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Intensification of a raltegravir-based regimen with maraviroc in early HIV-1 infection

Puertas, Maria C.a,*; Massanella, Martaa,*; Llibre, Josep M.b,*; Ballestero, Monicaa; Buzon, Maria J.a; Ouchi, Dana; Esteve, Annac; Boix, Jaumed; Manzardo, Christiane; Miró, Josep M.e; Gatell, Josep M.e; Clotet, Bonaventuraa,b; Blanco, Juliàa; Martinez-Picado, Javiera,f the MaraviBoost Collaborative Group

Author Information
doi: 10.1097/QAD.0000000000000066

Abstract

Introduction

HAART suppresses viral replication in treatment-naive HIV-1-infected individuals. However, despite effective long-term treatment, residual plasma viremia persists below the limit of detection of standard methodologies [1]. In addition, cell-associated HIV-1 DNA and RNA are systematically detected in blood and tissues, replication-competent virus can be recovered ex vivo from lymphocytes, immune activation and inflammation do not completely normalize, and treatment discontinuation results in almost universal viral rebound in blood [2–4]. Such persistence of HIV-1 despite HAART is likely the consequence of a reservoir of latently infected cells established early in infection and cryptic viral replication presumably occurring in pharmacological sanctuaries [5] and facilitated by cell-to-cell transmission [6].

Early treatment might limit the size of the viral reservoir [7,8]. Likewise, intensifying treatment of HAART-suppressed individuals might help to further reduce residual viral replication [9,10] and immune activation [11,12]. Therefore, it could be hypothesized that intensification of treatment in recently infected individuals starting a three-drug HAART regimen might offer additional benefits. Because most viruses establishing the latent reservoir during early infection use CCR5 as a co-receptor [13], early intensification of treatment with the CCR5-antagonist maraviroc might be of special interest. In contrast to other antiretroviral drugs, maraviroc does not need to cross the cell membrane, it does not require intracellular processing in order to exert its activity, and it is effective against viruses resistant to other drug classes [14]. In addition, maraviroc may exert anti-inflammatory activity through its ability to inhibit CCR5-mediated chemotaxis and has proven to induce greater increases in CD4+ T-cell count than efavirenz in treatment-naive patients [15].

In the present study, we aimed to test whether intensification of a preferred gold standard triple regimen (raltegravir + tenofovir/emtricitabine) with maraviroc in patients recently infected with HIV-1 could further restrict the HIV-1 reservoir established early during HIV-1 infection.

Materials and methods

Study design and participants

This prospective, open-label, randomized study (MaraviBoost study; ClinicalTrials.gov number NCT00808002) was carried out at Hospital Universitari Germans Trias i Pujol (Badalona, Spain) and Hospital Clínic de Barcelona (Barcelona, Spain). The respective Institutional Ethics Review Committees approved the protocol and all participants provided written informed consent. We screened 44 HIV-1-positive treatment-naive patients with documented seroconversion in the previous 6 months; 30 were eventually enrolled. All enrolled patients had CCR5-using viruses (assessed by Trofile; Monogram Biosciences Inc., San Francisco, California, USA). We randomly assigned 15 patients to a control arm [tenofovir/emtricitabine (300/200 mg daily, q.d.)/raltegravir (400 mg twice daily, b.i.d.)] and 15 patients to a group intensifying HAART [tenofovir/emtricitabine (300/200 mg q.d.)/raltegravir (400 mg b.i.d.)] with maraviroc (300 mg b.i.d.) for 48 weeks (+MVC arm). Samples of plasma and peripheral blood mononuclear cells (PBMCs) were collected prior to HAART initiation (baseline) and subsequently at weeks 2, 4, 12, 24, and 48 (Supplemental Digital Content 1, https://links.lww.com/QAD/A408).

Residual viremia

During the study period, viral load was monitored using NucliSENS EasyQ HIV-1 v2.0 (bioMérieux, Marcy-l’Étoile, France), with a variable detection limit of 25–50 copies/ml. Residual viremia (down to 1 copy/ml) was subsequently measured using Cobas Ampliprep/Cobas TaqMan HIV-1 Test v2.0 (Roche Molecular Systems, Inc., Branchburg, New Jersey, USA) after ultracentrifugation of 4 ml of plasma samples. Blips in plasma viral load were defined as increases to 51–200 HIV-1 RNA copies/ml if preceded and followed by determinations below 50 copies/ml.

