Comparative Performance Assessment of Novel Fluorescence Immunoassay POCTs for Measuring Circulating Levels of Vitamin-D.

Vitamin D (Vit D) is a fat-soluble molecule acting like a hormone, and it is involved in several biological mechanisms such as gene expression, calcium homeostasis, bone metabolism, immune modulation, viral protection, and neuromuscular functions. Vit D deficiency can lead to chronic hypocalcemia, hyperparathyroidism, and many other pathological conditions; in this context, low and very low levels of 25-hydroxy-vitamin D (25-OH-D) were found to be associated with an increased risk of COVID-19 infection and the likelihood of many severe diseases. For all these reasons, it is important to quantify and monitor 25-OH-D levels to ensure that the serum/blood concentrations are not clinically suboptimal. Serum concentration of 25-OH-D is currently the main indicator of Vit D status, and it is currently performed by different assays, but the most common quantitation techniques involve immunometric methods or chromatography. Nevertheless, other quantitation techniques and instruments are now emerging, such as AFIAS-1® and AFIAS-10® (Boditech and Menarini) based on the immunofluorescence analyzer, that guarantee an automated system with cartridges able to give quick and reliable results as a point-of-care test (POCT). This work aims to compare AFIAS-1® and AFIAS-10® (Boditech and Menarini) Vit D quantitation with Ultra High-Performance Liquid Chromatography coupled with tandem mass spectrometry that currently represents the gold standard technique for Vit D quantitation. The analyses were performed in parallel on 56 samples and in different conditions (from fresh and frozen plasma) to assess the reliability of the results. Any statistically significant differences in methods, the fixed error, and the error proportional to concentration were reported. Results obtained in all conditions showed a good correlation between both AFIAS® instruments and LC-MS/MS, and we can affirm that AFIAS-1® and AFIAS-10® are reliable instruments for measuring 25-OH-D with accuracy and in a fast manner.

Pharmacokinetics and safety of twice-daily ritonavir-boosted atazanavir with rifampicin.

BACKGROUND: Critical drug-drug interactions (DDI) and hepatotoxicity complicate concurrent use of rifampicin and protease inhibitors. We investigated whether dose escalation of atazanavir/ritonavir could safely overcome the DDI with rifampicin. METHODS: DERIVE (NCT04121195, EDCTP) was a dose-escalation trial in people with HIV on atazanavir/ritonavir-based ART in Uganda. Four intensive pharmacokinetic (PK) visits were performed: PK1 300/100 mg OD (baseline); PK2 300/100 mg OD with rifampicin 600 mg; PK3 300/100 mg BID with rifampicin 600 mg OD; PK4 300/100 mg BID with rifampicin 1200 mg OD. Dolutegravir 50 mg BID throughout the study period ensured participants remained protected from subtherapeutic atazanavir concentrations. The data was interpreted with noncompartmental analysis. The target minimum concentration was atazanavir's protein-adjusted IC90 (PA-IC90), 0.014 mg/L. RESULTS: We enrolled 26 participants (23 female) with median (range) age 44 (28-61) years and weight 67 (50-75) kg. Compared with PK1, atazanavir Ctau, and AUC were significantly reduced at PK2 by 96% and 85%, respectively. The escalation to BID dosing (PK3) reduced this difference in Ctau, and AUC24 to 18% lower and 8% higher, respectively. Comparable exposures were maintained with double doses of rifampicin. Lowest Ctau during PK1, PK3, and PK4 were 12.7-, 4.8-, and 8.6-fold higher than PA-IC90, respectively, while 65% of PK2 Ctau were below the limit of quantification (0.03 mg/L), hence likely below PA-IC90. No participant developed significant elevation of liver enzymes, reported an SAE, or experienced rebound viraemia. CONCLUSIONS: Twice daily atazanavir/ritonavir during rifampicin co-administration was well-tolerated and achieved plasma concentrations above the target.

