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1.  Clinical experience with nonstandard doses ofinterferon alfa-2b and ribavirin in the treatment of chronic hepatitis C infection: A retrospective analysis 
Hepatitis C virus (HCV) infection is the most common blood-borne virus in the United States. Several mono- and combination therapies have been approved by the US Food and Drug Administration for the treatment of HCV, but their routes of administration, dosing approaches, eras of introduction, and actual use in clinical practice and resulting effectiveness have not yet been reported.
The aim of this article was to characterize clinical use and virologic response (VR) of the HCV treatments interferon alfa-2b plus ribavirin (IFN + RBV) and peginterferon alfa-2b plus ribavirin (peg-IFN + RBV).
This retrospective chart review of office-based practices in theUnited States was conducted at 200 physicians' offices across the United States. We collected data concerning dosing patterns, VR (HCV RNA load, ≤1000 IU/mL or “negative” on polymerase chain reaction qualitative analysis), and adverse events (AEs) from the medical records of a geographically diverse sample of patients receiving treatment for chronic HCV infection in the United States from July 2001 to June 2002. For efficacy assessment, factors that were statistically different at baseline were adjusted using logistic regression. Providers also reviewed the medical records for symptoms or signs consistent with HCV treatment-related AEs.
Data from the records of 675 patients (423 men, 252 women; mean [SD] age of 45.5 [8.2] years; mean [SD] body weight, 80.8 [19.4] kg) were analyzed. At baseline, the IFN + RBV treatment group (330 patients) had significantly higher percentages of black patients (22.1% vs 15.7%; P = 0.032) and patients with hepatic disease based on clinician-reported cirrhosis and liver dysfunction (18.8% vs 9.9%; P < 0.001), and a significantly lower percentage of white patients (60.3% vs 69.6%; P = 0.012) compared with the peg-IFN + RBV treatment group (345 patients). The difference in log-transformed baseline HCV RNA loads between the 2 treatment groups in this study was <1 log unit. A significantly higher percentage of IFN + RBV-treated patients compared with peg-IFN + RBV-treated patients were prescribed HCV therapy on diagnosis (37.3% vs 29.9%; P = 0.041), and the mean (SD) duration of treatment was significantly different between the 2 treatment groups (52.5 [37.0] vs 27.5 [15.0] weeks; P < 0.001). Peg-IFN + RBV was associated with a higher rate of VR compared with IFN + RBV on univariate analysis (28.5% vs 17.5%; P = 0.018). Recommended doses of peg-IFN and higher-than-recommended doses of RBV were associated with an increased likelihood of VR. Higher-than-recommended doses of peg-IFN without a concomitant increase in RBV was not associated with an increased likelihood of VR. The incidences of the 3 most commonly reported AEs in the IFN + RSV group were significantly higher compared with those in the peg-IFN + RSV group: fatigue, 217 (65.8%) versus 185 (53.6%) patients (P = 0.001); depression, 147 (44.5%) versus 120 (34.8%) (P = 0.009); and anxiety, 87 (26.4%) versus 64 (18.6%) (P = 0.014). Nausea, however, was reported in a significantly higher number of patients in the peg-IFN group compared with the IFN + RBV group (74 [21.4%] vs 51 [15.5%]; P = 0.045). The frequencies of dose modification and treatment discontinuation due to AEs were similar between the 2 treatments and were similar to or less than those reported in other studies.
In this retrospective data analysis of US office-based practicesconcerning HCV treatment, clinicians were observed to prescribe IFN + RBV at doses that differ from recommendations in the product information (PI), as well as prescribe the RBV component of peg-IFN + RBV at doses that differed from PI recommendations. Although patients treated with peg-IFN + RBV appeared to achieve higher VR compared with those treated with IFN + RBV in our analysis of data from clinical practice, peg-IFN + RBV was associated with lower VR rates compared with those reported in clinical studies.
PMCID: PMC4003805  PMID: 24790244
hepatitis C; pegylated interferon; interferon alfa-2b and ribavirin; ribavirin; dosing; outcomes
2.  Comparison of Classification Algorithms with Wrapper-Based Feature Selection for Predicting Osteoporosis Outcome Based on Genetic Factors in a Taiwanese Women Population 
An essential task in a genomic analysis of a human disease is limiting the number of strongly associated genes when studying susceptibility to the disease. The goal of this study was to compare computational tools with and without feature selection for predicting osteoporosis outcome in Taiwanese women based on genetic factors such as single nucleotide polymorphisms (SNPs). To elucidate relationships between osteoporosis and SNPs in this population, three classification algorithms were applied: multilayer feedforward neural network (MFNN), naive Bayes, and logistic regression. A wrapper-based feature selection method was also used to identify a subset of major SNPs. Experimental results showed that the MFNN model with the wrapper-based approach was the best predictive model for inferring disease susceptibility based on the complex relationship between osteoporosis and SNPs in Taiwanese women. The findings suggest that patients and doctors can use the proposed tool to enhance decision making based on clinical factors such as SNP genotyping data.
PMCID: PMC3557627  PMID: 23401685
3.  Comparison of peginterferon alfa-2a and alfa-2b for treatment of patients with chronic hepatitis C: a retrospective study using the Japanese Interferon Database 
We aimed to compare the rates of sustained virologic response (SVR) achieved with peginterferon (PEG-IFN) alfa-2a and alfa-2b in combination with ribavinin (RBV) for chronic hepatitis C, using a large database of hepatitis cases to improve the generalizability of these results.
We identified patients with chronic hepatitis C who were treated with PEG-IFN alfa-2a or alfa-2b and RBV, from the Japanese Interferon Database, between December 2009 and April 2013. This database contains the medical records of IFN treatment collected from 36 prefectures in Japan. Multivariable logistic regression analysis was used to compare SVR rates obtained with PEG-IFN alfa-2a and alfa-2b, in combination with RBV.