HIV-1 DNA quantification

Genomic DNA was extracted from 6 × 106 PBMCs (QIAamp DNA Blood Mini Kit; Qiagen GmbH, Hilden, Germany); total and integrated HIV-1 DNA copies were then quantified using qPCR with internal long terminal repeat (LTR) and LTR-Alu primer-probes, respectively [9,16]. Episomal 2-LTR circles were quantified using the Qiagen Spin Miniprep Kit to extract episomal-enriched DNA from 14 × 106 PBMCs before qPCR [9]. CCR5 gene quantification was also performed by qPCR to calculate the absolute HIV-1 copy number per million cells. Serial dilutions of a 2-LTR-CCR5 plasmid [9] were used to set up the standard curve.

Analysis of lymphocyte subsets and immune activation

Flow cytometry analysis was performed in fresh blood samples throughout the study period. We used two combinations of antibodies to characterize the various lymphocyte subsets: one combination evaluated CCR5 expression in CD4+ T-cell subsets and contained antibodies to CD45RA-FITC, CD31-PE, CD38-PerCP-Cy5.5, CCR5-PE-Cy7, CD3-APC-Cy7, and CD4-APC; the other combination was used to evaluate activation of CD8+ T cells and contained antibodies to human leukocyte antigen (HLA)-DR-FITC, PD-1-PE, CD38-PerCP-Cy5.5, CD45RO-PE-Cy7, CD3-APC-Cy7, and CD8-APC (all from BD Biosciences, San Jose, California, USA). We acquired data on an LSRII flow cytometer (BD Biosciences) and performed analyses with FlowJo v9 software (Tree Star Inc., Ashland, Oregon, USA) as described elsewhere [12].

Inflammation markers

Plasma levels of several markers of inflammation, coagulation, and endothelial function were measured in cryopreserved plasma samples. D-dimer and C-reactive protein (CRP) were measured using an aggregation assay (Biokit, Lliçà d’Amunt, Spain). Soluble CD14 (sCD14; Diaclone, Besancon, France), lipoprotein-associated phospholipase A2 (Lp-PLA2, Diaclone), soluble vascular cell adhesion molecule-1 (sVCAM-1; BD Biosciences), and interleukin-6 (Diaclone) were measured in duplicate using ELISA or cytometric bead assay following the manufacturer's instructions.

Statistical analysis

We compared medians between arms using the Mann–Whitney U test, and we analyzed changes between baseline and week 48 within each arm using the signed-rank test (paired test). When residual viremia and 2-LTR-circle datasets contained values below the limit of detection, Peto–Prentice and Peto–Prentice–Wilcoxon tests were used for comparisons between and within arms, respectively. We analyzed longitudinal changes of virological and immunological parameters using nonlinear mixed effects models based on their reported dynamics after HAART initiation [1,17–19]. In all models, each parameter was assumed to have a fixed and random effect, and the response variable (y) was considered as the log10, the square root or the untransformed observed value (as appropriate). For model selection we used the Bayesian information criterion (BIC) as suggested by Wu et al.[20]. Mixed models for residual viremia and 2-LTR circles were analyzed taking into account left-censoring methods [21]. All analyses were performed with SAS 9.1 (PROC NLMIXED, SAS, Cary, North Carolina, USA) and the R package (nlme package). Figures were generated with the GraphPad Prism v5.0b Software (GraphPad Software, Inc., La Jolla, California, USA).

Results

Study population, safety, and adverse events

A total of 30 HIV-1-positive patients with documented seroconversion in the previous 6 months, and screened for CCR5-tropic viruses were enrolled. We assigned 15 patients to a control arm (tenofovir/emtricitabine/raltegravir) and 15 patients to a group intensifying HAART with maraviroc (+MVC arm) for 48 weeks The baseline characteristics of the patients in each arm (Table 1) were well balanced and similar to those of other primary infection cohorts in terms of plasma viral load and CD4+ T-cell count [7]. All individuals were men, infected with subtype B viruses mainly by homosexual intercourses, and started treatment a median of 4.3 months after infection. Clinical adverse events of mild–moderate intensity were reported in nine patients (six in the +MVC arm and three in the control arm), but none was directly related to antiretroviral treatment or caused discontinuations.

T1-5
Table 1:
Patient characteristics at baseline and at the end of the study.

