Showing papers on "Dolutegravir published in 2011"

In Vitro Antiretroviral Properties of S/GSK1349572, a Next-Generation HIV Integrase Inhibitor

Abstract: S/GSK1349572 is a next-generation HIV integrase (IN) inhibitor designed to deliver potent antiviral activity with a low-milligram once-daily dose requiring no pharmacokinetic (PK) booster. In addition, S/GSK1349572 demonstrates activity against clinically relevant IN mutant viruses and has potential for a high genetic barrier to resistance. S/GSK1349572 is a two-metal-binding HIV integrase strand transfer inhibitor whose mechanism of action was established through in vitro integrase enzyme assays, resistance passage experiments, activity against viral strains resistant to other classes of anti-HIV agents, and mechanistic cellular assays. In a variety of cellular antiviral assays, S/GSK1349572 inhibited HIV replication with low-nanomolar or subnanomolar potency and with a selectivity index of 9,400. The protein-adjusted half-maximal effective concentration (PA-EC(50)) extrapolated to 100% human serum was 38 nM. When virus was passaged in the presence of S/GSK1349572, highly resistant mutants were not selected, but mutations that effected a low fold change (FC) in the EC(50) (up to 4.1 fold) were identified in the vicinity of the integrase active site. S/GSK1349572 demonstrated activity against site-directed molecular clones containing the raltegravir-resistant signature mutations Y143R, Q148K, N155H, and G140S/Q148H (FCs, 1.4, 1.1, 1.2, and 2.6, respectively), while these mutants led to a high FC in the EC(50) of raltegravir (11- to >130-fold). Either additive or synergistic effects were observed when S/GSK1349572 was tested in combination with representative approved antiretroviral agents; no antagonistic effects were seen. These findings demonstrate that S/GSK1349572 would be classified as a next-generation drug in the integrase inhibitor class, with a resistance profile markedly different from that of first-generation integrase inhibitors.

Structural and Functional Analyses of the Second-Generation Integrase Strand Transfer Inhibitor Dolutegravir (S/GSK1349572).

Abstract: Raltegravir (RAL) and related HIV-1 integrase (IN) strand transfer inhibitors (INSTIs) efficiently block viral replication in vitro and suppress viremia in patients. These small molecules bind to the IN active site, causing it to disengage from the deoxyadenosine at the 3′ end of viral DNA. The emergence of viral strains that are highly resistant to RAL underscores the pressing need to develop INSTIs with improved resistance profiles. Herein, we show that the candidate second-generation drug dolutegravir (DTG, S/GSK1349572) effectively inhibits a panel of HIV-1 IN variants resistant to first-generation INSTIs. To elucidate the structural basis for the increased potency of DTG against RAL-resistant INs, we determined crystal structures of wild-type and mutant prototype foamy virus intasomes bound to this compound. The overall IN binding mode of DTG is strikingly similar to that of the tricyclic hydroxypyrrole MK-2048. Both second-generation INSTIs occupy almost the same physical space within the IN active site and make contacts with the β4–α2 loop of the catalytic core domain. The extended linker region connecting the metal chelating core and the halobenzyl group of DTG allows it to enter farther into the pocket vacated by the displaced viral DNA base and to make more intimate contacts with viral DNA, compared with those made by RAL and other INSTIs. In addition, our structures suggest that DTG has the ability to subtly readjust its position and conformation in response to structural changes in the active sites of RAL-resistant INs.

Dolutegravir (S/GSK1349572) Exhibits Significantly Slower Dissociation than Raltegravir and Elvitegravir from Wild-Type and Integrase Inhibitor-Resistant HIV-1 Integrase-DNA Complexes

Abstract: The integrase inhibitor (INI) dolutegravir (DTG; S/GSK1349572) has significant activity against HIV-1 isolates with raltegravir (RAL)- and elvitegravir (ELV)-associated resistance mutations. As an initial step in characterizing the different resistance profiles of DTG, RAL, and ELV, we determined the dissociation rates of these INIs with integrase (IN)-DNA complexes containing a broad panel of IN proteins, including IN substitutions corresponding to signature RAL and ELV resistance mutations. DTG dissociates slowly from a wild-type IN-DNA complex at 37°C with an off-rate of 2.7 × 10(-6) s(-1) and a dissociative half-life (t(1/2)) of 71 h, significantly longer than the half-lives for RAL (8.8 h) and ELV (2.7 h). Prolonged binding (t(1/2), at least 5 h) was observed for DTG with IN-DNA complexes containing E92, Y143, Q148, and N155 substitutions. The addition of a second substitution to either Q148 or N155 typically resulted in an increase in the off-rate compared to that with the single substitution. For all of the IN substitutions tested, the off-rate of DTG from IN-DNA complexes was significantly slower (from 5 to 40 times slower) than the off-rate of RAL or ELV. These data are consistent with the potential for DTG to have a higher genetic barrier to resistance, provide evidence that the INI off-rate may be an important component of the mechanism of INI resistance, and suggest that the slow dissociation of DTG may contribute to its distinctive resistance profile.

