Alejandro González-Serna

Correlation between the Trofile® test and virological response to a short-term maraviroc exposure in HIV-infected patients

OBJECTIVES The current validated assay to determine tropism of HIV variants is Trofile, which has some limitations. The aim of this work was to correlate the virological response to a short-term maraviroc exposure with Trofile. METHODS From 1 July 2008 to 1 March 2009, 34 consecutive HIV-infected patients with detectable viral load during the last 6 months began an 8 day exposure to maraviroc (MCT group); six HIV-infected patients without antiretroviral therapy received no treatment (control group). Plasma viral load was evaluated on days 0, 2, 5 and 8. Baseline Trofile was performed in MCT group patients. The maraviroc clinical test (MCT) was considered positive if viral load was undetectable (< 40 HIV-RNA copies/mL) or a reduction > or = 1 log(10) HIV-RNA copies/mL was achieved after 8 days of maraviroc exposure. RESULTS Global concordance between MCT and Trofile was 93.5%. In patients with R5 virus according to Trofile, MCT was positive in 19/20 (concordance 95%); in patients with dual/mixed virus, MCT was negative in 10/11 (concordance 90.9%). An additional phenotypic tropism assay was performed in patients with discordance between MCT and Trofile, being concordant with MCT in both cases. Three patients showed a non-reportable Trofile result, and all of them achieved undetectability after MCT. CONCLUSIONS A clinical approach like short-term maraviroc exposure could be an additional resource to genetic and phenotypic HIV tropism assays. This clinical approach shows high concordance with Trofile, and could allow patients with non-reportable results by Trofile to benefit from maraviroc therapy.

Different biological significance of sCD14 and LPS in HIV-infection: Importance of the immunovirology stage and association with HIV-disease progression markers

OBJECTIVES Bacterial lipopolysaccharide (LPS) and soluble CD14 (sCD14) levels have been indistinctly used to measure bacterial translocation independently of the immunovirological stage in HIV infection; however, when the association of both markers with different HIV-progression end-points has been studied, discrepant results have been reported. The aim of this study was to assess the relationship between LPS and sCD14 in different HIV-infection immune stages and to determine the relationship between these biomarkers with established HIV-disease-progression-related markers, as T-cell immune activation, high-sensitivity C-reactive protein and D-dimer. METHODS Seventy-three chronically HIV-1-infected patients with detectable HIV-1 RNA levels were analyzed. LPS levels by use of limulus lysate assay, sCD14, intestinal fatty acid binding protein and inflammation-coagulation-associated biomarkers were assessed. RESULTS In this study, we found that LPS and sCD14 levels were only associated when low CD4+ T-cell levels and high HIV RNA levels were present. In addition, only sCD14 levels, but not LPS, were independently associated with HIV-disease progression-related markers, supporting the clinical importance of sCD14. CONCLUSIONS These results indicate that LPS and sCD14 have a different biological significance and should not be indistinctly used without taking the HIV immunovirological stage into account.

TROCAI (Tropism Coreceptor Assay Information): a New Phenotypic Tropism Test and Its Correlation with Trofile Enhanced Sensitivity and Genotypic Approaches

ABSTRACT The only clinically validated assay available to determine HIV tropism is Trofile, an assay that possesses some limitations. Our first aim was to develop a new phenotypic tropism test (TROCAI [tropism coreceptor assay information]) and to categorize results generated by this test according to the virological response to a short-term exposure to the CCR5 receptor antagonist maraviroc (maraviroc clinical test). Our second aim was to compare TROCAI results to those obtained by Trofile enhanced sensitivity (ES) and to different genotypic algorithms. TROCAI assayed HIV tropism in 33 HIV-infected patient viral isolates obtained from a modified coculture, followed by multiple infection cycles of indicator cells. TROCAI obtained a reportable result in all patients with viral loads of >500 HIV RNA copies/ml and in 3/6 patients with <500 HIV RNA copies/ml (30/33 patients, 91.9%). Patients who responded to maraviroc had an X4-using virus proportion in indicator cell supernatant of 0 to 0.41%. Hence, we used the threshold of 0.5% to categorize TROCAI results as R5 (<0.5%) or dual/mixed (>0.5%). The concordance between TROCAI and Trofile (ES) was 22/24 (91.6%), and with genotypic approaches it was 22/26 (84.6%). TROCAI results, which were categorized in this study by the maraviroc clinical test, could be used as a test in addition to those currently used to select patients for treatment with CCR5 antagonists.