Plasma viral load

Monitoring by standard methods showed that 2 weeks after initiation of treatment, plasma viral load reached undetectable values in 31% of patients in the control group and in 20% in the +MVC arm (Fig. 1a). These values rose to 71 and 57%, respectively, 4 weeks after initiation of treatment, and at the end of the study all the patients had viral loads of less than 50 copies/ml. Three patients in the +MVC group had isolated blips in plasma viremia (51, 61, and 90 copies/ml at weeks 8, 24, and 36, respectively), and one patient in the control arm had two blips (180 and 94 copies/ml at weeks 8 and 24, respectively).

F1-5
Fig. 1:
Dynamics of plasma viral load.(a) Viral load measured using standard techniques during the study period: the percentage of patients reaching HIV-1 RNA <50 copies/ml at each time point is shown. (b) Residual viremia: individual determinations and medians for each group are shown. The detection limit of this ultrasensitive quantification (1 copy/ml) was used to represent undetectable samples in the graph (solid symbols). The gray dotted line indicates the 50 copies/ml level, which is the detection limit of standard techniques. (c) Longitudinal dynamics of residual viremia upon initiation of treatment (values <1 copy/ml were censored). Colored lines represent the simulated dynamics of the model fitted (one-phase decay model followed by a plateau) and the observed data for each group are shown as circles (mean ± SEM). Viremia half-life estimates, predicted from the dynamics modeling, are shown for each group (Wald test P value). MVC, maraviroc.

To further evaluate the dynamics of viral decay after initiation of treatment, residual viremia was measured by a modification of the Cobas Ampliprep/Cobas TaqMan HIV-1 Test to determine viral loads as low as 1 HIV-1 RNA copy/ml. Results showed fast decay of viral load during the first month on treatment, reaching a final 4-log decrease after 48 weeks (Fig. 1b). Although other authors have previously modeled as many as four decay phases for plasma viral load upon initiation of HAART [22], we were unable to model the ultrarapid first decay phase (first week) and the long-term decay phase (week 48 onward). Thus, the best fit model for our data was a one-phase decay kinetics followed by a plateau [1] that revealed a faster decay rate in the control group [median half-life of 1.02 (0.87–1.22) and 1.36 days (1.18–1.60) in the control and +MVC group, respectively; P = 0.02] followed by an equivalent plateau phase in both groups (Fig. 1c). Nevertheless, no significant differences were detected in residual viremia levels between the treatment arms at the end of the study (Table 1), suggesting that MVC inhibition of viral entry results in a temporary increased extracellular viral load.

Decay in proviral DNA

The size of the proviral DNA reservoir, measured as intracellular HIV-1 DNA copies per million PBMCs, decayed progressively throughout the study period in both groups (Table 1), reaching a median fold decrease of 7.7 and 8.8 after the 48 weeks of treatment in the control and +MVC arms, respectively (P = 0.25). When these data were fitted to a two-phase decay model [1], the first decay rate was similar in both groups, with a predicted median half-life of 2.30 and 2.37 weeks in the control and +MVC arm, respectively (P = 0.88; Fig. 2a). However, the median half-life of the proviral reservoir was shorter in the +MVC group in the second decay phase [27.3 (17.4–61.1) vs. 46.7 (29.1–117.8) weeks; P = 0.08].

F2-5
Fig. 2:
Dynamics of proviral and episomal HIV-1 DNA in peripheral blood mononuclear cells.(a) Intracellular proviral DNA reservoir. Total HIV-1 DNA copies/million cells were measured in PBMCs. Circles represent observed data (mean ± SEM) for each group. Data were fitted to a two-phase decay model (colored lines). Reservoir half-lives for the first-phase and second-phase decays are shown for each group (Wald test P value). (b) Episomal HIV-1 DNA dynamics. Data from two long terminal repeat (2-LTR) circles quantification in PBMCs are shown as increments, with respect to baseline individual levels. Circles represent observed data (mean ± SEM) for each group. Dynamics of the 2-LTR data fitted to a nonlinear mixed model, which included a growth phase followed by a decay phase, is shown color-coded for each group (five patients from each arm were excluded from the dynamics model analysis because 2-LTR values at baseline were <1 copy/million cells). MVC, maraviroc; PBMC, peripheral blood mononuclear cell.

Similarly, a decay kinetics was observed for the integrated HIV-1 DNA copy number, when patients with complete longitudinal follow-up were analyzed. An overall median fold decrease of 6.7 was observed after 48 weeks of treatment, with no significant differences between the study arms (P = 0.91; data not shown).