A total of 16,349 patients were recorded in the Japanese Interferon Database. After application of the exclusion criteria, 12,706 patients (3,578 [1,710 males, 1,868 females] on PEG-IFN alfa-2a; and 9,128 [4,652 males, 4,476 females] on PEG-IFN alfa-2b) were included in this analysis. The SVR rate in the PEG-IFN alfa-2b group was 62.0%, as compared with a rate of 55.1% in the PEG-IFN alfa-2a group (crude odds ratio =1.31; 95% confidence interval [CI]: 1.23 to 1.44). There was no significant difference in the adjusted SVR rates between the two groups (adjusted odds ratio =0.96; 95% CI: 0.88 to 1.05). Similar proportions of adverse events were observed in the two groups, with the exception of thrombocytopenia, retinopathy, and anemia.
There was no significant difference in the SVR rates and safety profile between chronic hepatitis C patients treated with the PEG-IFN alfa-2a and alfa-2b.
PMCID: PMC4283988  PMID: 25565777
sustained virologic response; HCV genotype; sustained virologic response; adverse events
4.  Modeling Viral Evolutionary Dynamics after Telaprevir-Based Treatment 
PLoS Computational Biology  2014;10(8):e1003772.
For patients infected with hepatitis C virus (HCV), the combination of the direct-acting antiviral agent telaprevir, pegylated-interferon alfa (Peg-IFN), and ribavirin (RBV) significantly increases the chances of sustained virologic response (SVR) over treatment with Peg-IFN and RBV alone. If patients do not achieve SVR with telaprevir-based treatment, their viral population is often significantly enriched with telaprevir-resistant variants at the end of treatment. We sought to quantify the evolutionary dynamics of these post-treatment resistant variant populations. Previous estimates of these dynamics were limited by analyzing only population sequence data (20% sensitivity, qualitative resistance information) from 388 patients enrolled in Phase 3 clinical studies. Here we add clonal sequence analysis (5% sensitivity, quantitative) for a subset of these patients. We developed a computational model which integrates both the qualitative and quantitative sequence data, and which forms a framework for future analyses of drug resistance. The model was qualified by showing that deep-sequence data (1% sensitivity) from a subset of these patients are consistent with model predictions. When determining the median time for viral populations to revert to 20% resistance in these patients, the model predicts 8.3 (95% CI: 7.6, 8.4) months versus 10.7 (9.9, 12.8) months estimated using solely population sequence data for genotype 1a, and 1.0 (0.0, 1.4) months versus 0.9 (0.0, 2.7) months for genotype 1b. For each individual patient, the time to revert to 20% resistance predicted by the model was typically comparable to or faster than that estimated using solely population sequence data. Furthermore, the model predicts a median of 11.0 and 2.1 months after treatment failure for viral populations to revert to 99% wild-type in patients with HCV genotypes 1a or 1b, respectively. Our modeling approach provides a framework for projecting accurate, quantitative assessment of HCV resistance dynamics from a data set consisting of largely qualitative information.
Author Summary
Hepatitis C virus (HCV) chronically infects approximately 170 million people worldwide. The goal of HCV treatment is viral eradication (sustained virologic response; SVR). Telaprevir directly inhibits viral replication by inhibiting the HCV protease, leading to high SVR rates when combined with pegylated-interferon alfa and ribavirin. Telaprevir-resistant variants may be detected in the subset of patients who do not achieve SVR with telaprevir. While the clinical impact of viral resistance is unknown, typically the telaprevir-sensitive virus re-emerges after the end of treatment due to competition between the telaprevir-sensitive and resistant variants. Previous estimates of these competition dynamics were obtained from population sequence data, which are qualitative and have a limited sensitivity of ∼20%. We sought to improve these estimates by combining these data with clonal sequence data, which are quantitative and have a sensitivity of ∼5%, and using quantitative modeling. The resulting model, which was verified with an independent data set, predicted that the median time for telaprevir-resistant variants to decline to less than 1% of the viral population was ≤1 year. Our modeling approach provides a framework for accurately projecting HCV resistance dynamics from a dataset consisting of largely qualitative information.
PMCID: PMC4138032  PMID: 25101970
5.  Impact of ribavirin dose on retreatment of chronic hepatitis C patients 
AIM: To study the efficacy and factors associated with a sustained virological response (SVR) in chronic hepatitis C (CHC) relapsing patients.
METHODS: Out of 1228 CHC patients treated with pegylated interferon (PEG-IFN) and ribavirin (RBV), 165 (13%) had a relapse. Among these, 62 patients were retreated with PEG-IFN-α2a or -α2b and RBV. Clinical, biological, virological and histological data were collected. Initial doses and treatment modifications were recorded. The efficacy of retreatment and predictive factors for SVR were analyzed.
RESULTS: An SVR was achieved in 42% of patients. SVR was higher in young (< 50 years) (61%) than old patients (27%) (P = 0.007), and in genotype 2 or 3 (57%) than in genotype 1 or 4 (28%) patients (P = 0.023). Prolonging therapy for at least 24 wk more than the previous course was associated with higher SVR rates (53% vs 28%, P = 0.04). Also, a better SVR rate was observed with RBV dose/body weight > 15.2 mg/kg per day (70% vs 35%, P = 0.04). In logistic regression, predictors of a response were age (P = 0.018), genotype (P = 0.048) and initial RBV dose/body weight (P = 0.022). None of the patients without a complete early virological response achieved an SVR (negative predictive value = 100%).
CONCLUSION: Retreatment with PEG-IFN/RBV is eff-ective in genotype 2 or 3 relapsers, especially in young patients. A high dose of RBV seems to be important for the retreatment response.
PMCID: PMC3380324  PMID: 22736920
Chronic hepatitis C; Relapse; Retreatment; Ribavirin; Pegylated interferon
6.  Ex vivo induction of IFN-λ3 by a TLR7 agonist determines response to Peg-IFN/Ribavirin therapy in chronic hepatitis C patients 
Journal of Gastroenterology  2013;49(1):126-137.
