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Purpose of Review: Symptomatic cerebrospinal fluid (CSF) HIV escape defines the presence of neurological disease in combination antiretroviral therapy (cART)-treated persons due to HIV replication in CSF despite systemic suppression or to higher viral replication in CSF than in plasma. The aim was to search for cases of recurrent symptomatic CSF escape and to define their characteristics., Recent Findings: By review of the literature, we identified symptomatic CSF escape relapses in three patients who had shown clinical remission of a first escape episode following cART optimization. By examination of our cohort of 21 patients with symptomatic CSF escape, we identified five additional patients. In the latter, viral escape relapsed over a median follow-up of 108 months because of low adherence or upon treatment simplification of a previously optimized regimen. cART reoptimization based on resistance profile and potential drug neuropenetration and efficacy led to relapse resolution with no further episodes after a median follow-up of 50 months from relapse. The observation that CSF escape may relapse highlights the importance of long-term neuro-suppressive regimens after a first episode and supports the role of the brain as a reservoir for HIV.

This study assessed the 48-week efficacy of an antiretroviral therapy including maraviroc following the assessment of co-receptor tropism by use of Geno2Pheno algorithm or the Trofile phenotypic assay in failing treatment-experienced HIV-1 patients. This was a multicenter, randomized, open-label, non-inferiority trial. Treatment-experienced subjects with HIV-RNA ≥500 copies/mL were randomized (1:1) to undergo co-receptor tropism testing by the Geno- 2Pheno algorithm (with a false positive rate >10%) or the Trofile assay before starting a new antiretroviral treatment which included maraviroc. The primary endpoint was the 48 week proportion of patients with treatment success (TS). Intention-to-treat analyses are also reported. One hundred and fifty-five experienced patients were analysed: 77 patients in the Trofile arm and 78 in the Genotype arm. The 48-week proportion of TS was 87% in the Trofile arm and 89% in the Genotype arm (difference: 1.5%, 95%CI: -8.9% to 11.8%) suggesting non-inferiority. In the Trofile arm, 10 patients had treatment failure: 5 viral rebound, 5 discontinuations. In the Genotype arm, 9 patients had treatment failure: 7 viral rebound, 2 lost to follow-up. CD4+ significantly increased from baseline to week 48 in both arms. 48-week treatment success was similar for maraviroc-including therapy prescribed following the Trofile phenotypic assay or Geno2Pheno algorithm.

Maraviroc (MVC) is licensed in clinical practice for patients with R5 virus and virological failure; however, in anecdotal reports, dual/mixed viruses were also inhibited. We retrospectively evaluated the evolution of HIV-1 coreceptor tropism in plasma and peripheral blood mononuclear cells (PBMCs) of an infected adolescent with a CCR5/CXCR4 Trofile profile who experienced an important but temporary immunological and virological response during a 16-month period of MVC-based therapy. Coreceptor usage of biological viral clones isolated from PBMCs was investigated in U87.CD4 cells expressing wild-type or chimeric CCR5 and CXCR4. Plasma and PBMC-derived viral clones were sequenced to predict coreceptor tropism using the geno2pheno algorithm from the V3 envelope sequence and pol gene-resistant mutations. From start to 8.5 months of MVC treatment only R5X4 viral clones were observed, whereas at 16 months the phenotype enlarged to also include R5 and X4 clones. Chimeric receptor usage suggested the preferential usage of the CXCR4 coreceptor by the R5X4 biological clones. According to phenotypic data, R5 viruses were susceptible, whereas R5X4 and X4 viruses were resistant to RANTES and MVC in vitro. Clones at 16 months, but not at baseline, showed an amino acidic resistance pattern in protease and reverse transcription genes, which, however, did not drive their tropisms. The geno2pheno algorithm predicted at baseline R5 viruses in plasma, and from 5.5 months throughout follow-up only CXCR4-using viruses. An extended methodological approach is needed to unravel the complexity of the phenotype and variation of viruses resident in the different compartments of an infected individual. The accurate evaluation of the proportion of residual R5 viruses may guide therapeutic intervention in highly experienced patients with limited therapeutic options.

