The use of trough ribavirin concentration to predict sustained virological response and haematological toxicity in HIV/HCV-co-infected patients treated with ribavirin and pegylated interferon

OBJECTIVES

To study the association between trough ribavirin concentration (C(trough)) with sustained virological response (SVR) and haemoglobin (Hb) decrease in HIV/hepatitis C virus (HCV)-co-infected (HIV+/HCV+) patients treated with anti-HCV therapy.

METHODS

HIV+/HCV+ patients treated with ribavirin and pegylated interferon were prospectively evaluated. Qualitative and quantitative HCV-RNA, Hb levels and ribavirin C(trough) were measured at baseline and weeks 2, 4, 12, 24, 36 and 48 during therapy. HCV-RNA was also measured at 24 weeks after the end of therapy. Efficacy analysis was performed on patients with a definitive virological outcome (SVR, relapser and non-responder), whereas for toxicity analysis, dropouts were considered until the last available observation.

RESULTS

Fifty-two patients (54.7% with genotype 1 or 4) were included. Overall, no correlation between ribavirin C(trough) and early virological response (EVR) nor SVR was found. However, in patients with genotype 1 or 4, ribavirin C(trough) was independently associated with EVR (P = 0.036) and SVR (P = 0.046). A ribavirin C(trough) cut-off of 1600 ng/mL was found to be associated with both EVR (chi(2) = 5.69, P = 0.028) and SVR (chi(2)=4.2, P = 0.04). Higher ribavirin C(trough) correlated with Hb decrease (R = -0.361, P = 0.009) and was independently associated with an Hb decrease of >4 g/dL (P = 0.009). Receiver operating characteristic (ROC) analysis indicated that a ribavirin C(trough) of >2300 ng/mL was associated with an Hb decrease of >4 g/dL (chi(2) = 8.08, P = 0.01).

CONCLUSIONS

Our study confirmed a relationship between ribavirin exposure and both efficacy and toxicity. Moreover, we found ribavirin C(trough) cut-offs for both SVR in genotypes 1 and 4 and overall haematological toxicity. These findings deserve further clinical evaluation.

Therapeutic drug monitoring of boosted PIs in HIV-positive patients: undetectable plasma concentrations and risk of virological failure

Background

Therapeutic drug monitoring (TDM) of antiretroviral drugs is performed in selected HIV-positive patients. The aim of this study was to estimate the prevalence of undetectable plasma concentrations of ritonavir and boosted PIs and to evaluate the association between those and the 48 week risk of virological failure.

Methods

A TDM registry study and a retrospective follow-up study were conducted. Plasma concentrations were measured through validated methods. According to PI and ritonavir concentrations, patients were stratified as adherent, partially non-adherent or non-adherent. Virological outcome was evaluated 48 weeks afterwards.

Results

The TDM registry study included 2468 samples collected from 723 patients (68.1% male, median age 43.5 years). Eighty-seven samples (3.5%, 74 patients) and 68 samples (2.8%, 52 patients) were in the partially non-adherent and non-adherent groups, respectively; more patients on atazanavir/ritonavir (7.9%) versus darunavir/ritonavir (2% twice daily and 1.9% once daily) and lopinavir/ritonavir (1.5%; P  <   0.001) were observed in the partially non-adherent group. Two hundred and ninety patients were included in the follow-up study (64.1% male, median age 40 years). Patients in the adherent group had a higher chance of viral control [81.9% (167/204)] versus the partially non-adherent group and the non-adherent group [71.7% (33/46) and 53.1% (17/32), respectively; P  =   0.001]. Based on multivariate analysis, baseline HIV RNA >50 copies/mL ( P  <   0.001), genotypic susceptibility score ≤2 ( P  =   0.001), lower nadir CD4 cell count ( P  =   0.003) and not being in the adherent group ( P  =   0.029) were independent predictors of HIV RNA >50 copies/mL at 48 weeks.

Conclusions

The measurement of PI and ritonavir plasma levels can uncover incomplete compliance with treatment; TDM may represent a useful tool for identifying patients in need of adherence-promoting interventions.

Efficacy, tolerability and virological consequences of long-term use of unboosted atazanavir plus 2 NRTIs in HIV-infected patients

PURPOSE

Switch to unboosted atazanavir (ATV) is an attractive option due to convenience and tolerability in HIV-positive patients. With limited available data we investigated the determinants of long-term efficacy and the consequences of virological failure of unboosted atazanavir-based regimens.

METHODS

Retrospective analysis in two Italian large outpatient clinics including demographic, immunovirological, resistance and pharmacokinetic data.