Inflammation and intracellular exposure of dolutegravir, darunavir, tenofovir and emtricitabine in people living with HIV.

AIMS: Antiretroviral (ARV) therapy reduces inflammation and immune activation in people with HIV, but not down to the levels observed in people without HIV. Limited drug penetration within tissues has been argued as a potential mechanism of persistent inflammation. Data on the inflammation role on ARV plasma/intracellular (IC) pharmacokinetics (PK) through to expression of cytochrome P450 3A/membrane transporters are limited. The aim of this study was to investigate the correlation between inflammation markers (IM) and plasma/IC PK of ARV regimen in HIV-positive patients. METHODS: We included ART-experienced patients switching to three different ARV regimens. Plasma and IC ARV drug concentration means at the end of dosing interval (T0 ), IM on samples concomitantly with ARV PK determination: sCD14, CRP, IL-6 and LPS were analysed. RESULTS: Plasma and IC drug concentrations were measured in 60 samples. No significative differences between CRP, sCD14, IL-6 and LPS values in the three arms were observed. A significant inverse correlation between tenofovir plasma concentration and sCD14 (rho = -0.79, P < .001), and between DRV IC/plasma ratio and Log10 IL-6 concentrations (rho = -0.36, P = .040), and a borderline statistically significant positive trend between DRV plasma concentration and sCD14 (rho = 0.31, P = .070) were suggested. Furthermore, a borderline statistically significant inverse trend between DTG IC concentrations and sCD14 (rho = -0.34, P = .090) was observed in 24 patients on DTG-based triple therapy. CONCLUSIONS: Our preliminary data support the hypothesis of lower DRV and DTG IC concentrations and lower TFV plasma exposure in patients with higher plasma IM suggesting an interplay between HIV drug penetration and persistent inflammation in cART-treated HIV-positive patients.

The Effect of Rifampicin on Darunavir, Ritonavir, and Dolutegravir Exposure within Peripheral Blood Mononuclear Cells: a Dose Escalation Study.

Ritonavir-boosted darunavir (DRV/r) and dolutegravir (DTG) are affected by induction of metabolizing enzymes and efflux transporters caused by rifampicin (RIF). This complicates the treatment of people living with HIV (PLWH) diagnosed with tuberculosis. Recent data showed that doubling DRV/r dose did not compensate for this effect, and hepatic safety was unsatisfactory. We aimed to evaluate the pharmacokinetics of DRV, ritonavir (RTV), and DTG in the presence and absence of RIF in peripheral blood mononuclear cells (PBMCs). PLWH were enrolled in a dose-escalation crossover study with 6 treatment periods of 7 days. Participants started with DRV/r 800/100 mg once daily (QD), RIF and DTG were added before the RTV dose was doubled, and then they received DRV/r 800/100 twice daily (BD) and then 1,600/200 QD or vice versa. Finally, RIF was withdrawn. Plasma and intra-PBMC drug concentrations were measured through validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. Seventeen participants were enrolled but only 4 completed all study phases due to high incidence of liver toxicity. Intra-PBMC DRV trough serum concentration (Ctrough) after the addition of RIF dropped from a median (interquartile range [IQR]) starting value of 261 ng/mL (158 to 577) to 112 ng/mL (18 to 820) and 31 ng/mL (12 to 331) for 800/100 BD and 1,600/200 QD DRV/r doses, respectively. The DRV intra-PBMC/plasma ratio increased significantly (P = 0.003). DTG and RIF intra-PBMC concentrations were in accordance with previous reports in the absence of RIF or DRV/r. This study showed a differential impact of enzyme and/or transporter induction on DRV/r concentrations in plasma and PBMCs, highlighting the usefulness of studying intra-PBMC pharmacokinetics with drug-drug interactions. (This study has been registered at ClinicalTrials.gov under registration no. NCT03892161.).

Role of plasmatic and urinary concentration of tenofovir disoproxil fumarate in a cohort of patients affected by chronic hepatitis B.