Genetic variation around interleukin-28B (IL28B), encoding IFN-λ3, predict non-responders to pegylated interferon-α/ribavirin (Peg-IFN/RBV) therapy in chronic hepatitis C (CHC). However, it remains unclear the expression and the role of IL28B itself. The aim of this study is to develop easy and useful methods for the prediction of treatment outcomes.
The mRNA and protein levels of IFN-λ3 induced by ex vivo stimulation of peripheral blood mononuclear cells (PBMC) or magnetically selected dendritic cells (DCs) with toll-like receptor agonists (TLR3; poly I:C, TLR7; R-837) were measured by the quantitative real-time polymerase chain reaction and our newly developed chemiluminescence enzyme immunoassays, respectively, and compared with the clinical data.
We found that BDCA-4+ plasmacytoid and BDCA-3+ myeloid DCs were the main producers of IFN-λs when stimulated with R-837 and poly I:C, respectively. Detectable levels of IFN-λs were inducible even in a small amount of PBMC, and IFN-λ3 was more robustly up-regulated by R-837 in PBMC of CHC patients with favorable genotype for the response to Peg-IFN/RBV (TT in rs8099917) than those with TG/GG. Importantly, the protein levels of IFN-λ3 induced by R-837 clearly differentiated the response to Peg-IFN/RBV treatment (p = 1.0 × 10−10), including cases that IL28B genotyping failed to predict the treatment response. The measurement of IFN-λ3 protein more accurately predicted treatment efficacies (95.7 %) than that of IL28B genotyping (65.2 %).
Genetic variations around IL28B basically affect IFN-λ3 production, but different amounts of IFN-λ3 protein determines the outcomes of Peg-IFN/RBV treatment. This study, for the first time, presents compelling evidence that IL28B confer a functional phenotype.
Electronic supplementary material
The online version of this article (doi:10.1007/s00535-013-0814-1) contains supplementary material, which is available to authorized users.
PMCID: PMC3895210  PMID: 23591768
Chronic hepatitis C; IL28B; IFN-λ3; Peg-IFN/RBV
7.  Hematological Adverse events and Sustained Viral Response in Children Undergoing Therapy for Chronic Hepatitis C Infection 
Hepatitis Monthly  2011;11(12):968-974.
Treatment of hepatitis C virus (HCV) infection with interferon (IFN) and ribavirin (RBV) is associated with adverse events, which may affect the patient's adherence to the treatment regimen and the treatment efficacy.
The aim of this study was to assess the sustained viral response (SVR) and interdependence between the haematological characteristics (leukocyte count, platelet count, and haemoglobin levels) in patients with chronic hepatitis C (CHC) infection during treatment with IFN and RBV.
Patients and Methods
We conducted a retrospective cohort study of 170 children with CHC infection who completed treatment with IFN-α and RBV. The children were divided into 2 groups: the first group (group I, n = 119) underwent a 48-week course of treatment with recombinant IFN α-2b (Intron A) at a dosage of 3 MU 3 times a week subcutaneously and RBV at a dosage of 15 mg/kg per day orally, and the second group (group II, n = 51) was administered pegylated IFN (peg-IFN)-α-2b (PegIntron) at a dosage of 1.5 μg/kg per week subcutaneously and RBV at a dosage of 15 mg/kg per day orally for 48 weeks. The dose of IFN was not adjusted but that of ribavirin was in 2 children from group II. Hematological growth factors and erythropoietin were not used. SVR was defined as undetectable serum HCV RNA 24 weeks after the end of treatment (study week 72). Serum HCV RNA was determined by performing polymerase chain reaction, and the HCV genotypes and hematological parameters were evaluated. Serum HCV RNA levels were analysed by descriptive statistics. Means and standard deviations were calculated for values collected at the baseline, on the 12th and 48th weeks during treatment, and after 24 weeks of untreated follow-up (study week 72).
Eighty-six (50%) of the 170 patients who underwent treatment achieved SVR: 62 (51%) out of 119 children from group I and 24 (47%) out of 51 from group II. The mean serum hemoglobin levels and leukocyte and platelet counts at week 12 were significantly lower than the baseline values in both responders and non-responders from both the groups (P < 0.05). In the responders in group I, the mean levels of serum hemoglobin after 24 weeks of treatment and at the end of therapy were significantly lower than the mean levels at baseline. In the group treated with peg-IFN-α-2b and RBV (group II), the mean serum hemoglobin levels at week 12 was lower in the responders than in the non-responders (P < 0.05). The decrease in the hemoglobin levels was associated with viral response. In both the responders and non-responders from both the groups, leukocyte counts decreased during treatment, and after 12 weeks, they were more significantly lower than the baseline value. The decrease was more marked in children treated with peg-IFN-α-2b + RBV (P < 0.05). After 12 weeks of treatment, the platelet count was low in children from group II who had achieved SVR.
A mild decrease in hemoglobin levels and leukocyte and platelet counts during treatment with IFN and RBV in children with CHC infection may be factors responsible for SVR induction.
PMCID: PMC3282029  PMID: 22368680
Hepatitis C; Child; Therapeutics
8.  Hepatitis C Viral Kinetics in the Era of Direct Acting Antiviral Agents and IL28B 
Current hepatitis reports  2011;10(3):214-227.
In the last decade hepatitis C virus (HCV) kinetics has become an important clinical tool for the optimization of therapy with (pegylated)-interferon-α (IFN) and ribavirin (RBV). Mathematical models have generated important insights into HCV pathogenesis, HCV- host dynamics, and IFN and RBV’s modes of action. Clinical trials with direct acting agents (DAAs) against various steps of the HCV life cycle have revealed new viral kinetic patterns that have not been observed with IFN±RBV. Very recently, studies have showed that single nucleotide polymorphisms (SNPs) in the IL28B gene region were associated with race/ethnicity and with response to IFN±RBV. Here we review our current knowledge of HCV kinetics and related mathematical models during IFN±RBV and/or DAA based therapies, HCV pathogenesis, and the role of IL28B polymorphism on early HCV kinetics. Better understanding of the mode of actions of drug(s) and viral kinetics may help to develop, in the near future, new individualized therapeutic regimens that include DAAs in combination with IFN+RBV.
