Showing papers on "Dolutegravir published in 2015"

Brief Report: Dolutegravir Plus Abacavir/Lamivudine for the Treatment of HIV-1 Infection in Antiretroviral Therapy-Naive Patients: Week 96 and Week 144 Results From the SINGLE Randomized Clinical Trial.

Abstract: The SINGLE study was a randomized, double-blind, noninferiority study that evaluated the safety and efficacy of 50 mg dolutegravir + abacavir/lamivudine versus efavirenz/tenofovir/emtricitabine in 833 ART-naive HIV-1 + participants. Of 833 randomized participants, 71% in the dolutegravir + abacavir/lamivudine arm and 63% in the efavirenz/tenofovir/emtricitabine arm maintained viral loads of <50 copies per milliliter through W144 (P = 0.01). Superior efficacy was primarily driven by fewer discontinuations due to adverse events in the dolutegravir + abacavir/lamivudine arm [dolutegravir + abacavir/lamivudine arm, 16 (4%); efavirenz/tenofovir/emtricitabine arm, 58 (14%)] through W144 [corrected]. No treatment-emergent integrase or nucleoside resistance was observed in dolutegravir + abacavir/lamivudine recipients through W144.

Genetic barrier to resistance for dolutegravir.

Abstract: Dolutegravir is a novel integrase strand-transfer inhibitor that displays potent in vitro activity and a remarkably different resistance profile. Its robust pharmacokinetic/pharmacodynamic properties - long plasma t1/2, high plasma inhibition quotient, and slow dissociation rate from the integrase complex - suggest it should present a high barrier to resistance development. This has been confirmed in pivotal phase III studies of initial therapy, with none out of 1,118 treated individuals selecting resistance-associated mutations at the integrase or reverse transcriptase. In integrase-naive subjects with virological failure, a rescue intervention with dolutegravir has shown significantly higher rates of virological suppression than raltegravir, as well as significantly lower rates of selection of resistance both at the integrase and against the optimized background. Unexpectedly, a mutation rarely selected in this scenario (R263K) induces a fitness cost that prevents HIV-1 from evading drug pressure, and accumulation of further secondary mutations does not occur and has not been able to compensate the replication capacity deficit in the aftermath of the appearance of a single drug resistance mutation. Therefore, both in vitro and in vivo, it leads the virus to a previously unnoticed evolutionary pathway with low chances to develop resistance to both dolutegravir and other families of antiretrovirals present in the background. This high genetic barrier to resistance development in early stages of antiretroviral treatment can help preserve future treatment options in patients who fail antiretroviral therapy.

Pharmacokinetics of Dolutegravir When Administered With Mineral Supplements in Healthy Adult Subjects

Abstract: All commercially available integrase inhibitors are 2-metal binders and may be affected by co-administration with metal cations. The purpose of this study was to evaluate the effect of calcium and iron supplements on dolutegravir pharmacokinetics and strategies (dose separation and food) to attenuate the effects if significant reductions in dolutegravir exposure were observed. This was an open-label, crossover study that randomized 24 healthy subjects into 1 of 2 cohorts to receive 4 treatments: (1) dolutegravir alone, fasting; (2) dolutegravir with calcium carbonate or ferrous fumarate, fasting; (3) dolutegravir with calcium carbonate or ferrous fumarate with a moderate-fat meal; (4) dolutegravir administered 2 hours before calcium carbonate or ferrous fumarate, fasting. Plasma dolutegravir AUC(0–∞), Cmax, and C24 were reduced by 39%, 37%, and 39%, respectively, when co-administered with calcium carbonate while fasting and were reduced by 54%, 57%, and 56%, respectively, when co-administered with ferrous fumarate while fasting. Dolutegravir administration 2 hours before calcium or iron supplement administration (fasted), as well as administration with a meal, counteracted the effect. Dolutegravir and calcium or iron supplements can be co-administered if taken with a meal. Under fasted conditions, dolutegravir should be administered 2 hours before or 6 hours after calcium or iron supplements.

Dolutegravir - a review of the pharmacology, efficacy, and safety in the treatment of HIV.

Abstract: Dolutegravir is the newest integrase strand transfer inhibitor to be approved for the treatment of human immunodeficiency virus (HIV) infection. Dolutegravir is equivalent or superior to existing treatment regimens in both treatment-naive and treatment-experienced patients including those with previous raltegravir or elvitegravir failure. The consistent efficacy coupled with excellent tolerability and infrequent drug-drug interactions makes the co-formulation of dolutegravir with two nucleotide reverse-transcriptase inhibitors an attractive treatment option. This review summarizes the pharmacokinetics, adverse event profile, and efficacy of dolutegravir in the treatment of HIV.