Antiviral activity, safety, and pharmacokinetics/pharmacodynamics of dolutegravir as 10-day monotherapy in HIV-1-infected adults.

Abstract: Objective: To evaluate the antiviral activity, safety, pharmacokinetics, and pharmacokinetics/pharmacodynamics of dolutegravir (DTG), a next-generation HIV integrase inhibitor (INI), as short-term monotherapy. Design: A phase IIa, randomized, double-blind, dose-ranging study. Methods: In this study, INI-naive, HIV-1-infected adults currently off antiretroviral therapy were randomized to receive DTG (2, 10, or 50mg) or placebo once daily for 10 days in an eight active and two placebo randomization scheme per DTG dose. Placebo patients were pooled for the purpose of analysis. Results: Thirty-five patients (n ¼9 for DTG 2 and 10mg, n ¼10 for DTG 50mg, and n ¼7 for placebo) were enrolled. Baseline characteristics were similar across dosegroups.SignificantreductionsinplasmaHIV-1RNAfrombaselinetoday11were observed for all DTG dose groups compared with placebo (P <0.001), with a mean decrease of 1.51‐2.46log10copies/ml. In addition, a well characterized dose‐response relationship was observed for viral load decrease. Most patients (seven of 10, 70%) receiving DTG 50mg achieved plasma HIV-1 RNA less than 50copies/ml. The pharmacokinetic variability was low (coefficient of variation, range 25‐50%). Plasma HIV-1 RNA reduction was best predicted by Ct using an Emax model. The most common adverse events were diarrhea, fatigue, and headache; the majority of ad verse events were mild or moderate in severity. Conclusion: Dolutegravir demonstrated potent antiviral activity, good short-term tolerability, low pharmacokinetic variability, and a predictable pharmacokinetics/ pharmacodynamics relationship, which support once-daily dosing without a pharmacokinetic booster in integrase-naive patients in future studies. 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins AIDS 2011, 25:1737‐1745

Cross-resistance profile of the novel integrase inhibitor dolutegravir (S/GSK1349572) using clonal viral variants selected in patients failing raltegravir

Abstract: Novel integrase inhibitors are in advanced clinical development, and cross-resistance data are needed to consider the possibility to plan a sequential usage within this class of antiretroviral drugs. Ex vivo phenotypic assays were conducted on 11 wild-type and 27 fully replicating recombinant viruses obtained from 11 patients failing previous raltegravir-containing regimens. Dolutegravir maintained its activity in vitro on viruses with mutations in position 143 and 155. However, viruses with mutation Q148R associated with secondary mutations and the combination Q148H+G140S were instead associated with a reduced level of susceptibility to dolutegravir in vitro.

The HIV-1 integrase G118R mutation confers raltegravir resistance to the CRF02_AG HIV-1 subtype

Abstract: Background: Most of the previous studies that explored the molecular basis of raltegravir resistance were conducted studying the HIV-1 B subtype. It has been shown that the CRF02_AG subtype in relation to its natural integrase (IN) sequence could develop different genetic pathways associated with raltegravir resistance. The aim of this study was to explore resistance pathways preferably used by CRF02_AG viruses compared with subtype B. Methods: Twenty-five HIV-1 CRF02_AG-infected patients failing a raltegravir-containing regimen were studied. IN gene sequences were examined for the presence of previously described IN inhibitor (raltegravir, elvitegravir, dolutegravir and MK-2048) resistance mutations at 20 amino acid positions. Results: Among the 25 studied patients, 7 showed viruses harbouring major raltegravir resistance mutations mainly associated with the 155 genetic pathways and 18 showed viruses harbouring none of them; however, for 1 patient, we found a 118R mutation, associated with MK-2048 in vitro resistance, in a 74M background. For this patient, the phenotypic analysis showed that addition of only the G118R mutation conferred a high level of resistance to raltegravir (fold change ¼ 25.5) and elvitegravir (fold change ¼ 9.2). Conclusions: This study confirmed that mutation pathways for raltegravir resistance could be different between the two subtypes CRF02_AG and B with a preferential use of the 155 mutation in non-B subtypes. A new genetic pathway associated with raltegravir resistance, including the 118R mutation, has also been identified. This new genetic pathway, never described in subtype B, should be further evaluated for phenotypic susceptibility to dolutegravir and MK-2048.

