Virological response after short-term CCR5 antagonist exposure in HIV-infected patients: frequency of subjects with virological response and associated factors

Validation of the HIV Tropism Test TROCAI Using the Virological Response to a Short-Term Maraviroc Monotherapy Exposure

TROCAI is a phenotypic tropism test developed using the virological response to a short-term exposure to maraviroc monotherapy (Maraviroc Clinical Test [MCT]). It was found that with TROCAI, a cutoff of <0.5% of dual/mixed viruses was needed to predict R5 HIV tropism. Here, we have validated TROCAI, using this cutoff, in a new cohort of 42 patients, finding a very high concordance between TROCAI and MCT (98%), and a good concordance (71 to 87%) with other genotypic/phenotypic methods.

Reduced Baseline Sensitivity to Maraviroc Inhibition Among R5 HIV-1 Isolates From Individuals With Severe Immunodeficiency

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Durability and Effectiveness of Maraviroc-Containing Regimens in HIV-1-Infected Individuals with Virological Failure in Routine Clinical Practice

INTRODUCTION

Limited data are available on the durability and effectiveness of maraviroc in routine clinical practice. We assessed the durability of maraviroc-containing regimens during a 30-month period, as well as their immunovirological and clinical efficacy, according to viral tropism in treatment-experienced individuals with viral load (VL) >50 copies/ml in the French Hospital Database on HIV.

METHODS

Virological success was defined as VL<50 copies/ml, immunological success as a confirmed increase of at least 100 CD4 cells/mm3 measured twice at least one month apart, and clinical failure as hospitalization for a non-AIDS event, an AIDS event, or death. Multivariable Cox regression models adjusted for potential confounders were used to assess the influence of viral tropism on durability, the immunovirological responses, and clinical outcome.

RESULTS

356 individuals started maraviroc with VL>50 copies/ml of whom 223 harbored R5 viruses, 44 non-R5 viruses and 89 viruses of unknown tropism. Individuals with non-R5 viruses were more likely than individuals with R5 viruses to discontinue maraviroc (75% vs 34%, p<0.0001). At 30 months, the estimated rates of virological and immunological success were respectively 89% and 51% in individuals with R5 viruses and 48% and 23% in individuals with non-R5 viruses. In multivariable analysis, non-R5 viruses were associated with a lower likelihood of both virological success (hazard ratio (HR): 0.42; 95% confidence interval (CI), 0.25-0.70) and immunological success (HR: 0.37; 95% CI, 0.18-0.77). No difference in clinical outcome was found between individuals with R5 and non-R5 viruses. The effectiveness of maraviroc-containing regimens in individuals with unknown viral tropism was not significantly different from that in individuals with R5 viruses. A limitation of the study is the absence of genotypic susceptibility score.

CONCLUSION

In this observational study, maraviroc-containing regimens yielded high rates of viral suppression and immunological responses in individuals with R5 viruses in whom prior regimens had failed.

Maraviroc Clinical Test (MCT) as an alternative tool to decide CCR5-antagonists prescription in naïve HIV-infected patients

Our aim was to analyze the virological response to a combined antiretroviral therapy started after Maraviroc Clinical Test (MCT) in naïve HIV-infected patients. Forty-one patients were exposed to MCT, based on an 8-day MVC monotherapy. If undetectability or a viral load reduction >1 log10 HIV-RNA copies/ml was achieved, a MVC-containing cART was prescribed. Forty patients showed a positive MCT; undetectability after 48weeks on cART was achieved in 34/41 (82.9%) patients. The result of MCT was compared with a genotypic tropism method and with Trofile®, showing 10.7% and 18.75% discordance rates, respectively. MCT is a reliable tool to decide CCR5-antagonists prescription, also in the naïve scenario where most patients show a virological response to MVC independently the tropism result reported by genotypic or phenotypic methods.

Virological and immunological response to antiretroviral regimens containing maraviroc in HIV type 1-infected patients in clinical practice: role of different tropism testing results and of concomitant treatments