Antiviral Characteristics of GSK1265744, an HIV Integrase Inhibitor Dosed Orally or by Long-Acting Injection

Abstract: GSK1265744 is a new HIV integrase strand transfer inhibitor (INSTI) engineered to deliver efficient antiviral activity with a once-daily, low-milligram dose that does not require a pharmacokinetic booster. The in vitro antiviral profile and mechanism of action of GSK1265744 were established through integrase enzyme assays, resistance passage experiments, and cellular assays with site-directed molecular (SDM) HIV clones resistant to other classes of anti-HIV-1 agents and earlier INSTIs. GSK1265744 inhibited HIV replication with low or subnanomolar efficacy and with a selectivity index of at least 22,000 under the same culture conditions. The protein-adjusted half-maximal inhibitory concentration (PA-EC50) extrapolated to 100% human serum was 102 nM. When the virus was passaged in the presence of GSK1265744, highly resistant mutants with more than a 10-fold change (FC) in EC50 relative to that of the wild-type were not observed for up to 112 days of culture. GSK1265744 demonstrated activity against SDM clones containing the raltegravir (RAL)-resistant Y143R, Q148K, N155H, and G140S/Q148H signature variants (FC less than 6.1), while these mutants had a high FC in the EC50 for RAL (11 to >130). Either additive or synergistic effects were observed when GSK1265744 was tested in combination with representative anti-HIV agents, and no antagonistic effects were seen. These findings demonstrate that, similar to dolutegravir, GSK1265744 is differentiated as a new INSTI, having a markedly distinct resistance profile compared with earlier INSTIs, RAL, and elvitegravir (EVG). The collective data set supports further clinical development of GSK1265744.

Integrase inhibitor (INI) genotypic resistance in treatment-naive and raltegravir-experienced patients infected with diverse HIV-1 clades

Abstract: OBJECTIVES The aim of this study was to characterize the prevalence and patterns of genotypic integrase inhibitor (INI) resistance in relation to HIV-1 clade. METHODS The cohort comprised 533 INI-naive subjects and 255 raltegravir recipients with viraemia who underwent integrase sequencing in routine care across Europe, including 134/533 (25.1%) and 46/255 (18.0%), respectively, with non-B clades (A, C, D, F, G, CRF01, CRF02, other CRFs, complex). RESULTS No major INI resistance-associated mutations (RAMs) occurred in INI-naive subjects. Among raltegravir recipients with viraemia (median 3523 HIV-1 RNA copies/mL), 113/255 (44.3%) had one or more major INI RAMs, most commonly N155H (45/255, 17.6%), Q148H/R/K + G140S/A (35/255, 13.7%) and Y143R/C/H (12/255, 4.7%). In addition, four (1.6%) raltegravir recipients showed novel mutations at recognized resistance sites (E92A, S147I, N155D, N155Q) and novel mutations at other integrase positions that were statistically associated with raltegravir exposure (K159Q/R, I161L/M/T/V, E170A/G). Comparing subtype B with non-B clades, Q148H/R/K occurred in 42/209 (20.1%) versus 2/46 (4.3%) subjects (P = 0.009) and G140S/A occurred in 36/209 (17.2%) versus 1/46 (2.2%) subjects (P = 0.005). Intermediate- to high-level cross-resistance to twice-daily dolutegravir was predicted in 40/255 (15.7%) subjects, more commonly in subtype B versus non-B clades (39/209, 18.7% versus 1/46, 2.2%; P = 0.003). A glycine (G) to serine (S) substitution at integrase position 140 required one nucleotide change in subtype B and two nucleotide changes in all non-B clades. CONCLUSIONS No major INI resistance mutations occurred in INI-naive subjects. Reduced occurrence of Q148H/R/K + G140S/A was seen in non-B clades versus subtype B, and was explained by the higher genetic barrier to the G140S mutation observed in all non-B clades analysed.

Primary resistance to integrase strand-transfer inhibitors in Europe.

Abstract: Objectives: The objective of this study was to define the natural genotypic variation of the HIV-1 integrase gene across Europe for epidemiological surveillance of integrase strand-transfer inhibitor (InSTI) resistance. Methods: This was a multicentre, cross-sectional study within the European SPREAD HIV resistance surveillance programme. A representative set of 300 samples was selected from 1950 naive HIV-positive subjects newly diagnosed in 2006-07. The prevalence of InSTI resistance was evaluated using quality-controlled baseline population sequencing of integrase. Signature raltegravir, elvitegravir and dolutegravir resistance mutations were defined according to the IAS-USA 2014 list. In addition, all integrase substitutions relative to HXB2 were identified, including those with a Stanford HIVdb score >= 10 to at least one InSTI. To rule out circulation of minority InSTI-resistant HIV, 65 samples were selected for 454 integrase sequencing. Results: For the population sequencing analysis, 278 samples were retrieved and successfully analysed. No signature resistance mutations to any of the InSTIs were detected. Eleven (4%) subjects had mutations at resistance-associated positions with an HIVdb score >= 10. Of the 56 samples successfully analysed with 454 sequencing, no InSTI signature mutations were detected, whereas integrase substitutions with an HIVdb score >= 10 were found in 8 (14.3%) individuals. Conclusions: No signature InSTI-resistant variants were circulating in Europe before the introduction of InSTIs. However, polymorphisms contributing to InSTI resistance were not rare. As InSTI use becomes more widespread, continuous surveillance of primary InSTI resistance is warranted. These data will be key to modelling the kinetics of InSTI resistance transmission in Europe in the coming years.