The aim of this study was to evaluate plasmatic and urinary therapeutic drug monitoring (TDM) of tenofovir disoproxil fumarate (TDF) in a cohort of patients with chronic hepatitis B (CHB). In 68 enrolled patients, the estimated glomerular filtration rate (eGFR) was 68 mL/min in naive subjects, while in adefovir dipivoxil (ADV)-pretreated patients, it was 55.5 mL/min (p < 0.001). The HBV E genotype was associated with lower TDF levels (ß = -0.698, p < 0.001). The urinary TDF concentration was associated with ADV pretreatment (ß = 0.829, p < 0.001). Determination of urinary concentrations of TDF may be useful in the clinical management of older CHB patients and those with previous treatment with ADV.

Monthly Increase in Vitamin D Levels upon Supplementation with 2000 IU/Day in Healthy Volunteers: Result from "Integriamoci", a Pilot Pharmacokinetic Study.

Vitamin D (VD) is a calcium- and phosphate-controlling hormone used to treat bone disorders; yet, several other effects are progressively emerging. VD deficiency is highly prevalent worldwide, with suboptimal exposure to sunlight listed among the leading causes: oral supplementation with either cholecalciferol or calcitriol is used. However, there is a scarcity of clinical studies investigating how quickly VD concentrations can increase after supplementation. In this pilot study, the commercial supplement ImmuD3 (by Erboristeria Magentina®) was chosen as the source of VD and 2000 IU/day was administered for one month to 21 healthy volunteers that had not taken any other VD supplements in the previous 30 days. Plasma VD levels were measured through liquid chromatography coupled to tandem mass spectrometry after 7, 14, and 28 days of supplementation. We found that 95% of the participants had insufficient VD levels at baseline (<30 ng/mL; median 23.72 ng/mL; IQR 18.10-26.15), but after 28 days of supplementation, this percentage dropped to 62% (median 28.35 ng/mL; IQR 25.78-35.20). The median increase in VD level was 3.09 ng/mL (IQR 1.60-5.68) after 7 days and 8.85 ng/mL (IQR 2.85-13.97F) after 28 days. This study suggests the need for continuing VD supplementation and for measuring target level attainment.

Low Tenofovir Plasma Exposure in HIV Oral Pre-exposure Prophylaxis Recipients with Gastrointestinal Disorders.

Four pre-exposure prophylaxis (PrEP) users with gastro-intestinal disorders (sleeve gastrectomy, terminal ileitis, celiac disease or chronic diarrhea) and receiving oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) were included. Despite a self-reported high adherence, trough plasma tenofovir concentrations (after a supervised intake) were significantly lower than those observed in PrEP recipients without gastrointestinal disorders [21 (±9.1) vs. 138 (±85) ng/mL]. PrEP users with gastrointestinal disorders may need increased TDF doses or alternative prophylactic measures.

Medication burden and clustering in people living with HIV undergoing therapeutic drug monitoring.

AIM: People living with HIV (PLWH) have a high burden of comorbidities and concomitant medication use. The aim of this study was to analyse the prevalence, predictors and patterns of polypharmacy (PP) in a large therapeutic drug monitoring (TDM) registry. METHODS: We searched our TDM registry and categorized co-medications into 26 drug classes. We included patients with at least one medication recorded: PP and severe polypharmacy (sPP) were defined as the concomitant use of ≥5 or ≥10 nonantiretroviral/nonantitubercular drugs. Multivariable binary logistic analysis were conducted for identifying PP/sPP predictors. A hierarchical average-linkage cluster analysis was performed among drug classes. RESULTS: We included 2432 participants (1158 PLWH) aged 49.6 years (± 14.4) in the 2016-2020 period. A higher number of concomitant medications (4 vs 3.1, P < .001) and a higher prevalence of PP (26.1% vs 21.8%, P = .015) were recorded in controls. At multivariable binary logistic analysis older age, female gender and HIV-positive serostatus (P = .015) were independent predictors of PP; older age and year of inclusion were independent predictors of sPP. Cluster analysis showed that patients receiving oral drug for type 2 diabetes have a high probability of receiving several other drugs; a cluster of co-medications was observed with opioids, diuretics and central nervous system-affecting drugs. CONCLUSION: We observed a moderately high prevalence of polypharmacy in middle-aged PLWH: advanced age and female gender were associated with the greatest prevalence. The observation of co-medication clusters suggests groups of comorbidities but also identifies groups of patients at risk of similar drug-to-drug interactions.