PMCID: PMC3237049  PMID: 22180724
9.  Current progress in the treatment of chronic hepatitis C 
Over the last decade, the standard of care for the treatment of chronic hepatitis C has been the combination of pegylated-interferon-alfa (PEG-IFN) and ribavirin (RBV) which results in sustained virological response (SVR) rates of 75%-85% in patients with genotypes 2 or 3 but only of 40%-50% in patients with genotype 1. Currently, there are rapid and continuous developments of numerous new agents against hepatitis C virus (HCV), which are the focus of this review. Boceprevir and telaprevir, two first-generation NS3/4A HCV protease inhibitors, have been recently licensed in several countries around the world to be used in combination with PEG-IFN and RBV for the treatment of genotype 1 patients. Boceprevir or telaprevir based triple regimens, compared with the PEG-IFN/RBV combination, improve the SVR rates by 25%-31% in treatment-naïve genotype 1 patients, by 40%-64% in prior relapsers, by 33%-45% in prior partial responders and by 24%-28% in prior null responders. At the same time, the application of response-guided treatment algorithms according to the on-treatment virological response results in shortening of the total therapy duration to only 24 wk in 45%-55% of treatment-naïve patients. There are, however, several challenges with the use of the new triple combinations in genotype 1 patients, such as the need for immediate results of HCV RNA testing using sensitive quantitative assays, new and more frequent adverse events (anemia and dysgeusia for boceprevir; pruritus, rash and anemia for telaprevir), new drug interactions and increasing difficulties in compliance. Moreover, the SVR rates are still poor in very difficult to treat subgroups of genotype 1 patients, such as null responders with cirrhosis, while there is no benefit for patients who cannot tolerate PEG-IFN/RBV or who are infected with non-1 HCV genotype. Many newer anti-HCV agents of different classes and numerous combinations are currently under evaluation with encouraging results. Preliminary data suggest that the treatment of chronic HCV patients with well tolerated combinations of oral agents without PEG-IFN is feasible and may lead to a universal HCV cure over the next 5-10 years.
PMCID: PMC3496882  PMID: 23155334
Chronic hepatitis C; Pegylated interferon; Ribavirin; Protease inhibitors; Nucleos(t)ide analogue inhibitors; Non-nucleos(t)ide analogue inhibitors; Hepatitis C virus polymerase; NS5A inhibitors; Cyclophilin inhibitors
10.  The effectiveness of retreatment with peginterferon alfa and ribavirin in patients with chronic viral hepatitis C genotype 2 and 3: a prospective cohort study in Brazil 
BMC Infectious Diseases  2012;12:377.
More than 50% of patients infected with chronic hepatitis C virus (HCV) do not respond to treatment with conventional interferon (IFN) combined with ribavirin (RBV). The aim of our study was to evaluate the effectiveness of retreatment with peginterferon alfa-2a or 2b (PEG-IFN 2a or 2b) concomitantly with RBV in patients with HCV genotype 2 and 3, which were non-responders or relapsers to initial treatment with IFN / RBV and to identify possible predictors of sustained virological response (SVR).
From September 2003 to March 2009 a cohort of 216 patients who had previously failed therapy with a regimen of standard interferon and ribavirin, were followed in a specialized service implemented in the Brazilian Unified Health System, Rio Grande do Sul. All patients were retreated with PEG-IFN 2a or 2b per week, associated with RBV, through oral route, with doses determined according to weight (1,000 mg if weight ≤ 75 Kg and 1,250 mg if ≥ 75 Kg) per day for 48 weeks. The HCV-RNA was tested by Polymerase Chain Reaction (PCR). Virological Response (VR) within 48 weeks and SVR in the 72 weeks was considered for evaluation of treatment efficacy. Analyses were performed in patients who received at least one dose of PEG-IFN.
The SVR rate for non-responders to previous treatment was 34.4% and for relapsers was 50% (p = 0.031). As predictive factors that contribute to improve SVR, were identified the age (p = 0.005), to be relapsers to previous treatment (p = 0.023) and present liver biopsy examination Metavir F0-F2 (p = 0.004). In assessing the safety profile, 51 patients (23.6%) discontinued treatment prematurely.
This alternative retreatment for patients who have failed prior therapies for anti-HCV, has demonstrated promising SVR rate, provided that it includes a careful selection of patients with predictors of response and adverse events monitored.
PMCID: PMC3548710  PMID: 23270376
Hepatitis C; Retreatment; Peginterferon alpha; Ribavirin
11.  386 Hypersensitivity Reactions to Interferon Based Treatment for Hepatitis C: A Single Center 20-Year Experience 
BA Interferon (IFN)-based therapy for chronic hepatitis C (CHC) is associated with adverse hypersensitivity reactions (HRs). However, data on HRs to IFN in every-day clinical practice are lacking. We conducted a retrospective study to identify the incidence, management and outcome of such reactions.
A review of the electronic files of all CHC patients followed in our tertiary referral center from January 1990 to November 2010 was conducted to identify patients submitted to IFN-based treatment and HRs to such treatment.