Comparative Changes of Lipid Levels in Treatment-Naive, HIV-1-Infected Adults Treated with Dolutegravir vs. Efavirenz, Raltegravir, and Ritonavir-Boosted Darunavir-Based Regimens Over 48 Weeks

Abstract: Background and Objectives Long-term use of antiretroviral therapy (ART) to treat HIV infection has been associated with dyslipidemia and metabolic and cardiovascular complications. Available options for patients at risk of cardiovascular disease include antiretroviral drugs with improved lipid profiles. Dolutegravir is one of a new generation of HIV integrase inhibitors recently incorporated into the US Department of Health and Human Services, German, Spanish, and Italian HIV treatment guidelines as a preferred first-line third agent in combination with dual nucleoside reverse transcriptase inhibitor (NRTI) backbone therapies. To understand the lipid profile of dolutegravir in the context of combination ART, we analyzed the lipid outcomes at 48 weeks in ART-naive participants in four phase IIb–IIIb clinical trials.

Differential Effects of the G118R, H51Y, and E138K Resistance Substitutions in Different Subtypes of HIV Integrase

Abstract: Dolutegravir (DTG) is the latest antiretroviral (ARV) approved for the treatment of human immunodeficiency virus (HIV) infection. The G118R substitution, previously identified with MK-2048 and raltegravir, may represent the initial substitution in a dolutegravir resistance pathway. We have found that subtype C integrase proteins have a low enzymatic cost associated with the G118R substitution, mostly at the strand transfer step of integration, compared to either subtype B or recombinant CRF02_AG proteins. Subtype B and circulating recombinant form AG (CRF02_AG) clonal viruses encoding G118R-bearing integrases were severely restricted in their viral replication capacity, and G118R/E138K-bearing viruses had various levels of resistance to dolutegravir, raltegravir, and elvitegravir. In cell-free experiments, the impacts of the H51Y and E138K substitutions on resistance and enzyme efficiency, when present with G118R, were highly dependent on viral subtype. Sequence alignment and homology modeling showed that the subtype-specific effects of these mutations were likely due to differential amino acid residue networks in the different integrase proteins, caused by polymorphic residues, which significantly affect native protein activity, structure, or function and are important for drug-mediated inhibition of enzyme activity. This preemptive study will aid in the interpretation of resistance patterns in dolutegravir-treated patients. IMPORTANCE Recognized drug resistance mutations have never been reported for naive patients treated with dolutegravir. Additionally, in integrase inhibitor-experienced patients, only R263K and other previously known integrase resistance substitutions have been reported. Here we suggest that alternate resistance pathways may develop in non-B HIV-1 subtypes and explain how “minor” polymorphisms and substitutions in HIV integrase that are associated with these subtypes can influence resistance against dolutegravir. This work also highlights the importance of phenotyping versus genotyping when a strong inhibitor such as dolutegravir is being used. By characterizing the G118R substitution, this work also preemptively defines parameters for a potentially important pathway in some non-B HIV subtype viruses treated with dolutegravir and will aid in the inhibition of such a virus, if detected. The general inability of strand transfer-related substitutions to diminish 3′ processing indicates the importance of the 3′ processing step and highlights a therapeutic angle that needs to be better exploited.

HIV integrase inhibitors: a new era in the treatment of HIV.

Abstract: Introduction: Integrase inhibitors (INIs) are the latest class of antiretroviral drugs approved for the treatment of HIV infection and are becoming ‘standard’ drugs in the treatment of both naive as well as heavily pretreated individuals with HIV.Areas covered: Data on efficacy, safety, tolerability, pharmacokinetics, drug-drug interactions and resistance are reviewed from the pivotal Phase III clinical trials published in PubMed high-impact medical journals or presented at international meetings.Expert opinion: Due to their outstanding data of efficacy, tolerability, safety – shared by all three drugs (raltegravir, elvitegravir, dolutegravir) currently belonging to this new family of antiretrovirals – INIs have become part of the recommended initial antiretroviral therapy options. Some differences in dosing, drug-drug interactions and robustness/genetic barrier among the three drugs will provide the physician the characteristics to make the best choice.

Cross-resistance to elvitegravir and dolutegravir in 502 patients failing on raltegravir: a French national study of raltegravir-experienced HIV-1-infected patients

Abstract: Author(s): Fourati, Slim; Charpentier, Charlotte; Amiel, Corinne; Morand-Joubert, Laurence; Reigadas, Sandrine; Trabaud, Mary-Anne; Delaugerre, Constance; Nicot, Florence; Rodallec, Audrey; Maillard, Anne; Mirand, Audrey; Jeulin, Helene; Montes, Brigitte; Barin, Francis; Bettinger, Dominique; Le Guillou-Guillemette, Helene; Vallet, Sophie; Signori-Schmuck, Anne; Descamps, Diane; Calvez, Vincent; Flandre, Philippe; Marcelin, Anne-Genevieve; ANRS AC11 Resistance Study Group | Abstract: ObjectivesThe objectives of this study were to determine the prevalence and patterns of resistance to integrase strand transfer inhibitors (INSTIs) in patients experiencing virological failure on raltegravir-based ART and the impact on susceptibility to INSTIs (raltegravir, elvitegravir and dolutegravir).Patients and methodsData were collected from 502 treatment-experienced patients failing a raltegravir-containing regimen in a multicentre study. Reverse transcriptase, protease and integrase were sequenced at failure for each patient. INSTI resistance-associated mutations investigated were those included in the last ANRS genotypic algorithm (v23).ResultsAmong the 502 patients, at failure, median baseline HIV-1 RNA (viral load) was 2.9 log10 copies/mL. Patients had been previously exposed to a median of five NRTIs, one NNRTI and three PIs. Seventy-one percent harboured HIV-1 subtype B and the most frequent non-B subtype was CRF02_AG (13.3%). The most frequent mutations observed were N155H/S (19.1%), Q148G/H/K/R (15.4%) and Y143C/G/H/R/S (6.7%). At failure, viruses were considered as fully susceptible to all INSTIs in 61.0% of cases, whilst 38.6% were considered as resistant to raltegravir, 34.9% to elvitegravir and 13.9% to dolutegravir. In the case of resistance to raltegravir, viruses were considered as susceptible to elvitegravir in 11% and to dolutegravir in 64% of cases. High HIV-1 viral load at failure (P l 0.001) and low genotypic sensitivity score of the associated treatment with raltegravir (P l 0.001) were associated with the presence of raltegravir-associated mutations at failure. Q148 mutations were selected more frequently in B subtypes versus non-B subtypes (P = 0.004).ConclusionsThis study shows that a high proportion of viruses remain susceptible to dolutegravir in the case of failure on a raltegravir-containing regimen.