Episomal viral DNA

2-LTR DNA circles, which are considered a surrogate marker of recent infection events, were also quantified in PBMCs. A transient increase after initiation of treatment was observed in most individuals from both study arms, probably because the integrase inhibitor raltegravir was present in both treatment regimens (Supplemental Digital Content 2, https://links.lww.com/QAD/A409). However, the 2-LTR accumulation phase in the +MVC arm resolved earlier, with greater decrements in 2-LTR circles at week 12 (P = 0.060, Mann–Whitney test) (Fig. 2b). When 2-LTR dynamics was fitted to a nonlinear mixed model including a growth phase followed by a decay phase then by a plateau [19], differences in the increase rate or plateau level were not significant between the groups (P = 0.14 and 0.19, respectively, Wald test). Nevertheless, the estimated time to reach 2-LTR copy numbers equivalent to baseline levels was shorter in the +MVC arm (5.9 vs. 14.8 weeks; Fig. 2b), suggesting that maraviroc might accelerate the control of new infection events.

Analysis of lymphocyte subsets and immune activation

The absolute counts of CD4+ T cells showed higher increases in the +MVC arm at week 12 (P = 0.011, between groups). However, the differences in increase rates did not reach statistical significance (Fig. 3a) and values were similar in both arms at the end of the study (P = 0.49, Table 1). Conversely, the decrease in absolute CD8+ T-cell counts was slower in the +MVC arm when data were fitted to a single exponential decay model (P = 0.0002, Fig. 3b), even though both arms reached a similar value at week 48 (P = 0.82, Table 1). Moreover, changes in the total lymphocyte counts (defined by CD45+ staining) from baseline showed significant differences between groups; the control group decreased lymphocyte counts, while the +MVC group showed an increasing trend (Fig. 3c). Despite these differences, the CD4+/CD8+ T-cell ratio showed similar significant gains in both groups (Fig. 3d).

F3-5
Fig. 3:
Analysis of lymphocyte subsets.(a) and (b) Dynamics of absolute counts of CD4+ and CD8+ T cells. Significant differences between groups were observed for CD4+ T cells at week 12 (indicated by an asterisk, P = 0.011, Mann–Whitney test), although the curves fitted were similar (P = 0.51 and 0.25 for the increase and plateau phase, respectively, Wald test). No differences were observed for CD8+ T cells at any time point, although the curves fitted showed significantly different decay rates. Median half-lives are shown in color for each group and comparative P value is shown in black. (c) Dynamics of the absolute number of lymphocytes (change from baseline). Final increments in the plateau phase are color-coded for each group and comparative P value (Wald test) is shown in black. (d) CD4+/CD8+ T-cell ratio. Plots show mean ± SEM values and fitted curves (first-order exponential growth/decay) for the control group (orange) and +MVC group (blue). MVC, maraviroc; NS, not significant.

In CD4+ T cells, the activation level (frequency of HLA-DR+CD38+cells) decreased during the study in both arms (P < 0.01, Table 1) but with a slower decay rate in the +MVC arm (Fig. 4a, upper panel). The co-expression of these markers in the CD8+ T-cell compartment also decreased significantly in both arms (P < 0.01, Table 1) without kinetic differences (Fig. 4a, lower panel). To test the potential interaction of maraviroc on activated cells, we analyzed CD4+ and CD8+ T cells for baseline expression of CCR5 in CD38+/− CD45RA+ and CD45RA cells, which are known to express higher CCR5 levels [23]. CD38+ cells showed significantly higher CCR5 expression in the CD4+ T-cell compartment either in the CD45RA (P = 0.018) or CD45RA+ subsets (P = 0.007, Fig. 4b, upper). No significant difference in the expression of CCR5 between CD38+ and CD38 cells was observed in CD8+ T-cells (Fig. 4b, lower). Longitudinal analysis of CCR5 expression in CD4+ and CD8+ T cells showed significant decreases in CD45RA subsets, consistent with the reported increased expression of CCR5 in viremic HIV-1-infected individuals [24]. However, no significant difference in decay rates was observed between the arms (Fig. 4c, upper and lower panels, respectively).

F4-5
Fig. 4:
Analysis of immune activation and CCR5 expression.Panel (a) Dynamics of the frequency of HLA-DR+CD38+ cells in CD45RO+ subsets of CD4+ (upper plot) and CD8+ (lower plot) T cells. When differences are statistically significant, median half-lives are shown in color for each group and P value (Wald test) is shown in black. Panel (b) The frequency of CCR5+ staining in activated cells (CD38+) and resting cells (CD38) in the CD45RA+ and CD45RA subsets was assessed at baseline in all patients. Plots show individual and median values for CD4+ cells (upper plot) and CD8+ cells (lower plot) cells. P values for significant comparisons between subsets (Mann–Whitney test) are shown. Panel (c) Dynamics of the expression of CCR5 in CD4+ cells (upper plot) and CD8+ cells (lower plot). Plots show mean ± SEM values and fitted curves (first-order exponential growth/decay) for the control group (orange) and +MVC group (blue). MVC, maraviroc; NS, not significant.