During the study period, 832 CHC patients were identified, 545 (65.5%) of whom received IFN-based treatment. Overall, 221 (40.5%) patients received at least one treatment cycle with IFN-a ± ribavirin (RBV), 170 (31.2%) patients received at least one treatment cycle with pegylated (PEG)-IFN a2a + RBV and 189 (34.7%) patients received at least one treatment cycle with PEG-IFN a2b + RBV. Fifty-five treatment cycles were complicated by HRs in 54 patients (female 20, median age 39 years, range 22–65 years). Presenting symptoms of HRs were: skin rash in 46 patients (pruritic in 20), generalized pruritus in 7 patients and aphthous mucosal ulcers in 2 patients. HRs occurred in 9 patients treated with IFN-a (4.1%), 23 patients treated with PEG-IFN a2a (13.5%) and 23 patients treated with PEG-IFN a2b (12.1%) (P = 0.002). Management of HRs included no intervention in 18 (32.7%) cases, topical treatment in 10 (18.2%) cases, antihistamine administration in 15 (27.3%) cases, temporary cessation of treatment or dose reduction in 3 (5.5%) cases, switch from PEG-IFN to IFN-a in 4 (7.3%) cases and immediate termination of treatment in 5 (9.1%) cases. The outcome was complete remission of the HR in 33 (60%) cases, remission sufficient to allow continuation of treatment in 13 (23.6%) cases and treatment termination in 8 (14.5%) cases, while one (1.8%) patient was lost to follow-up after the HR. Overall, 2 (0.9%) patients discontinued IFN-a, 3 (1.8%) PEG-IFN a2a and 3 (1.6%) PEG-IFN a2b due to HRs (P = 0.737).
Hypersensitivity reactions to IFN-based and especially to PEG-IFN based treatment regimens are occasionally encountered in CHC patients and may rarely lead to treatment termination.
PMCID: PMC3513057
12.  Prediction of Effect of Pegylated Interferon Alpha-2b plus Ribavirin Combination Therapy in Patients with Chronic Hepatitis C Infection 
PLoS ONE  2011;6(12):e27223.
Treatment with pegylated interferon alpha-2b (PEGIFN) plus ribavirin (RBV) is standard therapy for patients with chronic hepatitis C. Although the effectiveness, patients with high titres of group Ib hepatitis C virus (HCV) respond poorly compared to other genotypes. At present, we cannot predict the effect in an individual. Previous studies have used traditional statistical analysis by assuming a linear relationship between clinical features, but most phenomena in the clinical situation are not linearly related. The aim of this study is to predict the effect of PEG IFN plus RBV therapy on an individual patient level using an artificial neural network system (ANN). 156 patients with HCV group 1b from multiple centres were treated with PEGIFN (1.5 µg/kg) plus RBV (400–1000 mg) for 48 weeks. Data on the patients' demographics, laboratory tests, PEGIFN, and RBV doses, early viral responses (EVR), and sustained viral responses were collected. Clinical data were randomly divided into training data set and validation data set and analyzed using multiple logistic regression analysis (MLRs) and ANN to predict individual outcomes. The sensitivities of predictive expression were 0.45 for the MLRs models and 0.82 for the ANNs and specificities were 0.55 for the MLR and 0.88 for the ANN. Non-linear relation analysis showed that EVR, serum creatinine, initial dose of Ribavirin, gender and age were important predictive factors, suggesting non-linearly related to outcome. In conclusion, ANN was more accurate than MLRs in predicting the outcome of PEGIFN plus RBV therapy in patients with group 1b HCV.
PMCID: PMC3229481  PMID: 22164207
13.  Intelligent Sensor Positioning and Orientation Through Constructive Neural Network-Embedded INS/GPS Integration Algorithms 
Sensors (Basel, Switzerland)  2010;10(10):9252-9285.
Mobile mapping systems have been widely applied for acquiring spatial information in applications such as spatial information systems and 3D city models. Nowadays the most common technologies used for positioning and orientation of a mobile mapping system include a Global Positioning System (GPS) as the major positioning sensor and an Inertial Navigation System (INS) as the major orientation sensor. In the classical approach, the limitations of the Kalman Filter (KF) method and the overall price of multi-sensor systems have limited the popularization of most land-based mobile mapping applications. Although intelligent sensor positioning and orientation schemes consisting of Multi-layer Feed-forward Neural Networks (MFNNs), one of the most famous Artificial Neural Networks (ANNs), and KF/smoothers, have been proposed in order to enhance the performance of low cost Micro Electro Mechanical System (MEMS) INS/GPS integrated systems, the automation of the MFNN applied has not proven as easy as initially expected. Therefore, this study not only addresses the problems of insufficient automation in the conventional methodology that has been applied in MFNN-KF/smoother algorithms for INS/GPS integrated systems proposed in previous studies, but also exploits and analyzes the idea of developing alternative intelligent sensor positioning and orientation schemes that integrate various sensors in more automatic ways. The proposed schemes are implemented using one of the most famous constructive neural networks—the Cascade Correlation Neural Network (CCNNs)—to overcome the limitations of conventional techniques based on KF/smoother algorithms as well as previously developed MFNN-smoother schemes. The CCNNs applied also have the advantage of a more flexible topology compared to MFNNs. Based on the experimental data utilized the preliminary results presented in this article illustrate the effectiveness of the proposed schemes compared to smoother algorithms as well as the MFNN-smoother schemes.
PMCID: PMC3230954  PMID: 22163407
GPS/INS; sensor integration; mobile mapping systems; constructive neural networks
14.  Treatment of Naïve Patients with Chronic Hepatitis C Genotypes 2 and 3 with Pegylated Interferon Alpha and Ribavirin in a Real World Setting: Relevance for the New Era of DAA 
PLoS ONE  2014;9(10):e108751.