Resistance against Integrase Strand Transfer Inhibitors and Relevance to HIV Persistence

Abstract: Drug resistance prevents the successful treatment of HIV-positive individuals by decreasing viral sensitivity to a drug or a class of drugs. In addition to transmitted resistant viruses, treatment-naive individuals can be confronted with the problem of drug resistance through de novo emergence of such variants. Resistant viruses have been reported for every antiretroviral drug tested so far, including the integrase strand transfer inhibitors raltegravir, elvitegravir and dolutegravir. However, de novo resistant variants against dolutegravir have been found in treatment-experienced but not in treatment-naive individuals, a characteristic that is unique amongst antiretroviral drugs. We review here the issue of drug resistance against integrase strand transfer inhibitors as well as both pre-clinical and clinical studies that have led to the identification of the R263K mutation in integrase as a signature resistance substitution for dolutegravir. We also discuss how the topic of drug resistance against integrase strand transfer inhibitors may have relevance in regard to the nature of the HIV reservoir and possible HIV curative strategies.

Dolutegravir efficacy at 48 weeks in key subgroups of treatment-naive HIV-infected individuals in three randomized trials

Abstract: Objectives Dolutegravir (DTG) has been studied in three trials in HIV treatment-naive participants, showing noninferiority compared with raltegravir (RAL), and superiority compared with efavirenz and ritonavir-boosted darunavir. We explored factors that predicted treatment success, the consistency of observed treatment differences across subgroups and the impact of NRTI backbone on treatment outcome. Design Retrospective exploratory analyses of data from three large, randomized, international comparative trials: SPRING-2, SINGLE, and FLAMINGO. Methods We examined the efficacy of DTG in HIV-infected participants with respect to relevant demographic and HIV-1-related baseline characteristics using the primary efficacy endpoint from the studies (FDA snapshot) and secondary endpoints that examine specific elements of treatment response. Regression models were used to analyze pooled data from all three studies. Results Snapshot response was affected by age, hepatitis co-infection, HIV risk factor, baseline CD4⁺ cell count, and HIV-1 RNA and by third agent. Differences between DTG and other third agents were generally consistent across these subgroups. There was no evidence of a difference in snapshot response between abacavir/lamivudine (ABC/3TC) and tenofovir/emtricitabine (TDF/FTC) overall [ABC/3TC 86%, TDF/FTC 85%, difference 1.1%, confidence interval (CI) -1.8, 4.0 percentage points, P = 0.61] or at high viral loads (difference -2.5, 95% CI -8.9, 3.8 percentage points, P = 0.42). Conclusions DTG is a once-daily, unboosted integrase inhibitor that is effective in combination with either ABC/3TC or TDF/FTC for first-line antiretroviral therapy in HIV-positive individuals with a variety of baseline characteristics.

Population pharmacokinetics of dolutegravir in HIV-infected treatment-naive patients.

Abstract: Aim Dolutegravir is the newest integrase inhibitor approved for HIV treatment and has demonstrated potent antiviral activity in patient populations with a broad range of treatment experience. This analysis aimed to characterize the population pharmacokinetics of dolutegravir in treatment-naive patients and to evaluate the influence of patient covariates. Methods A population pharmacokinetic model was developed using a non-linear mixed effect modelling approach based on data from 563 HIV-infected, treatment-naive adult patients in three phase 2/3 trials who received dolutegravir (ranging from 10–50 mg once daily) alone or in combination with abacavir/lamivudine or tenofovir/emtricitabine. Results The pharmacokinetics of dolutegravir were adequately described by a linear one compartment model with first order absorption, absorption lag time and first order elimination. Population estimates for apparent clearance, apparent volume of distribution, absorption rate constant and absorption lag time were 0.901 l h–1, 17.4 l, 2.24 h−1, and 0.263 h, respectively. Weight, smoking status, age and total bilirubin were predictors of clearance, weight was a predictor of volume of distribution and gender was a predictor of bioavailability. However, the magnitude of the effects of these covariates on steady-state dolutegravir plasma exposure was relatively small (<32%) and was not considered clinically significant. Race/ethnicity, HBV/HCV co-infection, CDC classification, albumin, creatinine clearance, alanine aminotransferase or aspartate aminotransferase did not influence the pharmacokinetics of dolutegravir in this analysis. Conclusions A population model that adequately characterizes dolutegravir pharmacokinetics has been developed. No dolutegravir dose adjustment by patient covariates is necessary in HIV-infected treatment-naive patients.