Real-life study on the pharmacokinetic of remdesivir in ICU patients admitted for severe COVID-19 pneumonia.

Remdesivir is one of the most encouraging treatments against SARS-CoV-2 infection. After intravenous infusion, RDV is rapidly metabolized (t1/2 = 1 h) within the cells to its active adenosine triphosphate analogue form (GS-443902) and then it can be found in plasma in its nucleoside analogue form (GS-441524). In this real-life study, we describe the remdesivir and GS-441524 concentrations at three time points in nine ICU patients, through a validated ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method. The observed data confirmed the very rapid conversion of RDV to its metabolite and the quite long half-life of GS-441524. The mean Cmin , Cmax and AUC0-24 , were < 0.24 ng/mL and 122.3 ng/mL, 2637.3 ng/mL and 157.8 ng/mL, and 5171.2 ng*h/mL and 3676.5 ng*h/ml, respectively, for RDV and GS-441524. Three out of nine patients achieved a Cmax  > 2610 ng/mL and 140 ng/mL and AUC0-24  > 1560 ng*h/mL and 2230 ng*h/mL for RDV and GS-441524, respectively. The mean t1/2 value for GS-441524 was 26.3 h. Despite the low number of patients, these data can represent an interesting preliminary report on the variability of RDV and GS-441524 concentrations in a real-life ICU setting.

Development and validation of a UHPLC-MS/MS method for quantification of the prodrug remdesivir and its metabolite GS-441524: a tool for clinical pharmacokinetics of SARS-CoV-2/COVID-19 and Ebola virus disease.

BACKGROUND: Remdesivir has received significant attention for its potential application in the treatment of COVID-19, caused by SARS-CoV-2. Remdesivir has already been tested for Ebola virus disease treatment and found to have activity against SARS and MERS coronaviruses. The remdesivir core contains GS-441524, which interferes with RNA-dependent RNA polymerases alone. In non-human primates, following IV administration, remdesivir is rapidly distributed into PBMCs and converted within 2 h to the active nucleoside triphosphate form, while GS-441524 is detectable in plasma for up to 24 h. Nevertheless, remdesivir pharmacokinetics and pharmacodynamics in humans are still unexplored, highlighting the need for a precise analytical method for remdesivir and GS-441524 quantification. OBJECTIVES: The validation of a reliable UHPLC-MS/MS method for remdesivir and GS-441524 quantification in human plasma. METHODS: Remdesivir and GS-441524 standards and quality controls were prepared in plasma from healthy donors. Sample preparation consisted of protein precipitation, followed by dilution and injection into the QSight 220 UHPLC-MS/MS system. Chromatographic separation was obtained through an Acquity HSS T3 1.8 µm, 2.1 × 50 mm column, with a gradient of water and acetonitrile with 0.05% formic acid. The method was validated using EMA and FDA guidelines. RESULTS: Analyte stability has been evaluated and described in detail. The method successfully fulfilled the validation process and it was demonstrated that, when possible, sample thermal inactivation could be a good choice in order to improve biosafety. CONCLUSIONS: This method represents a useful tool for studying remdesivir and GS-441524 clinical pharmacokinetics, particularly during the current COVID-19 outbreak.

The effect of vitamin D pathway genes and deferasirox pharmacogenetics on liver iron in thalassaemia major patients.