Structural and Functional Analyses of the Second-Generation Integrase Strand Transfer Inhibitor Dolutegravir

Abstract: Raltegravir (RAL) and related HIV-1 integrase (IN) strand transfer inhibitors (INSTIs) efficiently block viral replication in vitro and suppress viremia in patients. These small molecules bind to the IN active site, causing it to disengage from the deoxyadenosine at the 3 end of viral DNA. The emergence of viral strains that are highly resistant to RAL underscores the pressing need to develop INSTIs with improved resistance profiles. Herein, we show that the candidate second-generation drug dolutegravir (DTG, S/GSK1349572) effectively inhibits a panel of HIV-1 IN variants resistant to first-generation INSTIs. To elucidate the structural basis for the increased potency of DTG against RAL-resistant INs, we determined crystal structures of wild-type and mutant prototype foamy virus intasomes bound to this compound. The overall IN binding mode of DTG is strikingly similar to that of the tricyclic hydroxypyrrole MK2048. Both second-generation INSTIs occupy almost the same physical space within the IN active site and make contacts with the 4–2 loop of the catalytic core domain. The extended linker region connecting the metal chelating core and the halobenzyl group of DTG allows it to enter farther into the pocket vacated by the displaced viral DNA base and to make more intimate contacts with viral DNA, compared with those made by RAL and other INSTIs. In addition, our structures suggest that DTG has the ability to subtly readjust its position and conformation in response to structural changes in the active sites of RAL-resistant INs.

Implications of integrase inhibitors for HIV-infected transplantation recipients: raltegravir and dolutegravir (S/GSK 1349572).

Abstract: Summary In the modern era of highly active antiretroviral therapy (HAART), reluctance to perform transplantation (Tx) in HIV-infected individuals is no longer justified. Nonnucleoside reverse transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs), the current first line regimens of HAART, are metabolized by the cytochrome P450 family (CYP3A4). Most NNRTIs induce CYP3A4, whereas PIs inhibit it. Calcinuerin inhibitors (CNIs), which are mandatory for Tx, need the same enzyme complex for their clearance. Therefore, a significant drug-drug interaction (DDI) is encountered between current HAART and CNIs. This results in extreme difficulty in adjusting the optimal dose of CNIs, for which the therapeutic range is narrow. Of interest, integrase inhibitors (INIs) – novel, potent anti-HIV drugs – are mainly metabolized by uridine diphosphate glucuronosyltransferase (UGT) 1A1 and do not induce or inhibit CYP3A4. DDI is presumably absent when NNTRIs or PIs are replaced by INIs. Raltegravir (RAL), a first generation INI, has been introduced into kidney and liver Tx. There is increasing evidence that rejection is well controlled without renal impairment due to CNI over-exposure while persistent, robust suppression of HIV is achieved. Global phase III clinical trials of dolutegravir (DTG), a second generation INI, are currently in progress. In vitro data has suggested that DTG may be less prone to resistance than RAL (referred to as having a higher genetic barrier). The time has come to extensively discuss the implications of INIs in Tx for HIV positive patients.

Therapeutic combination comprising dolutegravir, abacavir and lamivudine

Abstract: A combination comprising a compound of formula (I): ** Formula ** or a pharmaceutically acceptable salt thereof, abacavir or a pharmaceutically acceptable salt thereof and lamivudine.

3-Hydroxy-6,7-dihydropyrimido[2,1-c][1,4]oxazin-4(9H)-ones as new HIV-1 integrase inhibitors WO2011046873 A1

Abstract: Since the discovery of raltegravir, the first FDA-approved integrase inhibitor, Merck and other pharmaceutical companies have continued their research programs in order to introduce novel molecules as second generation integrase inhibitors. Elvitegravir (Japan Tobacco/Gilead) and dolutegravir (Shionogi/GlaxoSmithKline) are in advanced stages of clinical development. Bristol-Myers Squibb has developed molecules leading to BMS-707035, which was stopped at the Phase II clinical trial stage. Herein is presented the last patent from this company where, in particular, new 3-hydroxy-6,7-dihydropyrimido[2,1-c][1,4]oxazin-4(9H)-ones are synthesized and their biological properties given.

Dolutegravir Dosage Considerations for Patients Taking Etravirine

Abstract: The combination of dolutegravir (a promising once-daily unboosted integrase inhibitor) and etravirine (a second-generation nonnucleoside reverse transcriptase inhibitor) is a potentially attractive option for patients infected with multidrug-resistant HIV. However, possible interactions between the two drugs, which share similar metabolic pathways, are still being evaluated. Two open-label crossover …