Safety, Pharmacokinetics and Efficacy of Dolutegravir in Treatment-experienced HIV-1 Infected Adolescents: Forty-eight-week Results from IMPAACT P1093.

Abstract: To assess the pharmacokinetics (PK), safety and efficacy of dolutegravir plus optimized background regimen in HIV-infected treatment-experienced adolescents.Children older than 12 to younger than 18 years received dolutegravir weight-based fixed doses at approximately 1.0 mg/kg once daily in a phase I/II multicenter open label 48-week study. Intensive PK evaluation was done at steady state after dolutegravir was added to a failing regimen or started at the end of a treatment interruption. Safety and HIV RNA and CD4 cell count assessments were performed through week 48.Twenty-three adolescents were enrolled and 22 (96%) completed the 48-week study visit. Median age and weight were 15 years and 52 kg, respectively. Median [interquartile range (IQR)] baseline CD4+ cell count was 466 cells/μL (297, 771). Median (IQR) baseline HIV-1 RNA log10 was 4.3 log10 copies/mL (3.9, 4.6). Dolutegravir geometric mean of the area under the plasma concentration-time curve from time of administration to 24 hours after dosing (AUC0-24) and 24 hour postdose concentration (C24) were 46.0 μg hours/mL and 0.90 μg/mL, respectively, which were within the study targets based on adult PK ranges. Virologic success with an HIV RNA <400 copies/mL was achieved in 74% [95% confidence interval (CI): 52-90%] at week 48. Additionally, 61% (95% CI: 39-80%) had an HIV RNA <50 copies/mL at week 48. Median (IQR) gain in CD4 cell count at week 48 was 84 cells/μL (-81, 238). Dolutegravir was well tolerated, with no grade 4 adverse events, serious adverse events or discontinuations because of serious adverse events.Dolutegravir achieved target PK exposures in adolescents. Dolutegravir was safe and well tolerated, providing good virologic efficacy through week 48.

Pharmacokinetic and Pharmacodynamic Drug Interactions Between Antiretrovirals and Oral Contraceptives

Abstract: More than 50 % of women living with HIV in low- and middle-income countries are of reproductive age, but there are limitations to the administration of oral contraception for HIV-infected women receiving antiretroviral therapy due to drug–drug interactions caused by metabolism via the cytochrome P450 isoenzymes and glucuronidation. However, with the development of newer antiretrovirals that use alternative metabolic pathways, options for contraception in HIV-positive women are increasing. This paper aims to review the literature on the pharmacokinetics and pharmacodynamics of oral hormonal contraceptives when given with antiretroviral agents, including those currently used in developed countries, older ones that might still be used in salvage regimens, or those used in resource-limited settings, as well as newer drugs. Nucleos(t)ide reverse transcriptase inhibitors (NRTIs), the usual backbone to most combined antiretroviral treatments (cARTs) are characterised by a low potential for drug–drug interactions with oral contraceptives. On the other hand non-NRTIs (NNRTIs) and protease inhibitors (PIs) may interact with oral contraceptives. Of the NNRTIs, efavirenz and nevirapine have been demonstrated to cause drug–drug interactions; however, etravirine and rilpivirine appear safe to use without dose adjustment. PIs boosted with ritonavir are not recommended to be used with oral contraceptives, with the exception of boosted atazanavir which should be used with doses of at least 35 µg of estrogen. Maraviroc, an entry inhibitor, is safe for co-administration with oral contraceptives, as are the integrase inhibitors (INIs) raltegravir and dolutegravir. However, the INI elvitegravir, which is given in combination with cobicistat, requires a dose of estrogen of at least 30 µg. Despite the growing evidence in this field, data are still lacking in terms of large cohort studies, randomised trials and correlations to real clinical outcomes, such as pregnancy rates, in women on antiretrovirals and hormonal contraception.

Dolutegravir in HIV-2–Infected Patients With Resistant Virus to First-line Integrase Inhibitors From the French Named Patient Program

Abstract: BACKGROUND Dolutegravir has shown in vitro activity against human immunodeficiency virus type 2 (HIV-2). We report safety and efficacy data of regimens containing dolutegravir (50 mg twice daily) in antiretroviral-experienced, HIV-2-infected patients. METHODS HIV-2-infected patients experiencing virological failure to raltegravir received dolutegravir with optimized background antiretroviral combinations within the French Named Patient Program (NPP). Plasma HIV-2 RNA (pVL) was assessed at time of dolutegravir initiation (baseline), month 3, and month 6. Antiretroviral trough plasma concentrations (C12h) were determined using liquid chromatography coupled with tandem mass spectrometry. RESULTS Thirteen HIV-2-infected-patients, with a median duration of 15 years' infection and given 16 previous antiretroviral regimens, were included in NPP. Median follow-up was 9 months (min-max, 3-15 months). Median baseline pVL and CD4 cell count were 9544 copies/mL (inter quartile range [IQR], 3096-23 120 copies/mL) and 100 cells/µL (IQR, 77-171 cells/µL), respectively. Available integrase genotypic resistance patterns were Y143C/G/H/R (n = 5), Q148R/K (n = 2), and N155H (n = 4). Optimized background antiretroviral regimens conferring a genotypic sensitivity score ≤2 in 10 patients included nucleoside reverse transcriptase inhibitors associated with darunavir/ritonavir (n = 12), saquinavir/ritonavir (n = 2), and maraviroc (n = 3). At months 3 and 6, pVL was undetectable in 6 of 13 and 4 of 12 patients, respectively, and median CD4 count was 161 (101-188) cells/µL and 167 (135-1353) cells/µL, respectively. Median dolutegravir C12h was 4086 (1756-5717 ng/mL) ng/mL in 9 patients. No serious events were notified except 1 death from progressive multifocal leukoencephalopathy at month 4. CONCLUSIONS Optimized dolutegravir-containing antiretroviral regimens supported by good plasma exposure provide a substantial initial efficacy rate for salvage therapy in heavily antiretroviral-experienced HIV-2-infected patients with virus harboring resistance to first-generation integrase inhibitors. Larger numbers of patients and longer follow-up are needed to confirm these findings.