Monitoring and treating iron overload is crucial in transfusion-dependent thalassaemia patients. Liver stiffness measurement by transient elastography and T2* magnetic resonance imaging represent non-invasive ways to evaluate the adequacy of the iron chelation treatment. We explored the role of single nucleotide polymorphisms involved in vitamin D metabolism, transport and activity, and in deferasirox metabolism on liver iron burden parameters. One-hundred and five beta-thalassaemia patients, treated with deferasirox, have been enrolled. Drug plasma Ctrough and AUC were measured by a HPLC-UV method. Allelic discrimination was performed by real-time PCR. Age, UGT1A1-364 CT/TT and CYP27B1 -1260 GT/TT positively predicted liver stiffness values. Deferasirox dose and serum ferritin negatively predicted T2* data, whereas age and CYP2D6 1457 GG genotype positively influenced these values. The discoveries of this research may be useful for personalized medicine and the proposed method could be applied in patients with hereditary hemochromatosis and myelodysplastic syndromes.

Daptomycin Plasma and CSF Levels in Patients with Healthcare-Associated Meningitis.

BACKGROUND: There are currently few data concerning the cerebrospinal fluid (CSF) penetration of daptomycin in patients with healthcare-associated meningitis. This study aims (1) to better characterize the pharmacokinetics of daptomycin in humans during a 7-day intravenous (IV) therapy course, and (2) to study the penetration of daptomycin in the CSF after IV infusion at the dose of 10 mg/kg. RESULTS: In this prospective observational study, we enrolled nine patients with an implanted external ventricular drainage and a diagnosis of a healthcare-associated meningitis. Daptomycin was administered at 10 mg/kg for a maximum of 7 days. The pharmacokinetic of daptomycin was studied using a two-compartment population/pharmacokinetic (POP/PK) model and by means of a nonlinear mixed effects modeling approach. A large inter-individual variability in plasma area under the curve (Range: 574.7-1366.3 h mg/L), paralleled by high-peak plasma concentration (Cmax) (all values > 60 mg/L), was noted. The inter-individual variability of CSF-AUC although significant (range: 1.17-6.81 h mg/L) was narrower than previously reported and with a late occurrence of CSF-Cmax (range: 6.04-9.54 h). The terminal half-life between plasma and CSF was similar. tmax values in CSF did not show a high inter-individual variability, and the fluctuations of predicted CSF concentrations were minimal. The mean value for daptomycin penetration obtained from our model was 0.45%. CONCLUSIONS: Our POP/PK model was able to describe the pharmacokinetics of daptomycin in both plasma and CSF, showing that daptomycin (up to 7 days at 10 mg/kg) has minimal penetration into central nervous system. Furthermore, the observed variability of AUC, tmax and predicted concentration in CSF was lower than what previously reported in the literature. Based on the present findings, it is unlikely that daptomycin could reach CSF concentrations high enough to have clinical efficacy; this should be tested in future studies.

Role of CYP1A1, ABCG2, CYP24A1 and VDR gene polymorphisms on the evaluation of cardiac iron overload in thalassaemia patients.

OBJECTIVES: Iron-burden-induced arrhythmia and heart failure are among the leading causes of morbidity and mortality in ß-thalassaemia major patients. T2* cardiac magnetic resonance remains the only reliable noninvasive method for the heart iron excess assessment. We explored the role of single nucleotide polymorphisms involved in vitamin D metabolism, transport and activity and in deferasirox (DFX) metabolism on cardiac iron burden. PATIENTS AND METHODS: One hundred and five ß-thalassaemia patients, treated with DFX, were enrolled in the present study. Drug plasma Ctrough was measured by a high-performance liquid chromatography-ultraviolet method. Allelic discrimination was carried out using the real-time PCR. RESULTS: CYP1A1*1189 CC, ABCG2 421 GA, CYP24A1 8620 GG and VDR TaqI CC single nucleotide polymorphisms influenced T2* values. Age, serum ferritin, ABCG2 421 GA, ABCG2 1194 +928 TC/CC, CYP24A1 22776 TT and VDR TaqI TC/CC were retained in linear regression model. CONCLUSION: Our results suggested, for the first time, the role of DFX and vitamin D pharmacogenetics on cardiac iron overload.