We assessed the immunovirological response to antiretroviral regimens containing maraviroc in HIV-infected viremic patients with viral tropism predicted by different assays. We selected antiretroviral treatment-experienced HIV-1-infected patients initiating regimens containing maraviroc after different phenotypic or genotypic viral tropism assays, with at least one HIV-1 RNA determination during follow-up. Survival analysis was employed to assess the virological response as time to HIV-1 RNA <50 copies/ml and immunological response as time to a CD4 cell count increase of ≥ 100/μl from baseline. Predictors of these outcomes were analyzed by multivariate Cox regression models. In 191 treatments with maraviroc, virological response was achieved in 65.4% and the response was modestly influenced by the baseline viral load and concomitant drug activity but not influenced by the type of tropism assay employed. Immunological response was achieved in 58.1%; independent predictors were baseline HIV-1 RNA (per log10 higher: HR 1.29, 95% CI 1.05-1.60) and concomitant therapy with enfuvirtide (HR 2.05, 0.96-4.39) but not tropism assay results. Of 17 patients with baseline R5-tropic virus and available tropism results while viremic during follow-up on maraviroc, seven (41%) showed a tropism switch to non-R5 virus. A significant proportion of experienced patients treated with regimens containing maraviroc achieved virological response. The tropism test type used was not associated with immunovirological response and concomitant treatment with enfuvirtide increased the chance of immunological response. More than half of virological failures with maraviroc were not accompanied by tropism switch.

Effect of maraviroc on HIV disease progression-related biomarkers

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.

The role of genetic variants of Stromal cell-Derived Factor 1 in pediatric HIV-1 infection and disease progression

Stromal cell-Derived Factor 1 (SDF1) is the natural ligand of CXCR4, the coreceptor of HIV-1 X4 viruses. This study investigated the role of the single nucleotide polymorphism (SNP) rs1801157 (NM_000609.5:c.*519G>A) of the SDF1 gene in the natural history of mother-to-child transmission of HIV-1 and disease progression of HIV-1-infected children. The study was conducted in 428 children born to HIV-1-seropositive mothers, who had not undergone antiretroviral therapy (ART) during pregnancy, and in 120 HIV-1-infected children for whom the end-point was the onset of AIDS or the initiation of ART; 16 children developed early AIDS (<24 months of life), 13 from 24 to 84 months of age, and 14 had late AIDS (>84 months). The rs1801157 SNP was not associated with risk of perinatal infection in any genetic models tested. By contrast, this SNP influenced disease progression in a time-dependent manner. rs1801157 GA heterozygous children had a higher risk of late AIDS (HR = 6.3, 95%CI 1.9–20.7, p = 0.002) than children with the rs1801157 GG genotype. Children were studied for viral coreceptor usage at birth, after 84 months of age and/or at AIDS onset. While R5 viruses using CCR5 coreceptor were predominant at birth (94%) and at early AIDS (85%), viruses using CXCR4 coreceptor emerged during the course of infection and were detected in 49% of children older than 84 months and in 62% of late AIDS. The rs1801157 SNP did not influence the emergence of R5X4 viruses, but children with the rs1801157 GA genotype and R5X4 viruses were at significantly higher risk of late AIDS than children with rs1801157 GG genotype (OR = 8.0, 95% CI 1.2–52.2, p = 0.029). Our results indicate that the rs1801157 SNP does not influence perinatal infection, but impacts disease progression. This effect is time-dependent and linked to the coreceptor-usage of viral variants that undergo evolution during the course of HIV-1 infection.

Correlation of the virological response to short-term maraviroc monotherapy with standard and deep-sequencing-based genotypic tropism prediction methods

Genotypic tropism testing methods are emerging as the first step before prescription of the CCR5 antagonist maraviroc (MVC) to HIV-infected patients in Europe. Studies validating genotypic tests have included other active drugs that could have potentially convoluted the effects of MVC. The maraviroc clinical test (MCT) is an in vivo drug sensitivity test based on the virological response to a short-term exposure to MVC monotherapy. Thus, our aim was to compare the results of genotypic tropism testing methods with the short-term virological response to MVC monotherapy. A virological response in the MCT was defined as a ≥ 1-log(10) decrease in HIV RNA or undetectability after 8 days of drug exposure. Seventy-three patients undergoing the MCT were included in this study. We used both standard genotypic methods (n = 73) and deep sequencing (n = 27) on MCT samples at baseline. For the standard methods, the most widely used genotypic algorithms for analyzing the V3 loop sequence, geno2pheno and PSSM, were used. For deep sequencing, the geno2pheno algorithm was used with a false-positive rate cutoff of 3.5. The discordance rates between the standard genotypic methods and the virological response were approximately 20% (including mostly patients without a virological response). Interestingly, these discordance rates were similar to that obtained from deep sequencing (18.5%). The discordance rates between the genotypic methods (tropism assays predictive of the use of the CCR5 coreceptor) and the MCT (in vivo MVC sensitivity assay) indicate that the algorithms used by genotypic methods are still not sufficiently optimized.