Abacavir/dolutegravir/lamivudine single-tablet regimen: a review of its use in HIV-1 infection.

Abstract: A fixed-dose, single-tablet regimen comprising the integrase strand transfer inhibitor (INSTI) dolutegravir and the nucleos(t)ide reverse transcriptase inhibitors (NRTIs) abacavir and lamivudine (abacavir/dolutegravir/lamivudine; Triumeq®) is now available for the treatment of HIV-1 infection. In a randomized, double-blind, phase III trial in antiretroviral therapy (ART)-naive adults (SINGLE), once-daily dolutegravir plus abacavir/lamivudine had noninferior efficacy to once-daily efavirenz/tenofovir disoproxil fumarate (tenofovir DF)/emtricitabine with regard to establishing and sustaining virological suppression over 144 weeks, and subsequent superiority testing significantly favoured dolutegravir plus abacavir/lamivudine. This outcome was predominantly driven by more favourable rates of discontinuation due to adverse events versus the efavirenz/tenofovir DF/emtricitabine group. These data were generally supported by findings from other phase III trials in ART-naive adults receiving dolutegravir plus either abacavir/lamivudine or tenofovir DF/emtricitabine (SPRING-2 and FLAMINGO). Dolutegravir plus abacavir/lamivudine is generally well tolerated, with a tolerability profile that appears to be more favourable than efavirenz/tenofovir DF/emtricitabine. In the SINGLE trial, there were no major treatment-emergent INSTI or NRTI resistance-associated mutations in dolutegravir plus abacavir/lamivudine recipients with protocol-defined virological failure, indicating a high genetic barrier to resistance. Thus, triple combination therapy with abacavir, dolutegravir and lamivudine is an effective, generally well tolerated option for the management of HIV-1 infection, with the convenient once-daily fixed-dose tablet providing the first single-tablet regimen option without tenofovir DF.

Review of integrase strand transfer inhibitors for the treatment of human immunodeficiency virus infection.

Abstract: Integrase strand transfer inhibitors (INSTIs) are oral antiretroviral agents used against HIV infection. There are three agents available, including raltegravir, elvitegravir and dolutegravir, some of which are available as combination medications with other antiretroviral drugs. The efficacy and safety of INSTIs in treatment-naive and experienced HIV-infected patients have been established by multiple studies. Based on the current practice guidelines, INSTI-based regimens are considered as one of the first-line therapies for treatment-naive HIV-infected patients. There are new INSTIs in development to improve the resistance profile and to decrease the frequency of drug administration.

Clinical effectiveness of dolutegravir in the treatment of HIV/AIDS

Abstract: Dolutegravir (DTG) is a second-generation integrase strand transfer inhibitor (INSTI), which has now been licensed to be used in different countries including the UK. Earlier studies have demonstrated that DTG when used with nucleoside backbone in treatment-naive and - experienced patients has been well tolerated and demonstrated virological suppression comparable to other INSTIs and superiority against other first-line agents, including efavirenz and boosted protease inhibitors. Like other INSTIs, DTG uses separate metabolic pathways compared to other antiretrovirals and is a minor substrate for CYP-450. It does not appear to have a significant interaction with drugs, which uses the CYP-450 system. Nonetheless, it uses renal solute transporters that may potentially inhibit the transport of other drugs and can have an effect on the elimination of other drugs. However, the impact of this mechanism appears to be very minimal and insignificant clinically. The side effect profiles of DTG are similar to raltegravir and have been found to be well tolerated. DTG has a long plasma half-life and is suitable for once daily use without the need for a boosting agent. DTG has all the potential to be used as a first-line drug in combination with other nucleoside backbones, especially in the form of a single tablet in combination with abacavir and lamivudine. The purpose of this review article is to present the summary of the available key information about the clinical usefulness of DTG in the treatment of HIV infection.

Psychiatric disorders after starting dolutegravir: report of four cases.

Abstract: Treatment of HIV-infected individuals as a way of preventing further infections has so far had limited impact on the incidence of new infections in a population, mainly because of the low percentage of infected persons receiving adequate ART [1–3]. This is because of either individuals being unaware of their infection or ART being withheld until a critical CD4þ level is reached. The ‘Venhälsan’ clinic was established in 1982 at Stockholm South General Hospital (Södersjukhuset), an inner city hospital with 110 000 emergency department annual visits, to combat sexually transmitted infections (STIs) among MSM in a nonjudgmental setting. ‘Venhälsan’ annually offers STItesting and rapid HIV-testing to about 6000 MSM.