Pharmacogenetics of the anti-HCV drug sofosbuvir: a preliminary study.

Background: Sofosbuvir is a potent nucleotide HCV NS5B polymerase inhibitor that is also a P-glycoprotein (encoded by the ABCB1 gene) and breast cancer resistance protein (encoded by the ABCG2 gene) substrate. Concerning previous anti-HCV therapies, pharmacogenetics had a significant impact, particularly considering the association of interleukin28B polymorphisms with dual-therapy (ribavirin + pegylated IFN) outcomes. Objectives: In this work, we investigated the association between sofosbuvir and its prevalent metabolite (GS-331007) plasma concentrations at 1 month of therapy and genetic variants (SNPs) in genes encoding transporters and nuclear factors (ABCB1, ABCG2 and HNF4α) related to sofosbuvir transport. Patients and methods: Allelic discrimination was performed through real-time PCR, whereas plasma concentrations were evaluated through liquid chromatography. One hundred and thirteen patients were enrolled. Results: Sofosbuvir concentrations were below the limit of quantification since the drug was converted into its GS-331007 metabolite. ABCB1 2677 G>T (P = 0.044) and HNF4α 975 C>G (P = 0.049) SNPs were associated with GS-331007 metabolite plasma concentrations. In linear multivariate analysis, liver stiffness, insulin resistance, baseline haemoglobin and haematocrit and SNPs in the ABCB1 gene (3435 CT/TT and 1236 TT genotypes) were significant predictors of GS-331007 concentrations. Furthermore, we performed sub-analyses considering the anti-HCV concomitant drug and HCV genotype, identifying specific polymorphisms associated with GS-331007 plasma concentrations: ABCB1 3435 C>T and HNF4α975 C>G in patients treated with daclatasvir, ABCB1 2677 G>T with ledipasvir and ABCB1 3435 C>T, ABCB1 2677 G>T, ABCG2 421 C>A and ABCG2 1194 + 928 C>A with ribavirin. Conclusions: In this study we suggested sofosbuvir GS-331007 metabolite plasma levels were affected by variants in the ABCB1 and HNFα genes.

Therapeutic drug monitoring of voriconazole for treatment and prophylaxis of invasive fungal infection in children.

Voriconazole therapeutic drug monitoring is not consistently recommended due to its high interpatient and intrapatient variability. Here, we aimed to describe our experience with voriconazole for treatment and prophylaxis of invasive fungal infections in paediatric patients. A fully validated high-performance liquid chromatography-mass spectrometry method was used to quantify voriconazole concentration in plasma, at the end of dosing interval. A high interindividual variability was shown. We enrolled 237 children, 83 receiving intravenous and 154 oral voriconazole. A positive correlation between drug dose and drug plasma exposure was observed. Considering intravenous route, patients with higher serum creatinine had higher voriconazole concentrations; a positive correlation was found among drug exposure and age. Sex significantly influenced drug levels: males had higher median drug concentrations than females (P < 0.001). Close voriconazole pharmacokinetics monitoring should help individualize antifungal therapy for children.

Therapeutic drug monitoring-guided definition of adherence profiles in resistant hypertension and identification of predictors of poor adherence.