Objective: The aim of the present study was to evaluate the virological response to a new antiretroviral treatment (ART2) after failure of a nonnucleoside reverse transcriptase inhibitor (NNRTI) plus two nucleoside reverse transcriptase inhibitors (NRTIs)-containing regimen., Design: Retrospective observational study based on the Italian ARCA cohort database. Adult patients were included if they had a virological failure (defined as plasma viral load above 500 copies/ml in two subsequent visits) while on a treatment with one NNRTI plus 2 NRTIs, had an available HIV genotype., Results: Patients on ART2 were followed up for 791 person/year and median follow up was 10.8 months(IQR 5.2-26). Variables associated with reduced risk of ART2 virological failure at univariable analysis had started the treatment in recent years (HR 0.90; 95% CI 0.86-0.94, p < 0.0001) and duration of previous NNRTI treatment (HR 0.995; 95%CI 0.990-0.990, p=0.045). Variables associated with increased risk of virological failure of ART2 were a higher plasma viral load (pVL) at baseline(HR 1.2; 95% CI 1.07-1.34, p=0.002) and the type of treatment, in particular an unboosted PI-containing regimen vs. a boosted PI-containing regimen(HR 1.6; 95%CI 1.25-2.04 p < 0.0001) and a non-PI-containing vs. a boosted PI-containing regimen (HR 1.56; 95% CI 1.25-1.96, p < 0.0001). At multivariable analysis, year of ART2 start, pVL at NNRTI failure as well as using a boosted PI remained statistically significant predictors., Conclusion: This study highlights the role of drugs with high genetic barrier, such as boosted PI as a cornerstone to build a new antiretroviral treatment in patients failing a NNRTI based regimen.

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 objective of this study was to address the evolution of human immunodeficiency virus type 1 (HIV-1) mutations resistant to the integrase inhibitor raltegravir after drug interruption. Thirteen HIV-1 infected patients undergoing virological failure due to the selection of raltegravir-resistant variants, who had interrupted raltegravir treatment, were enrolled. For all patients, the virological failure was associated with the selection of variants, with mutations conferring resistance to all of the drugs present in their regimens. Patients were prospectively monitored at baseline (raltegravir interruption) and every 4-24 weeks for clinical, virological and immunological parameters, including HIV-1 viraemia, CD4(+) T-cell counts, and sequence analysis of the HIV-1 integrase sequence. Reversion to the wild-type HIV-1 integrase sequence genotype was observed between 4 and 36 weeks after raltegravir withdrawal in eight out of the 13 patients. Reversion was not observed in three patients. In two patients, reversion was partial at week 24 from raltegravir interruption. These results highlight that in eight out of 13 patients under treatment with raltegravir and experiencing a virological failure, HIV-1 variants harbouring mutations associated with raltegravir resistance become undetectable after drug interruption within a few weeks (in some cases, very rapidly). This occurs under different therapy regimens and in patients receiving 3TC mono-therapy. In the other patients, complete reversion of the integrase sequence is not observed, and either primary or secondary resistance mutations are fixed in the replication competent viral population in vivo also for long time, suggesting that other factors may influence this dynamic process., (2010 The Authors. Clinical Microbiology and Infection; 2010 European Society of Clinical Microbiology and Infectious Diseases.)

Objectives: To understand the dynamic viral evolution observed during failure on raltegravir-containing regimens, we studied the genotypic and phenotypic patterns of resistance to raltegravir and the residual replication capacity (rRC) of HIV-1 variants selected in vivo., Methods: Clonal genotypic analyses were performed on sequential HIV-1 integrase sequences amplified from 11 failing patients and sampled every 4-24 weeks for up to 64 weeks. Fully replicating recombinant viruses were generated using modified vectors in which selected viral integrase genes amplified from patients' plasma were cloned. rRC was measured by a novel multiple cycle competition assay. Resistance to raltegravir and the rRC of resistant HIV-1 variants selected in vivo were evaluated in purified CD4+ T cells., Results: In all of the patients but one, failure was associated with selection of mutations in positions 143, 148 or 155. Unlike mutations at position 143 (Y143S/K/R), identified alone or in combination with others, mutations at position 148 and 155 were always found in combination. A wide range of resistance levels to raltegravir [from 10- to 770-fold change in 50% inhibitory concentration (IC(50)) compared with baseline] was observed using recombinant viral clones. Finally, rRC was not significantly altered in highly resistant variants., Discussion: Two patterns of viral evolution were observed in the resistant viral populations, driving the variants towards a fast (most of them with G140S + Q148H mutations) or progressive increase in resistance to raltegravir. These results may have implications either for the evaluation of genotypic results, or for the correct clinical use of the compound.