Inflammation biomarkers

Soluble markers of monocyte activation/bacterial translocation (sCD14), cardiovascular risk (Lp-PLA2 and sVCAM-1), inflammation (interleukin-6, CRP), and coagulation (D-dimer) were measured throughout the study. Significant decreases were observed in both arms for sCD14, sVCAM-1, and Lp-PLA2, while interleukin-6 levels remained constant. CRP only decreased in the +MVC arm at week 48 compared to baseline (P < 0.05). However, no differences were observed for any biomarker between groups at week 48 (Supplemental Digital Content 3, https://links.lww.com/QAD/A410).

Discussion

HIV-1 reservoirs are established early after infection, leaving a narrow ‘window of opportunity’ for potentially curative chemotherapeutic and immunotherapeutic interventions [25]. Initiation of early triple-drug-based HAART in recently HIV-1-infected patients restricts the size of the viral reservoir [7,8,26], minimizes viral evolution [27], and limits immune damage [28]. Further intensification of treatment in this context might provide additional therapeutic and immunological benefits. In this study, we show that intensification of HAART (raltegravir, tenofovir, and emtricitabine) with maraviroc in patients recently infected with HIV-1 did not significantly restrict the HIV-1 reservoir established during early HIV-1 infection. Despite a combination of four drugs from three different drug families, the potential benefits of adding maraviroc were subtle.

Although plasma viral load decreased rapidly in both study arms to achieve the same plateau after 12 weeks, decay was slightly slower in the intensification group. This could be related to the effect of maraviroc in preventing HIV-1 from entering CD4+ T cells by selectively binding to CCR5 molecules on the target cell surface. In fact, in-vitro models have suggested that entry inhibitors exhibit a class-specific redistribution effect that results in short-term increased extracellular viral load [29], which might explain transiently inflated viral load values in the +MVC arm. These observations indicate that the plasma viral load decay rate should not be used as the only measure of efficacy in maraviroc-based treatments.

Total HIV-1 DNA in PBMCs also decreased significantly immediately after initiation of treatment, but with slower kinetics than plasma viremia. The reduction kinetics of this molecular parameter during the study period was comparable with that observed in other studies wherein therapy was started during acute or early infection [7,30,31]; however, it reached lower levels than in clinical trials wherein therapy was started during the chronic phase of HIV-1 infection [32,33]. Although we found no significant difference in total HIV-1 DNA levels between groups at week 48, the decay in modeling data did not reach a plateau during the study period, indicating that initiation of treatment during early infection might help to reduce cell-associated HIV-1 DNA beyond the first year of treatment. Indeed, the faster decay rate observed in the +MVC arm during the second decay phase suggests a potential effect of intensification with maraviroc in long-term clearance of the viral reservoir. As our data reveal no differences in the first phase of decay and suggest a faster second phase decay in the +MVC arm, the increase in sampling frequency beyond week 12, and longer follow-up times, would be strongly recommended for future study designs.

The transient increase in 2-LTR circles observed in both study arms was consistent with the impact that raltegravir has by abrogating events of viral integration [9,33]. However, taking into account that viral episomes are surrogate markers of recently infected cells [34,35], the subsequent faster decrease in 2-LTR circles in the +MVC arm suggests that, despite the efficacy of a raltegravir-based triple-drug regimen in suppressing viral replication, there is still a window of opportunity for maraviroc to accelerate the control of new infection events. This possibility is also coherent with the mechanism of action of this drug at blocking viral entry.