Temporal trends in the discontinuation of first-line antiretroviral therapy

OBJECTIVES The aim of this study was to describe the rates and predictors of discontinuing first-line antiretroviral therapy in the different eras of treatment over a nearly 20 year period initiated in British Columbia between 1992 and 2010. METHODS All naive adults who started antiretroviral therapy (first-line antiretroviral therapy) at any hospital or clinic in British Columbia (Canada) in 1992-2010 were included in this population-based retrospective cohort study. We were primarily interested in whether the era of treatment (1992-95, 1996-2000, 2001-05 and 2006-10) was associated with discontinuation (stopping or switching of initial treatment) within 3 years of starting therapy. Weibull survival analysis was used to model the era of treatment and its association with time to discontinuation. RESULTS The study included 7901 patients. Overall, the probability of discontinuing at 12, 24 and 36 months of treatment was 52%, 68% and 76%, respectively. In the adjusted model, variables associated with discontinuing were earlier treatment era, younger age, low adherence and lower baseline CD4 count. Regarding the 2006-10 period, the probability of discontinuing at 12, 24 and 36 months was 36%, 47% and 53%, respectively. In the adjusted model, the variables associated with discontinuation were younger age, female gender, AIDS-defining illnesses at baseline, low adherence and a protease inhibitor (PI)-based regimen. CONCLUSIONS Discontinuation rates of first-line therapy have decreased over time, but are still quite high even for the latest drug combinations. In the most recent era, younger women on a PI regimen and those not achieving optimal adherence had the highest risk of discontinuing first-line antiretroviral therapy.

Effect of Maraviroc on HIV Disease Progression-Related Biomarkers

ABSTRACT The potential effect of blocking the CCR5 receptor on HIV disease progression biomarkers is not well understood. We showed that an 8-day maraviroc (MVC) monotherapy clinical test (MCT) can be used in selecting patients to receive MVC-containing combined antiretroviral therapy (cART). Using this MCT model, we assessed the effect of MVC on several HIV disease progression biomarkers during the MCT (MVC-specific effect) and following short-term (12-week) cART. We compared 45 patients on MVC monotherapy with a control group of 25 patients on MVC-sparing cART. We found that MVC did not modify any biomarkers in patients that had no virological response after the MCT. MVC-specific effects in patients with virological responses included increased CD8+ T-cell activation and senescence levels, preservation of an increase in soluble CD14 (sCD14), and a decrease in D dimer levels. After 12 weeks, MVC-containing cART increased CD8+ T-cell counts and preserved CD4+ T-cell senescence levels compared with MVC-sparing cART. Moreover, there was a decrease in sCD14 levels in patients that received MVC-containing cART. In conclusion, effects compatible with CD8+ T-cell redistribution in peripheral blood were observed after MVC therapy. However, MVC was associated with a favorable profile in HIV disease progression biomarkers only in patients with a virological response. These results support a potential clinical benefit of a therapy which includes MVC in HIV-infected patients.

Discordance rates between Trofile test and short-term virological response to maraviroc.

Enhanced sensitivity Trofile (ES-Trofile) is the most frequently used technique to assay HIV tropism. A clinical approach to predict CCR5-antagonists efficacy, based on the virological response to a short-term maraviroc exposure (Maraviroc Clinical Test, MCT), has been recently reported. We compared the results of ES-Trofile with MCT in 47 HIV-infected patients, and a global discordance around 15% was observed between the phenotypic method and the clinical approach. Discordance results were mainly found in patients with an ES-Trofile reported as dual/mixed. These provocative results might have important clinical implications and should be considered in order to accurately prescribe treatment with CCR5 antagonists.