RESULTS

249 patients receiving atazanavir (400 mg once-daily) plus 2 NRTIs were included; 163 were males (65.5%) and median age was 47 years (42-51.5). Median CD4+ T-cell count was 396/uL (261-583); 146 (58.6%) presented a viral load < 50 copies/mL. Over a median follow up of 157 weeks (106-203) 193 patients (77.5%) were still on treatment with 10 (4%) and 2 (0.8%) stopping for virological failure or toxicity, respectively. Ten patients with virological failure presented newly selected resistance associated mutations (RAMs) for NRTIs (2/10) or ATV (4/10, one I50L). Total cholesterol and triglycerides showed significant decreases at 48 [-4 mg/dL and -41 mg/dL] and 96 weeks [-14 mg/dL and -54 mg/dL] as compared to baseline. At multivariate analysis a genotypic sensitivity score ≤ 1, atazanavir RAMs > 1 and suboptimal adherence were independently associated with virological failure; in lamivudine/emtricitabine-treated patients the presence of M184V (without other NRTI RAMs) was not associated with virological failure.

CONCLUSION

Unboosted-atazanavir containing regimens were efficacious (with uncommon virological failures) and well-tolerated (with improvements in lipid profile over time) treatments in HIV-positive patients. Isolated M184V in lamivudine/emtricitabine recipients was not associated with higher failure rates supporting the use of functional ATV-based dual therapies as maintenance strategies.

Tenofovir disoproxil fumarate discontinuation for renal outcomes: any room for treatment personalization?

Tenofovir disoproxil fumarate (TDF) is a very effective antiviral drug that has been associated with tubular dysfunction. The aim of this study was to analyze the demographic, pharmacokinetic, and pharmacogenetic variables associated with TDF discontinuation for renal outcomes in stable HIV-positive patients using multivariable analyses. Three hundred and four patients were included (73% male, with median age and eCrCl of 45.3 years and 90.9 mL/min, respectively). After a median follow-up of 28.3 months, 27 patients discontinued TDF for renal adverse events [persistent urinary abnormalities (n = 21) or eCrCl < 60 mL/min (n = 6)] providing an incidence of 3.77 events per 100 patient-year. The probability of TDF discontinuation was higher with several features (male gender, older age, not Caucasians ancestry, absence of intravenous drug abuse, protease inhibitors, previous indinavir, HCV-positivity, lower CD4 cell count, detectable HIV-RNA, lower eCrCl, spot-urine proteinuria) and higher tenofovir concentrations but not genetic variants. Tenofovir plasma concentrations were prognostic of TDF discontinuation for renal adverse events suggesting that dose-adjustment may be warranted for long-term safety.

Sex-specific fat mass ratio cutoff value identifies a high prevalence of cardio-metabolic disorders in people living with HIV

BACKGROUND AND AIMS

HIV-associated lipodystrophy syndrome (HALS) contributes to the increased cardiovascular risk connoting people living with HIV (PLHIV). HALS recognition, based on clinical ground, may be inaccurate urging an objective instrumental diagnosis. The aim of this study is to search for the DXA-derived fat mass ratio (FMR) threshold, among those suggested for the diagnosis of HALS, able to identify PLHIV at high cardiovascular risk.

METHODS AND RESULTS

In a cross-sectional analysis of 101 PLHIV (age 53 ± 11 years, men 55%) and 101 age- and sex-matched uninfected controls, DXA-derived FMR and anthropometric as well as cardio-metabolic parameters were assessed. PLHIV showed a higher FMR (1.15 ± 0.42 vs 0.95 ± 0.18, p < 0.01) together with a greater cardio-metabolic derangement than controls, in spite of lower BMI (24.3 ± 4.3 vs 26.9 ± 4.0 kg/m², p < 0.01) and fat mass index (FMI, 6.6 ± 3.0 vs 9.2 ± 3.1 kg/m², p < 0.01). Particularly, PLHIV with HALS (n = 28), defined as those with a FMR above 1.260 and 1.329 for men and women, respectively, had a greater prevalence of type 2 diabetes mellitus (18% vs 1%), insulin resistance (68% vs 27%), hypertriglyceridemia (50% vs 29%), hypertension (61% vs 30%) and metabolic syndrome (32% vs 10%) than those without HALS (p < 0.05 for all comparisons) and controls. At multivariate analyses, FMR in PLHIV was significantly associated (p < 0.05) with fasting glucose (β [95%CI] = 0.5, [0.1-0.9]), insulin (44.6, [14.9-74.2]), HOMA-IR (1.6, [0.5-2.7]), triglycerides (1.0, [ 0.2-1.8]) and HDL-cholesterol (-2.1, [-3.9/-0.4]) levels.

CONCLUSION

Sex-specific FMR thresholds, proposed for diagnosis of HALS, could represent new indices of cardio-metabolic derangement in PLHIV.