AIMS: Arterial hypertension is an important cardiovascular risk factor. A substantial proportion of patients show resistance to antihypertensive treatment but poor adherence to medication regimens is also a significant cause of treatment failure. In this context, therapeutic drug monitoring (TDM) could be useful. The objective of this study was to assess adherence to treatment in patients with resistant hypertension by TDM and to identify parameters that predict nonadherence. METHODS: Liquid chromatography tandem mass spectrometry was used to quantify a wide panel of antihypertensive drugs in human plasma to assess treatment compliance. Associations between TDM-determined adherence profiles, self-reported adherence and other patient-related clinical, anthropometric or demographic features were evaluated as potentially useful pre-TDM predictors of poor adherence. RESULTS: TDM was performed on 50 patients with suspected resistant hypertension: 24% of patients partially complied to treatment and 18% were nonadherent. No concordance was observed with questionnaire results, while nonadherence was associated with high diastolic blood pressure, high heart rate, previous onset of stroke and previous use of invasive treatments, including renal denervation or baroreceptor stimulation. CONCLUSIONS: This evidence highlights the high prevalence of poor adherence in patients with resistant hypertension and the need for caution in using invasive approaches. These preliminary data require validation in a larger cohort, to confirm the need for TDM in routine clinical practice.

Role of ribavirin in the treatment of hepatitis C virus-associated mixed cryoglobulinemia with interferon-free regimens.

Mixed cryoglobulinemia (MC) is the most common extrahepatic manifestation of chronic hepatitis C (CHC), with the presence of symptoms in 10-15% of cases. There have been encouraging data regarding immunological and clinical responses in patients treated with the novel combinations of direct-acting antivirals (DAAs), but the role of ribavirin (RBV) in the treatment of MC has not yet been demonstrated. We prospectively enrolled 132 patients affected by MC and CHC, and virological, immunological and clinical responses were evaluated at 12 weeks after completion of treatment. All subjects were treated with interferon (IFN)-free regimens according to clinical guidelines, with or without RBV. All patients achieved a virological response. A complete immunological response (CR) was observed in 71 subjects (53.8%), a partial response in 44 (33.3%), and no response in 17 (12.8%). Ten patients showed a complete resolution of symptoms (7.6%), and 31 showed a significant improvement (23.5%). CR was significantly higher in patients taking RBV (71.1 vs. 44.8%, p < 0.001) and in treatment-naïve patients (62.5 vs. 43.3%, p < 0.001). In logistic regression analysis, duration of HCV infection of less than 20 years (OR 2.448; 95% IC 1.335-6.202; p = 0.019), treatment-naïve status (OR 2.885; 95% IC 1.404-9.660; p = 0.025) and the use of RBV (OR 6.961; 95% IC 3.912-26.885; p < 0.001) were predictors of CR. In MC patients, IFN-free regimens are effective and well tolerated, and RBV seems to significantly increase the immunological response and promote a decline in cryocrit.

Daclatasvir Plasma Levels in a Cohort of Patients with Hepatitis C Virus Infection Taking Methadone: A Prospective Analysis.

Backround: The effect of methadone (MET) during therapy with novel direct-acting antiviral agents is still not fully understood. Currently, no data are available about the influence of MET on daclatasvir (DCV) plasma levels in patients affected by chronic hepatitis C (CHC). The aim of this study was to assess the DCV plasma concentrations in patients treated with sofosbuvir (SOF) plus DCV, with or without ribavirin (RBV) and with or without MET. METHODS: In this analysis, 47 patients were included, treated consecutively with SOF + DCV ± RBV for 24 weeks, from May to October 2015; 22 (46.8%) received MET substitutive therapy. RESULTS AND CONCLUSION: We found a significant difference in DCV levels at 2 weeks and 1 month: 150 ng/mL in patients without MET and 313 ng/mL with MET at 2 weeks (p < 0.001), 149 and 279 ng/mL at 1 month (p = 0.006). DCV levels were lower in cirrhotic patients (p < 0.001); among cirrhotic patients we also evidenced higher DCV concentrations in patients receiving MET at 2 weeks, 1 and 2 months (p < 0.001, p = 0.005, and p = 0.031, respectively). In multivariate analysis, the only predictive factor associated with DCV plasma levels was the presence of MET. The reason for this increased DCV exposure is unclear; on the clinical side, we have not observed significant adverse events related to the reduction or increase of MET plasma levels. The administration of MET in patients with advanced fibrosis or cirrhosis leads to an early increase of DCV plasma level without significant clinical effects or toxicity.