Objectives: To test retrospectively the ability of four freely available rules-based expert systems to predict short- and medium-term virological outcome following an antiretroviral treatment switch in pre-treated HIV-1 patients., Methods: The HIV-1 genotype interpretation systems (GISs) HIVdb, ANRS, Rega and AntiRetroScan were tested for their accuracy in predicting response to highly active antiretroviral therapy using 8 week (n = 765) and 24 week (n = 634) follow-up standardized treatment change episodes extracted from the Italian Antiretroviral Resistance Cohort Analysis (ARCA) database. A genotypic sensitivity score (GSS) was derived for each genotype-treatment pair for the different GISs and tested as a predictor of virological treatment outcome by univariable and multivariable logistic regression as well as by receiver operating characteristic curve analysis. The two systems implementing drug potency weights (AntiRetroScan and Rega) were evaluated with and without this correction factor., Results: All four GSSs were strong predictors of virological treatment outcome at both 8 and 24 weeks after adjusting for baseline viro-immunological parameters and previous drug exposure (odds ratios ranging from 2.04 to 2.43 per 1 unit GSS increase; P < 0.001 for all the systems). The accuracy of AntiRetroScan and Rega was significantly increased by drug potency weighting with respect to the unweighted versions (P

Background: This study aimed to examine the evolution of genotypic drug resistance prevalence in treatment-failing patients in the multicentre, Italian, Antiretroviral Resistance Cohort Analysis (ARCA)., Methods: Patients with a drug resistance genotype test performed between 1999 and 2006 at failure of a combination antiretroviral therapy and with complete treatment history were selected. The prevalence of resistance was measured overall, per calendar year, per drug class and per treatment line at failure., Results: The overall resistance prevalence was 81%. Resistance to nucleoside reverse transcriptase inhibitors (NRTIs) declined after 2002 (68% in 2006; chi(2) for trend P=0.004); resistance to non-NRTIs (NNRTIs) stabilized after 2004; and resistance to protease inhibitors (PIs) declined after 2001 (43% in 2006; P=0.004). In first-line failures, NRTI resistance decreased after 2002 (P=0.006), NNRTI resistance decreased after 2003 (P=0.001) and PI resistance decreased after 2001 (P<0.001). Independent predictors of resistance to any class were HIV type-1 transmission by heterosexual contacts as compared with injecting drug use, a higher number of experienced regimens, prior history of suboptimal therapy, higher viral load and CD4+ T-cell counts, more recent calendar year and viral subtype B carriage, whereas the use of PI-based versus NNRTI-based regimens at failure was associated with a reduced risk of resistance. There was an increase of type-1 thymidine analogue and of protease mutations L33F, I47A/V, I50V and I54L/M, whereas L90M decreased over calendar years., Conclusions: During more recent years, emerging drug resistance has decreased, particularly in first-line failures. The prevalence continues to be high in multiregimen-failing patients.

Background: There is still considerable uncertainty as to the best algorithm for interpreting human immunodeficiency virus (HIV) genotyping results., Methods: A total of 318 subjects with HIV RNA levels of >1000 copies/mL were enrolled in 41 centers throughout Italy from 2001 through 2003, stratified on the basis of their drug history, randomized (1:1) to 2 arms to have their treatments modified on the basis of the results of HIV genotyping (as interpreted by virtual phenotype analysis or with use of a rule-based interpretation system), and followed up for 48 weeks. At least 1 nucleoside reverse-transcriptase inhibitor and 1 protease inhibitor had to be included in any new regimen; nonnucleoside reverse-transcriptase inhibitor-naive patients were also prescribed a nonnucleoside reverse-transcriptase inhibitor. Only drugs licensed in Italy were allowed. The primary end point was a decrease in HIV RNA level to <400 copies/mL by week 12 according to on-treatment analysis., Results: The mean (+/- standard deviation) values at baseline were as follows: HIV RNA level, 4.1+/-0.74 log(10) copies/mL; CD4(+) T lymphocyte count, 410+/-262 cells/microL; reverse-transcriptase mutations, 4.8+/-2.9; and protease mutations, 2.8+/-2.5. There were 133 patients (41.8%) who were nonnucleoside reverse-transcriptase inhibitor naive and protease inhibitor experienced, 63 patients (19.8%) who were nonnucleoside reverse-transcriptase inhibitor experienced and protease inhibitor naive, and 122 patients (38.4%) who were 3-class experienced. A total of 192 patients completed 12 weeks of the treatment regimen assigned at baseline; at 12 weeks, 66.3% of patients in the virtual phenotype arm and 71.3% of patients in the rule-based interpretation arm had HIV RNA levels of <400 copies/mL (P = .46). No statistically significant difference between arms was observed by intention-to-treat analysis., Conclusion: Both the virtual phenotype and rule-based interpretation methods of HIV genotyping can guide the selection of effective antiretroviral drugs for a salvage regimen.

