I54L/M, G73S, L76V, I84V, and L89V). These darunavir resistance-associated mutations (DRV RAMS) occurred in the presence of a high number of IAS-USA PI RAMS. Virological response was diminished with three or more DRV RAMS in the background of a high number of IAS-USA PI RAMS. Incremental numbers of DRV RAMS were more predictive of outcome than were IAS-USA PI RAMS. Mutations developing during darunavir/r virological failure (V32I, L33F, I47V, I54L, and L89V) were also featured in the DRV RAMS list. Site-directed mutants carrying these five mutations, or any one of these mutations either alone or together with one or two IAS-USA PI RAMS, showed no reduced darunavir susceptibility, suggesting that a high number of additional background mutations is required for darunavir resistance. In this population of treatment-experienced patients, darunavir/r demonstrated significantly greater efficacy than investigator-selected control PIs of trials POWER 1 and 2, regardless of baseline viral genotype or phenotype, while exhibiting a high genetic barrier to the development of resistance.

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. Debio-025 selectively inhibited the replication of HIV-1 in a CD4+ cell line and in peripheral blood mononuclear cells: potent activity was demonstrated against clinical isolates of various HIV-1 subtypes, including isolates with multidrug resistance to reverse transcriptase and protease inhibitors. Simian immunodeficiency virus and HIV-2 strains were generally resistant to inhibition by Debio-025; however, some notable exceptions of sensitive HIV-2 clinical isolates were detected. In two-drug combination studies, additive inhibitory effects were found between Debio-025 and 19 clinically used drugs of different classes. Clinical HIV-1 isolates that are naturally resistant to Debio-025 and that do not depend on CypA for infection were identified. Comparison of the amino acid sequences of the CypA binding domain of the capsid (CA) protein from Debio-025-sensitive and -resistant HIV-1 isolates indicated that resistance was mostly associated with an H87Q/P exchange. Mechanistically, cyclosporines competitively inhibit the binding of CypA to the HIV-1 CA protein, which is an essential interaction required for early steps in HIV-1 replication. By real-time PCR we demonstrated that early reverse transcription is reduced in the presence of Debio-025 and that late reverse transcription is almost completely blocked. Thus, Debio-025 seems to interfere with the function of CypA during the progression/completion of HIV-1 reverse transcription.

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. The primary endpoint was non-inferiority (95% CI lower limit for the difference in treatment response -12% or greater) for HIV RNA of less than 400 copies per mL in plasma at week 48 (per-protocol analysis). TITAN (TMC114-C214) is registered with ClinicalTrials.gov, number NCT00110877. FINDINGS: Of 595 patients randomised and treated, 187 (31%) were protease inhibitor naive; 476 of 582 (82%) were susceptible to four or more protease inhibitors. At week 48, significantly more darunavir-ritonavir than lopinavir-ritonavir patients had HIV RNA of less than 400 copies per mL (77% [220 of 286] vs 68% [199 of 293]; estimated difference 9%, 95% CI 2-16). Fewer virological failures treated with darunavir-ritonavir than with lopinavir-ritonavir developed primary protease inhibitor mutations (21% [n=6] vs 36% [n=20]) and nucleoside analogue-associated mutations (14% [n=4] vs 27% [n=15]). Safety data were generally similar between the groups; grade 3 or 4 adverse events occurred in 80 (27%) darunavir-ritonavir and 89 (30%) lopinavir-ritonavir patients. INTERPRETATION: In lopinavir-naive, treatment-experienced patients, darunavir-ritonavir was non-inferior to lopinavir-ritonavir treatment in terms of our virological endpoint, and should therefore be considered as a treatment option for this population.

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. Most evidence points to transepithelial migration of virus, released from HIV-PBMCs after their activation by epithelial cells. We used this model for evaluation of the therapeutic index of various potentially preventive antiviral compounds, including non-nucleoside reverse transcriptase inhibitors (NNRTIs, including UC781 and various diaryltriazines and diarylpyrimidines), poly-anionic entry inhibitors (including PRO2000, cellulose sulphate, dextrane sulphate 5000 and polystyrene sulphonate) and the fusion inhibitor T-20. The epithelium was pre-treated with compound and incubated with HIV-PBMCs for 24 h. Afterwards the apical chamber was removed and MO-DC/CD4(+) T cell co-cultures were further cultured without compound. NNRTIs, including a TMC120 gel, blocked infection of the sub-epithelial targets at sub-micromolar concentrations. Polyanionic entry inhibitors (up to 100 microg/ml) and T-20 (up to 449 microg/ml) failed to inhibit transmission. Moreover, whereas the NNRTIs used interfered with epithelial integrity with cervical epithelium only at very high concentrations, the evaluated entry inhibitors showed toxicity at concentrations that did not prevent infection.