Evolution of a novel pathway leading to dolutegravir resistance in a patient harbouring N155H and multiclass drug resistance

Abstract: Received 29 July 2014; returned 14 August 2014; revised 2 September 2014; accepted 3 September 2014Objectives: Dolutegravir has been recently approved for treatment-naive and -experienced HIV-infected sub-jects, including integrase inhibitor (INI)-experienced patients. Dolutegravir is a second-generation INI that canovercome many prior raltegravir and elvitegravir failures. Here, we report the evolution of resistance to dolute-gravir in a highly treatment-experienced patientharbouring the major N155H mutation consequent to raltegravirtreatment failure.Methods:Genotypic and phenotypic analyses were done on longitudinal samplesto determine viral resistance toINIs. Integrase amino acid sequence interactions with raltegravir and dolutegravir were assessed by molecularmodelling and docking simulations.Results: Five mutations (A49P, L68FL, T97A, E138K and L234V) were implicated in emergent dolutegravir resist-ance, with a concomitant severe compromise inviral replicative capacity. Molecular modelling and docking simu-lations revealed that dolutegravir binding to integrase was affected by these acquired dolutegravir mutations.Conclusions: Our findings identify a novel mutational pathway involving integrase mutations A49P and L234V,leading to dolutegravir resistance in a patient with the N155H raltegravir mutation.Keywords: HIV-1, integrase inhibitors, mutations, phenotype, genotype

In vitro activity of dolutegravir against wild-type and integrase inhibitor-resistant HIV-2.

Abstract: Dolutegravir recently became the third integrase strand transfer inhibitor (INSTI) approved for use in HIV-1–infected individuals. In contrast to the extensive dataset for HIV-1, in vitro studies and clinical reports of dolutegravir for HIV-2 are limited. To evaluate the potential role of dolutegravir in HIV-2 treatment, we compared the susceptibilities of wild-type and INSTI-resistant HIV-1 and HIV-2 strains to the drug using single-cycle assays, spreading infections of immortalized T cells, and site-directed mutagenesis. HIV-2 group A, HIV-2 group B, and HIV-1 isolates from INSTI-naive individuals were comparably sensitive to dolutegravir in the single-cycle assay (mean EC50 values = 1.9, 2.6, and 1.3 nM, respectively). Integrase substitutions E92Q, Y143C, E92Q + Y143C, and Q148R conferred relatively low levels of resistance to dolutegravir in HIV-2ROD9 (2- to 6-fold), but Q148K, E92Q + N155H, T97A + N155H and G140S + Q148R resulted in moderate resistance (10- to 46-fold), and the combination of T97A + Y143C in HIV-2ROD9 conferred high-level resistance (>5000-fold). In contrast, HIV-1NL4-3 mutants E92Q + N155H, G140S + Q148R, and T97A + Y143C showed 2-fold, 4-fold, and no increase in EC50, respectively, relative to the parental strain. The resistance phenotypes for E92Q + N155H, and G140S + Q148R HIV-2ROD9 were also confirmed in spreading infections of CEM-ss cells. Our data support the use of dolutegravir in INSTI-naive HIV-2 patients but suggest that, relative to HIV-1, a broader array of replacements in HIV-2 integrase may enable cross-resistance between dolutegravir and other INSTI. Clinical studies are needed to evaluate the efficacy of dolutegravir in HIV-2–infected individuals, including patients previously treated with raltegravir or elvitegravir.

Will drug resistance against dolutegravir in initial therapy ever occur

Abstract: Dolutegravir (DTG) is a second-generation integrase strand transfer inhibitor (INSTI) and INSTIs are the latest class of potent anti-HIV drugs. Compared to the first generation INSTIs, raltegravir (RAL) and elvitegravir (EVG), DTG shows a limited cross-resistance profile. More interestingly, clinical resistance mutations to DTG in treatment-naive patents have not been observed to this date. This review summarizes recent studies on resistance mutations to DTG and on our understanding of the mechanisms of resistance to DTG as well as future directions for research.

Effects of Raltegravir or Elvitegravir Resistance Signature Mutations on the Barrier to Dolutegravir Resistance In Vitro

Abstract: The recently approved HIV-1 integrase strand transfer inhibitor (INSTI) dolutegravir (DTG) (S/GSK1349572) has overall advantageous activity when tested in vitro against HIV-1 with raltegravir (RAL) and elvitegravir (EVG) resistance signature mutations. We conducted an in vitro resistance selection study using wild-type HIV-1 and mutants with the E92Q, Y143C, Y143R, Q148H, Q148K, Q148R, and N155H substitutions to assess the DTG in vitro barrier to resistance. No viral replication was observed at concentrations of ≥ 32 nM DTG, whereas viral replication was observed at 160 nM RAL or EVG in the mutants. In the Q148H, Q148K, or Q148R mutants, G140S/Q148H, E138K/Q148K, E138K/Q148R, and G140S/Q148R secondary mutations were identified with each INSTI and showed high resistance to RAL or EVG but limited resistance to DTG. E138K and G140S, as secondary substitutions to Q148H, Q148K, or Q148R, were associated with partial recovery in viral infectivity and/or INSTI resistance. In the E92Q, Y143C, Y143R, and N155H mutants, no secondary substitutions were associated with DTG. These in vitro results suggest that DTG has a high barrier to the development of resistance in the presence of RAL or EVG signature mutations other than Q148. One explanation for this high barrier to resistance is that no additional secondary substitution of E92Q, Y143C, Y143R, or N155H simultaneously increased the fold change in 50% effective concentration (EC50) to DTG and infectivity. Although increased DTG resistance via the Q148 pathway and secondary substitutions occurs at low concentrations, a higher starting concentration may reduce or eliminate the development of DTG resistance in this pathway in vitro.