The immunomodulatory action of CCR5 blockade by maraviroc appears to have a beneficial effect over efavirenz on the treatment of naive HIV-1-infected individuals by inducing a faster increase in CD4+ T-cell counts [15] and a faster decrease in activation and inflammatory markers [36]. Furthermore, intensification of standard HAART with maraviroc in chronic HIV-1 infection increases immune responses in the absence of major changes in CD4+ T cells [37]. In our study, few differences were observed between the arms in the parameters analyzed, most likely owing to the addition of maraviroc to a highly potent raltegravir-based regimen, which may limit the ability of maraviroc to further improve the dynamics of activation/inflammation markers. Unexpectedly, the faster increase in CD4+ T-cell counts induced by maraviroc at week 12 is not concomitant with a faster change in immune activation (assessed by the frequency of HLA-DR+CD38+ cells), which was significantly slower in the +MVC arm. This observation could be a consequence of subtle differences in viral load dynamics between arms. However, no association between plasma viral load and immune activation decay rates was noticed in the +MVC or control arms. Therefore, considering that immune activation is not restricted to HIV-1-specific cells and the higher expression levels of CCR5 in activated CD4+ T cells, our data may suggest that the immunomodulatory effect of CCR5 blockade is the main force behind differential activation dynamics, as recently suggested in immunodiscordant patients [38].

The present work also analyzed gut biopsies of four patients in the control group and three patients in the +MVC group at the end of the study. We selected the terminal ileum because previous studies had identified differences in HIV-1 burden and immune activation at this site in HIV-1-positive patients receiving suppressive HAART [39]. However, we found no major differences in the immune activation levels of cells isolated from biopsy specimens when comparing the study groups (data not shown). The interpretation of these data is hampered by the low number of samples analyzed, and the fact that the gut biopsies were taken only on termination of the study, but not before initiation of treatment.

The effect of intensifying treatment in recently infected patients starting antiretroviral treatment was recently addressed in two independent pilot clinical trials. A randomized 48-week open-label trial comparing a five-drug regimen (tenofovir/emtricitabine/boosted protease inhibitor/raltegravir/maraviroc) with a three-drug regimen (tenofovir/emtricitabine/zidovudine or boosted darunavir) initiated in patients after a median of 45 days of infection revealed no significant differences in as-treated response rates, residual plasma viremia, and markers of immune activation [40]. This observation is mostly consistent with the results from our study, in which treatment was started a median of 4.3 months after infection. Conversely, in a trial involving 15 patients who started a five-drug regimen (tenofovir/emtricitabine/efavirenz/raltegravir/maraviroc) during acute HIV-1 infection, a significant reduction in reservoir size and a partial immune restoration in the gut was observed after 24 weeks of treatment [31]. Although the study conclusions are somewhat limited by the lack of a comparator group receiving standard HAART, it is remarkable that patients started their five-drug HAART only 18 days after HIV-1 infection, suggesting that aggressive clinical interventions might have an extremely narrow window of opportunity.

Thus, although our data do not support the idea that intensification of standard HAART during early infection would lead to generalized control of the infection, it is still possible that such an intervention during acute infection results in long-term clinical benefits.

Acknowledgements

The authors thank I. Erkizia, S. Marfil, P. Cañadas, J. Carrillo, and E. García for technical support; V. Moreno de Vega for clinical assistance. The members of the MaraviBoost study group: R. Escrig, M. Larousse, I. Bravo, S. Gel, and J. Puig for clinical monitoring during the study; and R. Ayén, T. González, E. Grau and M.C. Ligero for sample processing.

Author contributions: M.C.P. and M.M. performed data acquisition, analysis, and interpretation, and wrote the manuscript; M.B., I.E., S.M., and J. Boix contributed to acquisition of data; D.O. and A.E. performed statistical data analysis; M.J.B. contributed to data analysis and interpretation, and revised the manuscript; J.M.L., C.M., J.M.M., J.M.G., and B.C. contributed to clinical study design and revised the manuscript; J. Blanco and J.M.-P. contributed to study design and data interpretation and wrote the manuscript. All authors approved the final manuscript. J. Blanco and J.M.-P. are joint senior authors on this work.

Funding: This study was supported by funding from the European Community's Seventh Framework Program [FP7/2007–2013] under the project ‘Collaborative HIV and Anti-HIV Drug Resistance Network (CHAIN)’ [grant agreement No. 223131], by the Spanish AIDS network ‘Red Temática Cooperativa de Investigación en SIDA’ [RD06/0006], by the HIVACAT program, Gala contra la sida: Barcelona 2012, and by an unrestricted grant from ViiV. J Blanco is supported by the ISCIII and the Health Department of the Catalan Government (Generalitat de Catalunya). M.J.B. and M.M. were supported by Agència de Gestió d’Ajuts Universitaris i de Recerca from Generalitat de Catalunya and the European Social Fund.

Conflicts of interest

All authors declare that they have no competing interests related to this work.

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Keywords:

early infection; HIV-1; maraviroc; raltegravir; treatment intensification; viral reservoir

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