Evidence based clinical guidelines are implemented to treat patients efficiently that include efficacy, tolerability but also health economic considerations. This is of particular relevance to the new direct acting antiviral agents that have revolutionized treatment of chronic hepatitis C. For hepatitis C genotypes 2/3 interferon free treatment is already available with sofosbuvir plus ribavirin. However, treatment with sofosbuvir-based regimens is 10–20 times more expensive compared to pegylated interferon alfa and ribavirin (PegIFN/RBV). It has to be discussed if PegIFN/RBV is still an option for easy to treat patients. We assessed the treatment of patients with chronic hepatitis C genotypes 2/3 with PegIFN/RBV in a real world setting according to the latest German guidelines. Overall, 1006 patients were recruited into a prospective patient registry with 959 having started treatment. The intention-to-treat analysis showed poor SVR (GT2 61%, GT3 47%) while patients with adherence had excellent SVR in the per protocol analysis (GT2 96%, GT3 90%). According to guidelines, 283 patients were candidates for shorter treatment duration, namely a treatment of 16 weeks (baseline HCV-RNA <800.000 IU/mL, no cirrhosis and RVR). However, 65% of these easy to treat patients have been treated longer than recommended that resulted in higher costs but not higher SVR rates. In conclusion, treatment with PegIFN/RBV in a real world setting can be highly effective yet similar effective than PegIFN± sofosbuvir/RBV in well-selected naïve G2/3 patients. Full adherence to guidelines could be further improved, because it would be important in the new era with DAA, especially to safe resources.
PMCID: PMC4193764  PMID: 25302676
15.  Identification of Treatment Efficacy–Related Host Factors in Chronic Hepatitis C by ProteinChip Serum Analysis 
Molecular Medicine  2010;17(1-2):70-78.
Recent development of proteomic array technology, including protein profiling coupling ProteinChip array with surface-enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI-TOF/MS), provides a potentially powerful tool for discovery of new biomarkers by comparison of its profiles according to patient phenotypes. We used this approach to identify the host factors associated with treatment response in patients with chronic hepatitis C (CHC) receiving a 48-wk course of pegylated interferon (PEG-IFN) alpha 2b plus ribavirin (RBV). Protein profiles of pretreatment serum samples from 32 patients with genotype 1b and high viral load were conducted by SELDI-TOF/MS by using the three different ProteinChip arrays (CM10, Q10, IMAC30). Proteins showed significantly different peak intensities between sustained virological responders (SVRs), and non-SVRs were identified by chromatography, SDS-PAGE, TOF/MS and tandem mass spectrometry (MS/MS) assay. Eleven peak intensities were significantly different between SVRs and non-SVRs. The three SVR-increased peaks could be identified as two apolipoprotein (Apo) fragments and albumin and, among the eight non–SVR-increased proteins, four peaks identified as two iron-related and two fibrogenesis-related protein fragments, respectively. Multivariate analysis showed that the serum ferritin and three peak intensity values (Apo A1, hemopexin and transferrin) were independent variables associated with SVRs, and the area under the receiver operating characteristic (ROC) curves for SVR prediction by using the Apo A1/hemopexin and hemopexin/transferrin were 0.964 and 0.936. In conclusion, pretreatment serum protein profiling by SELDI-TOF/MS is variable for identification of response-related host factors, which are useful for treatment efficacy prediction in CHC receiving PEG-IFN plus RBV. Our data also may help us understand the mechanism for treatment resistance and development of more effective antiviral therapy targeted toward the modulation of lipogenesis or iron homeostasis in CHC patients.
PMCID: PMC3022982  PMID: 20927485
16.  Complexity and Catalytic Efficiency of Hepatitis C Virus (HCV) NS3 and NS4A Protease Quasispecies Influence Responsiveness to Treatment with Pegylated Interferon plus Ribavirin in HCV/HIV-Coinfected Patients▿† 
Journal of Virology  2011;85(12):5961-5969.
The role of the hepatitis C virus (HCV) NS3/4A protease in ablating the signaling pathway involved in the production of alpha/beta interferon (IFN-α/β) suggests a relationship between NS3/4A proteolytic activity and a patient's response to IFN-based therapy. To identify viral factors associated with the HCV treatment response, we analyzed the pretreatment NS3/4A protease gene quasispecies composition of 56 HCV genotype 1–HIV-1-coinfected patients treated in our clinic with pegylated IFN (pegIFN) plus ribavirin (RBV). The catalytic efficiency of the dominant (i.e., the most abundant) quasispecies was also assayed for Cardif cleavage and correlated with treatment outcome. A total of 1,745 clones were isolated and sequenced. Significantly less nucleotide quasispecies heterogeneity and lower Shannon entropy values were detected within the responder group (P < 0.05). A correlation was also found between the efficiency of NS3/4A protease Cardif cleavage and therapy outcome. Proteases from sustained responder patients were more efficient at processing Cardif (mean ± standard error of the mean [SEM], 0.8960 ± 0.05568; n = 19) than proteases from nonresponders (mean ± SEM, 0.7269 ± 0.05306; n = 37; P < 0.05). Finally, the amino acid p distance (the proportion [p] of nucleotide sites at which two sequences being compared are different) was significantly shorter in patients with an interleukin-28B (IL-28B) risk allele (P < 0.01), suggesting that IL-28B risk allele carriers exert a lower positive selection pressure on the NS3/4A protease. NS3/4A protease efficiency in cleaving Cardif may be associated with the pegIFN-RBV treatment response, as shown in our cohort of HIV-HCV-coinfected patients. Greater NS3/4A nucleotide heterogeneity and higher Shannon entropy values in nonresponders suggest that less HCV quasispecies complexity may favor a better response to pegIFN-RBV.
PMCID: PMC3126303  PMID: 21471227
17.  The Effect of Peginterferon Alpha-2a vs. Peginterferon Alpha-2b in Treatment of Naive Chronic HCV Genotype-4 Patients: A Single Centre Egyptian Study 
Hepatitis Monthly  2013;13(5):e10069.
Egypt has one of the highest (16-8%) prevalence rates of HCV infection in the world. Approximately 90% of Egyptian HCV isolates belong to a single subtype (4a), which responds less successfully to interferon therapy than other subtypes. Studies comparing the efficacy and safety of PEGIFN alfa-2a and PEGIFN alfa-2b in treatment-naive HCV-infected patients have shown conflicting results.
Assessing the effects of Peginterferon alpha-2a versus Peginterferon alpha-2b on the sustained virological response in naive chronic HCV genotype-4 Egyptian patients.