Long-Term Immunovirogical Effect and Tolerability of a Maraviroc- Containing Regimen in Routine Clinical Practice

OBJECTIVES to analyze the long-term immunovirological effect and tolerability of a maraviroc-containing antiretroviral therapy in viraemic and pretreated HIV-infected patients with a high prevalence of hepatitis C virus (HCV) coinfection. METHODS forty-six R5 HIV-infected patients (48% HCV-coinfected) started a maraviroc-containing antiretroviral regimen, including patients with multidrug resistant virus and patients after first virologic failure. A retrospective study was performed, analysing percentage of patients with undetectable viral load, mean CD4+ gain, liver enzymes, clinical events and treatment modification up to week 48. RESULTS Raltegravir plus a boosted protease inhibitor was combined with maraviroc in 65.2% of the patients (mainly patients with multidrug resistant virus), while the coformulation lamivudine/abacavir was combined with maraviroc in 26.1% (all of them patients after first virologic failure). After 48 weeks on maraviroc-containing regimen, 96.3% of the patients had achieved undetectability and a mean CD4+ count increase of 151 cells/mm3 was observed. Liver enzymes did not increase along the follow up. One patient died after 24 weeks follow up due to heroin overdose. One patient developed a non-Hodgkin lymphoma after 36 weeks follow up, despite undetectable viral load and significant CD4+ increase was achieved (the only AIDS-defining event observed). Treatment modification was performed in 19.6% of the patients: 77.7% of them experienced a treatment simplification and only 1/46 suspended maraviroc. CONCLUSIONS maraviroc-containing regimen is long-term effective and well tolerated in HIV-infected patients in routine clinical practice and in different clinical scenarios.

CD8 TCR β chain repertoire expansions and deletions are related with immunologic markers in HIV-1-infected patients during treatment interruption

BACKGROUND HIV-1-infected individuals progressively loss CD4(+) T cells leading to immunosuppression and raising the risk of opportunistic infections. CD8(+) T-cells play an important role in the immune response against virus infections through their TCR. OBJECTIVE To evaluate the CD8-TCR repertoire and immunologic markers in HIV-1-infected patients. STUDY DESIGN Ten chronic HIV-1-infected individuals on prolonged effective antiretroviral treatment (ART) were analyzed at baseline (before treatment interruption), after at least one year of treatment interruption (TI) and after at least one year from ART resume (TR). Twenty-four TCR-Vβ gene families were analyzed by a modified CDR3 spectratyping method in isolated CD8(+) T-cells. Immune activation, exhaustion and subpopulation markers were analyzed by flow cytometry. RESULTS Expansion of Vβ10, Vβ14 and Vβ15 families, associated with low cell activation and stable exhaustion markers, were found at TI. Moreover, an increment of effector memory cells was found. Besides, depletion of Vβ20, Vβ28, and Vβ29 families, associated with an increase in cell activation and exhaustion markers, at TI were also found. These alterations seemed to be more pronounced in patients who had longer time from diagnosis. ART seemed to restore altered CD8(+) T-cell repertoire and most of the immunologic markers. CONCLUSIONS During TI (that was more pronounced in patients with longer HIV-1 infection) it was observed the expansion of Vβ families correlated with decreased cell activation, while Vβ families correlated with cell activation and exhaustion were depleted. These specific repertoire alterations reverted after ART resume.

Patients on a combined antiretroviral therapy after maraviroc clinical test show no immunovirological impairment

The maraviroc clinical test (MCT) is a clinical approach to establish the indication of maraviroc treatment. In this study, we analysed the long-term outcome of patients receiving a combined antiretroviral therapy (cART) selected according to MCT results. Ninety-two consecutive HIV-infected patients underwent MCT. A virological response (<40 HIV-RNA copies/ml after 24 weeks) was observed in 76/92 patients (82.6%). These patients (n=76) were included in a time to treatment failure analysis; after a mean follow-up period of 88 weeks, treatment failure was confirmed in 14 patients (18.4%). Tropism switch during MCT was observed in 3/35 patients (8.6%); these patients experienced excellent long-term outcome on cART. In conclusion, MCT should be considered as an additional method before CCR5-antagonists prescription.