Objective: We compared the immunological and clinical outcomes of lamivudine monotherapy and complete therapy interruption in the treatment of HIV-1-infected patients harbouring lamivudine-resistant virus., Methods: This 48-week, open-label pilot study randomly assigned HIV-infected patients receiving lamivudine-containing HAART and harbouring the M184V mutation to monotherapy with lamivudine 300 mg once daily (lamivudine group) or the discontinuation of all antiretroviral drugs (TI group). The primary endpoint was the occurrence of immunological or clinical failure; immunological failure was defined as the first report of a CD4 T-cell count less than 350 cells/microl, and clinical failure as the occurrence of a Centers for Disease Control and Prevention grade B or C event. The data were analysed on the basis of the intention-to-treat principle., Results: By week 48, 20 of 29 patients in the TI group (69%; 95% CI 51-83%) and 12 of 29 in the lamivudine group (41%; 95% CI 26-59%) had discontinued the study because of immunological or clinical failure, which was significantly delayed in the lamivudine group (P = 0.018). Only patients in the TI group (6/29, 20.7%) experienced grade 3-4 clinical adverse events at least possibly related to HIV-1 (P = 0.02). The mean decline in CD4 cell percentage, viral rebound and recovery of HIV-1 replication capacity were significantly lower in the lamivudine group. The 24-week virological and immunological response after therapy resumption in patients who prematurely discontinued the study was similar in the two groups., Conclusion: In HIV-1-infected patients harbouring a lamivudine-resistant virus, lamivudine monotherapy may lead to a better immunological and clinical outcome than complete therapy interruption.

Patients infected with HIV-1 with more than 1000 HIV-1 RNA copies/mL, who were genotyped within 3 months before starting stavudine and treated for at least 3 months with a stable stavudine-containing highly active antiretroviral therapy, were selected from our database to identify the determinants of response to stavudine. Nonresponse was defined as a failure to achieve HIV-1 RNA level of less than 400 copies/mL or a reduction of more than 2 log10 by week 12. Univariate logistic analysis was used to elicit the failure-associated reverse transcriptase mutations (scored 1 to develop a genotype score). Eighty-one patients were eligible for the analysis, including 75 (93%) who previously received zidovudine. Thirty-five (43%) were nonresponders. Univariate logistic analysis revealed the following failure-associated mutations: 41L (P = 0.0001), 44D (P = 0.02), 118I (P = 0.0006), 184V (P = 0.04), 210W (P = 0.0004), and 215Y (P = 0.002) for a median stavudine score of 2. Failure was observed in 7 (18.9%) of 37 patients with a score less than 2, compared with 28 (63.6%) of 44 patients with a score of 2 or greater (P < 0.0001). The multivariable analysis showed that the 118I mutation (P = 0.04) was the only independent genotypic predictor of failing on a stavudine- containing highly active antiretroviral therapy.

To investigate the dynamics of the K103N mutation following the withdrawal of non-nucleoside reverse transcriptase inhibitors (NNRTIs), we selected the Human Immunodeficiency Virus (HIV)-infected patients with the mutation at the time or after the failure of an NNRTI-containing regimen from an observational database. Of 62 patients fulfilling the inclusion criteria, 39 continued antiretroviral treatment without NNRTIs (group A), whereas 23 discontinued all antiretrovirals after NNRTI failure (group B). A total of 149 tests were analysed, with a median (IQR) of two (2-3) tests/patient. The overgrowth of wild-type virus at position 103 was observed in 14 subjects in group A (36%) and nine in group B (39%). No significant trend was found in relation to the disappearance of K103N variants in either group, but patients tested while receiving antiretrovirals had a significantly higher probability of retaining the K103N mutation over 24 months than those tested during treatment interruption (P = 0.007). In conclusion, following NNRTI discontinuation, HIV variants carrying the K103N mutation are not overgrown for long by wild-type quasispecies at this position in the majority of patients, although treatment interruption favours their disappearance. This suggests that the K103N mutation per se has little impact on viral fitness in vivo.

Data from 20 highly drug-experienced HIV-infected patients receiving tenofovir plus didanosine as part of a salvage regimen were analysed. At baseline, all but one patient harboured a virus bearing at least one nucleoside excision mutation (NEM); in 13 cases (65%) three or more NEM were detectable. After a median of 26 weeks of treatment, two patients (10%) selected the 65R mutation. These results support the hypothesis that NEM hinder the selection of this mutation.