Greater change in bone turnover markers for efavirenz/emtricitabine/tenofovir disoproxil fumarate versus dolutegravir + abacavir/lamivudine in antiretroviral therapy-naive adults over 144 weeks.

Abstract: Understanding long-term consequences of exposure to individual antiretroviral therapy (ART) components is important in making an initial HIV treatment selection. Initiation of ART is associated with a decrease in bone mineral density (BMD). This initial bone loss is greater with some antiretrovirals, in particular, protease inhibitors [1–4] and tenofovir disoproxil fumarate (TDF) [1,5–9]. The impact on bone health of the integrase strand transfer inhibitor (INSTI) class has not been well characterized. Few studies to date have evaluated the effects of INSTI-containing regimens [either raltegravir (RAL) or elvitegravir] on bone composition over 48 weeks or longer. BMD outcomes tended to be more favorable when RAL was administered as part of a protease inhibitor-sparing or TDF-sparing regimen [6,10–12]; elvitegravir was administered as part of a TDF-containing fixed-dose combination and showed similar decreases in BMD as a TDF-containing, protease inhibitor-based comparator regimen [13]. Dolutegravir (DTG) is the most recently approved INSTI, and no studies to date have evaluated long-term changes in BMD in individuals initiating a DTG-based regimen. Measuring BMD in large, randomized trials is complex, as many sites do not have access to appropriate radiological facilities. As a consequence, most studies of BMD are done by monitoring changes after initiation of ART in a subset of the larger study, limiting the generalizability of conclusions and the participation to individuals seen in tertiary medical centers in the developed world. Bone remodeling occurs throughout life. Changes in biochemical markers of bone remodeling [e.g. both resorption markers: type 1 collagen cross-linked C-telopeptide (CTx) and urinary N-telopeptide; and formation markers: serum bone-specific alkaline phosphatase (BSAP), osteocalcin, and procollagen type 1 N-terminal propeptide (P1NP)] can be used to predict the risk of fracture independently from bone density and the rapidity of bone loss in patients with untreated osteoporosis [14]. In the ASSERT study (NCT00549198), which compared abacavir/lamivudine (ABC/3TC) with TDF/emtricitabine (FTC) administered with efavirenz (EFV), results showed a significantly greater decline in BMD and a significant increase in bone turnover markers (BTMs) in the TDF/FTC arm over 96 weeks [8]. Changes in bone markers have been associated with changes in BMD in HIV-positive individuals: in the RADAR study (NCT00677300) and SMART Body Composition substudy (NCT00027352), early increases in CTx, osteocalcin, BSAP, or P1NP predicted decreases in BMD at 48 weeks [6,15]. The objective of this analysis is to evaluate the changes in BTMs in the SINGLE study (ING114467) through 144 weeks of treatment with either DTG + ABC/3TC or EFV/FTC/TDF.

Pharmacokinetic profile of raltegravir, elvitegravir and dolutegravir in plasma and mucosal secretions in rhesus macaques

Abstract: OBJECTIVES Pharmacokinetic studies in animal models are important for assessing the prophylactic potential of antiretroviral drugs for HIV prevention. This study sought to identify clinically relevant doses of the marketed integrase inhibitors raltegravir, elvitegravir and dolutegravir in macaques and investigate drug penetration and antiviral activity in mucosal secretions. METHODS Macaques received one oral dose of raltegravir, elvitegravir or dolutegravir alone or in combination with emtricitabine and tenofovir disoproxil fumarate followed by drug level measurements in blood and rectal and vaginal secretions. Antiviral activity was investigated in TZM-bl cells exposed to SHIV162p3 in the presence of rectal secretions collected from treated animals. RESULTS Plasma drug concentrations with 50 mg/kg raltegravir or elvitegravir were within the range seen in humans receiving 400-800 mg of raltegravir or 800 mg of unboosted elvitegravir but lower than with 150 mg of elvitegravir boosted with cobicistat. AUC0-24 values for dolutegravir increased proportionally with the dose, with a calculated human-equivalent dose of 20 mg/kg. Elvitegravir showed the highest penetration in rectal and vaginal fluids despite the absence of pharmacological boosting, followed by raltegravir and dolutegravir. Rectal secretions collected at 24 h from treated macaques blocked infection of TZM-bl cells by 50% at dilutions of 1/1000 (raltegravir), 1/800 (dolutegravir) and >1/30 000 (elvitegravir). CONCLUSIONS We defined macaque doses of HIV integrase inhibitors that recapitulate human clinical doses, which will facilitate efficacy and dose escalation studies in macaques. High and sustained drug concentrations and activity in mucosal secretions suggest that integrase inhibitors are promising candidates for HIV prevention.