Patients and Methods
This retrospective study cohort consists of 3718 chronic HCV patients admitted to a large, Egyptian medical center. 1985 patients had been treated with PEG-IFN alfa-2a plus RBV and 1733 patients with PEG-IFN alfa-2b plus RBV between years 2007-2011. Efficacy outcomes were sustained virologic response (SVR) and treatment discontinuation rates due to serious adverse effects.
The ETR & SVR in patients treated with PEGIFN alfa-2a was 64.1% and 59.6% as compared to treatment with PEGIFN alfa-2b where these parameters were 58.2% and 53.9% respectively (P < 0.05). Treatment discontinuation rates, were similar in the two types of PEGIFN [0.66 (0.37-1.16); P = 0.15]. Significant dose reduction was evident with peginterferon alfa-2b (35.3%) than peginterferon alpha-2a (27.3 %) (P < 0.01). Patients with lower base line AFP and ALT were most likely to achieve SVR using INF alpha 2-a.
Peginterferon alpha-2a has a higher efficacy regarding ETR and SVR as compared to Peginterferon alfa-2b in treatment of naive chronic HCV genotype-4 patients.
PMCID: PMC3732660  PMID: 23922556
Chronic Hepatitis C; Peginterferon-Alpha- 2a; Peginterferon-Alpha- 2b
18.  Peginterferon Alfa-2a Is Associated with Elevations in Alanine Aminotransferase at the End of Treatment in Chronic Hepatitis C Patients with Sustained Virologic Response 
PLoS ONE  2014;9(6):e100207.
The purpose of this study was to investigate the incidence and demographic/clinical factors of alanine aminotransferase (ALT) abnormalities at the end of treatment (EOT) in chronic hepatitis C (CHC) patients with sustained virologic response (SVR).
Methods and Findings
Seven hundred naïve CHC patients who underwent combination treatment between January 2003 and December 2010 were included in the study. The patients with SVR and serum ALT>upper limit of normal (ULN) at the EOT were further analyzed. The effects of clinical characteristics, treatment regimen, and virologic variables were evaluated by logistic regression. Of the 700 included patients, 488 (69.7%) achieved an SVR after treatment, and 235 (33.6%) had serum ALT levels>ULN at the EOT. Of those 488 patients, 137 (28.1%) had abnormal ALT values at the EOT. A multivariate analysis showed that the occurrence of ALT abnormalities at the EOT was significantly associated with pegylated interferon (PEG-IFN) alfa-2a (odds ratio [OR], 2.24; 95% confidence interval [CI], 1.45–3.45; P<0.001), baseline fatty liver (OR, 1.76; 95% CI, 1.16–2.76; P = 0.007), and baseline liver cirrhosis (OR, 2.35; 95% CI, 1.35–4.09; P = 0.002).
Use of PEG-IFN-alfa-2a, fatty liver, and cirrhosis are important factors associated with EOT-ALT abnormality in CHC patients receiving combination therapy that achieve an SVR. PEG-IFN-alfa-2a-related EOT-ALT elevation will become normal at the end of follow-up, but fatty liver and cirrhosis-related ALT elevation will not be resolved.
PMCID: PMC4061072  PMID: 24937007
19.  Efficacy and Tolerability of Combination Therapy with Interferon-Alfa Plus Ribavirin in Patients with Chronic Hepatitis C Virus Infection: A Single-Center Study in Relapsers and Nonresponders to Previous Treatment with High-Dose Interferon-Alfa Monotherapy 
Background: In chronic hepatitis C virus (HCV) infection, interferon (IFN) monotherapy usually is carried out at doses of 3 to 6 million units (MU) 3 times per week, but treatment efficacy is low.
Objective: The aim of our study was to assess the efficacy and tolerability of IFN-alfa2b in combination with ribavirin in relapsers and nonresponders to high-dose IFN treatment (5 to 6 MU 3 times per week). We measured the biochemical and virologic responses to treatment and the risk for relapse during the 24 weeks following the end of treatment.
Methods: Patients with chronic HCV infection (relapsers and nonresponders to a previous treatment with high-dose IFN) received IFN-alfa2b, 3 MU 3 times per week, and ribavirin, 1000 or 1200 mg/d for 24 or 48 weeks. The patients were then followed up for an additional 24 weeks. Sustained response was defined as normal serum alanine aminotransferase (ALT) level and undetectable HCV RNA 24 weeks after treatment was stopped.
Results: Forty-three patients (32 men, 11 women; mean [SD] age, 45 [2] years; 10 relapsers, 33 nonresponders) were included in the study. Four patients were withdrawn from the study at week 4 of treatment because of treatment-related adverse events, and 1 dropped out. At the end of the treatment period, normalization of serum ALT levels and undetectable HCV RNA levels were seen in 58.1% and 30.2% of patients, respectively. No significant difference in virologic response at the end of treatment was found between nonresponders (10/33 [30.3%]) to previous IFN therapy and relapsers (3/10 [30.0%]). At the end of follow-up, 3 (7.0%) treated patients had sustained response (2 nonresponders to the first IFN course and 1 relapser). All of the patients with sustained response were treated for 24 weeks.
Conclusion: Based on the results of our study, combination therapy with IFN-alfa and ribavirin may be of value in a limited number of patients with chronic HCV infection who do not respond to, or relapse after, a first course of treatment with high-dose IFN monotherapy.
PMCID: PMC4053042  PMID: 24944362
chronic hepatitis C virus; high-dose interferon; ribavirin; combination therapy
20.  Efficacy and safety of telaprevir, a new protease inhibitor, for difficult-to-treat patients with genotype 1 chronic hepatitis C 
Journal of Viral Hepatitis  2012;19(2):e134-e142.