Genotypic testing includes several steps (RNA purification, RT-PCR amplification, DNA sequencing, sequence editing and analysis) that should be individually controlled. In our laboratory, we have added to this step-by-step internal control a final phylogenetic quality control: this is performed every time a sequence is obtained from a patient previously subjected to the same test. Each sequence with this characteristic is routinely compared with sequences from previous samples of the same patient by multiple alignment and a neighbor-joining tree by using Kimura two-parameter method is constructed. To validate the quality control procedure, we have aligned and calculated the mean similarity of the reverse transcriptase (first 984 nucleotides) and protease (whole gene) sequences from 30 patients whose virus was completely wild-type for both reverse transcriptase and protease. In the same tree, we have added the sequences obtained from 5 out of the 30 patients, tested at a second time point. The wild type sequences have shown a mean inter-sample divergence of 2.9%, and all the sequence pairs from individual patients clustered together in the tree constructed with the nucleotide sequences, while the tree constructed with the inferred aminoacid sequences did not always permit to cluster the sequences from the same patients. This indicates that: 1) the phylogenetic analysis of nucleic acid sequences can be useful to rule out sample mix-up; 2) the belonging of a sequence to each individual patient can efficiently be assessed also in the cases of extreme divergence in terms of drug resistance mutations.

Chronic hepatitis C virus (HCV) is an independent risk factor for antiretroviral-related hepatotoxicity, but little is known about the frequency of severe liver toxicity in patients with HIV-HCV coinfection first treated for HCV (pretreated). The aim of this prospective study of 105 patients was to compare the incidence of progression to severe antiretroviral-related liver toxicity in 66 patients pretreated (36 with interferon-alpha [IFNalpha], 30 with IFNalpha plus ribavirin), and 39 patients not pretreated. The subjects could choose whether to receive anti-HCV therapy. Severe liver toxicity was defined as alanine aminotransferase (ALT) level > or =5-times the upper limit of normal in patients with normal baseline levels and > or =3.5-times in those with increased baseline levels. The authors also estimated the hepatotoxicity-related risk of discontinuing antiretroviral therapy. During antiretroviral therapy, 10 subjects (9.5%) experienced severe hepatotoxicity: 4 of 66 pretreated patients and 6 of 39 untreated patients (24-month survival: 94% +/- 2.9% vs. 85% +/- 5.8%). After adjusting for baseline CD4 cell counts, ALT levels, histologic scores, HCV and HIV viremia, HCV genotype (genotype 1 in 29% of pretreated patients and 20% of patients not pretreated), and previous anti-HCV therapy, the risk of discontinuing anti-HIV treatment was significantly higher in the anti-HCV untreated patients (RR = 10.4; 95% CI: 1.6-66; p =.0127) and in those with increased baseline ALT levels (RR = 1.014; 95% CI: 1.006-1.021; p =.0005). The authors' data suggest that previous treatment of chronic active HCV is an independent factor associated with a decrease of severe liver toxicity as the result of a subsequent antiretroviral regimen. The authors also confirm that the baseline level of ALT is an important prognostic factor for increased liver damage during antiretroviral therapy.

The prevalence of drug resistance associated with the failure of non-nucleoside reverse transcriptase inhibitor ( NNRTI)-based regimens and the predictors of resistance to Etravirine ( ETR) were assessed in 2854 subjects: 39 < 18 (paediatric) and 2815 ≥ 18 (adult) years old. These subjects failed to respond to their current NNRTI treatment, were three-class experienced and had been exposed to NNRTI for ≥3 months. A total of 1827 adult (64.9%) and 32 paediatric subjects (82.1%) harboured the virus with at least one ETR mutation. V179I, Y181C and G190A were the most frequent mutations in both groups. A significantly increased risk of ETR resistance with all three algorithms (Monogram ( MGR) >3, Tibotec ( TBT) >2 and enhanced MGR ( ENH) ≥4) emerged in the paediatric population. Multivariate analysis revealed an increased risk of developing TBT >2 for NNRTI exposure, ENH ≥4 for NNRTI and EFV exposure in paediatric subjects; NVP exposure and higher (≥3.5 log10) HIV- RNA values for all three algorithms in adult subjects, whereas CD4 ≥ 200/μL appeared to be protective. The risk of being ETR resistant was more than doubled for paediatric vs. adult subjects, probably due to a more extensive use of NNRTI and an incomplete virological control. [ABSTRACT FROM AUTHOR]