Short-term maraviroc exposure, a clinical approach to decide on maraviroc prescription in HIV-1-infected treatment-naïve patients

Dear editor Woollard and Kanmogne1 have generated an exhaustive review on maraviroc and its use in human immunodeficiency virus (HIV) infection. Within their interesting dissertation, they discuss about the maraviroc clinical test (MCT), a clinical approach developed in our group in order to decide candidate patients to receive maraviroc as part of a further combined antiretroviral therapy, as an alternative to genotypic and phenotypic tropism assays.2 Based on our results, they state that MCT could help to determine/confirm the genotypic/phenotypic HIV-1 tropism, particularly in patients with nonreportable results by Trofile®. Subsequently, they note that “no concordance” between standard V3-based genotypic tropism assays and virological response to maraviroc monotherapy was found, according to previous results generated by our group.3 Finally, based on the results of Hernandez-Novoa et al,4 they conclude that short-term maraviroc exposure cannot predict viral tropism in treatment-naive patients. In our opinion, MCT is an alternative tool to be used in clinical practice to decide CCR5-antagonist prescription in HIV-infected subjects, both in treatment-experienced and -naive patients. Discordances between phenotypic and genotypic methods have been found.5 Moreover, our group developed MCT, a drug sensitivity test but not a tropism assay, and again discordances between MCT and different tropism methods including deep-sequencing were found.5,6 Hence, it has not been established as a “gold standard” to be used in clinical practice before prescribing maraviroc. We consider that the virological response to the drug should be the most important criteria in order to decide maraviroc prescription, and not a categorical tropism result. Therefore, we use MCT not just to confirm a genotypic/phenotypic tropism result and not particularly in patients with a nonreportable result by Trofile® but in all patients. Regarding the naive scenario, our group has explored this issue in a recently published work,7 confirming that MCT is a reliable tool to decide maraviroc prescription in naive HIV-infected subjects. In this work, most patients showed a significant viral load reduction during MCT and an excellent immunovirological evolution was shown once the subsequent cART was started after MCT; again, discordance rates were found between MCT and different tropism methods, similar to those found in treatment-experienced patients.2,5,6 Unfortunately, the review by Woollard and Kanmogne1 was accepted for publication just before the publication of this work, so they probably did not have time to include our data in their study. Additionally, Woollard and Kanmogne consider that MCT cannot be used in naive HIV-infected subjects based on data from Hernandez-Novoa et al,4 because these authors concluded that this clinical test cannot be used as a surrogate marker of viral tropism in naive patients. We agree with the conclusion of Hernandez-Novoa et al, since MCT is not a surrogate marker of viral tropism but a clinical test based on the virological response to a short-term exposure to the drug, and provides discordant results with different tropism assays as previously reported.2,5,6 Hernandez-Novoa et al show that patients with R5 or dual/mixed viral tropism according to Trofile® have similar virological responses to maraviroc monotherapy, reflecting the previously described discordance between the clinical approach and the phenotypic tropism method, as expected. Analyzing their data, we can see that 32/37 (85%) of their patients had virological response according to MCT (viral load reduction >1 log RNA copies/mL) while 5/37 (15%) did not, exactly the R5 and non-R5 expected percentages in HIV-1 treatment-naive patients.8 In addition, given the MCT criteria, 9/37 (24%) of the patients had discordant results with Trofile® in their study, similar to previous studies.2,5–7 Besides, unlike Hernandez-Novoa et al, in these mentioned studies we performed a follow-up of the patients proving the safety of the test according to the excellent immunovirological evolution after long-term cART started after MCT. Therefore, we consider that a misclassification by Trofile® and genotypic methods would be the more plausible explanation for the discordances observed with the virological response during maraviroc monotherapy exposure, probably due to the presence of low-level X4 variants with no clinical relevance. Taken altogether, we think that MCT remains a very promising strategy to decide maraviroc prescription in HIV-infected patients, both treatment-experienced and -naive subjects, independent of the viral tropism result once the presence of low-level X4 variants seem to be clinically irrelevant.