The aims of this phase III study were to assess the efficacy and safety of telaprevir in combination with peginterferon alfa-2b (PEG-IFN) and ribavirin (RBV) for difficult-to-treat patients who had not achieved sustained virological response (SVR) to prior regimens in Japan. The subjects were 109 relapsers (median age of 57.0 years) and 32 nonresponders (median age of 57.5 years) with hepatitis C virus genotype 1. Patients received telaprevir (750 mg every 8 h) for 12 weeks and PEG-IFN/RBV for 24 weeks. The SVR rates for relapsers and nonresponders were 88.1% (96/109) and 34.4% (11/32), respectively. Specified dose modifications of RBV that differed from that for the standard of care were introduced to alleviate anaemia. RBV dose reductions were used for 139 of the 141 patients. The SVR rates for relapsers did not depend on RBV dose reduction for 20–100% of the planned dose (SVR rates 87.5–100%, P < 0.05). Skin disorders were observed in 82.3% (116/141). Most of the skin disorders were controllable by anti-histamine and/or steroid ointments. The ratios of discontinuation of telaprevir only or of all the study drugs because of adverse events were 21.3% (30/141) and 16.3% (23/141), respectively. A frequent adverse event leading to discontinuation was anaemia. Telaprevir in combination with PEG-IFN/RBV led to a high SVR rate for relapsers and may offer a potential new therapy for nonresponders even with a shorter treatment period.
PMCID: PMC3489056  PMID: 22239511
direct-acting antiviral; peginterferon; ribavirin; sustained virological response; treatment failure
21.  Interferon and Ribavirin Combination Treatment Synergistically Inhibit HCV Internal Ribosome Entry Site Mediated Translation at the Level of Polyribosome Formation 
PLoS ONE  2013;8(8):e72791.
Although chronic hepatitis C virus (HCV) infection has been treated with the combination of interferon alpha (IFN-α) and ribavirin (RBV) for over a decade, the mechanism of antiviral synergy is not well understood. We aimed to determine the synergistic antiviral mechanisms of IFN-α and RBV combination treatment using HCV cell culture.
The antiviral efficacy of IFN-α, RBV alone and in combination was quantitatively measured using HCV infected and replicon cell culture. Direct antiviral activity of these two drugs at the level of HCV internal ribosome entry site (IRES) mediated translation in Huh-7 cell culture was investigated. The synergistic antiviral effect of IFN-α and RBV combination treatment was verified using both the CalcuSyn Software and MacSynergy Software.
RBV combination with IFN-α efficiently inhibits HCV replication cell culture. Our results demonstrate that IFN-α, interferon lambda (IFN-λ) and RBV each inhibit the expression of HCV IRES-GFP and that they have a minimal effect on the expression of GFP in which the translation is not IRES dependent. The combination treatments of RBV along with IFN-α or IFN-λ were highly synergistic with combination indexes <1. We show that IFN-α treatment induce levels of PKR and eIF2α phosphorylation that prevented ribosome loading of the HCV IRES-GFP mRNA. Silencing of PKR expression in Huh-7 cells prevented the inhibitory effect of IFN-α on HCV IRES-GFP expression. RBV also blocked polyribosome loading of HCV-IRES mRNA through the inhibition of cellular IMPDH activity, and induced PKR and eIF2α phosphorylation. Knockdown of PKR or IMPDH prevented RBV induced HCV IRES-GFP translation.
We demonstrated both IFN-α and RBV inhibit HCV IRES through prevention of polyribosome formation. The combination of IFN-α and RBV treatment synergistically inhibits HCV IRES translation via using two different mechanisms involving PKR activation and depletion of intracellular guanosine pool through inhibition of IMPDH.
PMCID: PMC3751885  PMID: 24009705
22.  A reduced dose of ribavirin does not influence the virologic response during pegylated interferon alpha-2b and ribavirin combination therapy in patients with genotype 1 chronic hepatitis C 
Clinical and molecular hepatology  2012;18(3):272-278.
When combined with pegylated interferon alpha-2b (Peg-IFN α-2b) for the treatment of genotype 1 chronic hepatitis C (CHC) in Korea, the current guideline for the initial ribavirin (RBV) dose is based on body weight. However, since the mean body weight is lower for Korean patients than for patients in Western countries, current guidelines might result in Korean patients being overdosed with RBV.
We retrospectively reviewed the medical records of patients with genotype 1 CHC who were treated with Peg-IFN α-2b and RBV combination therapy. We divided the patients into groups A (≥15 mg/kg/day, n=23) and B (<15 mg/kg/day, n=26), given that the standard dose is 15 mg/kg/day. The clinical course in terms of the virologic response, adverse events, and dose modification rate was compared between the two groups after therapy completion.
The early response rates (92.0% vs. 83.3%, P=0.634) and sustained virologic response rates (82.6% vs. 73.1%, P=0.506) did not differ significantly between the two groups. During the treatment period, the RBV dose reduction rate was significantly higher in group A than in group B (60.9% vs. 23.1%, P=0.01).
RBV dose reduction is performed frequently when patients are treated according to the current Korean guidelines. Given that lowering the RBV dose did not appear to decrease the virologic response during therapy, reducing RBV doses below the current Korean guideline may be effective for treatment, especially in low-weight patients.
PMCID: PMC3467430  PMID: 23091807
Ribavirin; Pegylated interferon alpha-2b; Chronic hepatitis C; Sustained virologic response; Koreans
23.  Expert opinion on the treatment of patients with chronic hepatitis C 
Journal of Viral Hepatitis  2009;16(2):75-90.
The current preferred treatment for patients with hepatitis C virus (HCV) is combination therapy consisting of pegylated interferon alfa and ribavirin (RBV) for 24–48 weeks. Although this approach appears to be highly effective for patients with HCV genotypes 2 or 3, who have a sustained virological response (SVR) of approximately 80%, the treatment algorithm is less effective for patients with HCV genotype 1, as these patients have SVR rates of just 40–50%. In order to improve treatment outcomes, this article explores potential approaches for the optimization of treatment for patients with HCV genotype 1: considering shorter treatment periods for patients with a rapid virological response (RVR), increasing treatment periods for slow responders, and increasing RBV dose are all suggestions. Results from clinical trials suggest that approximately 20% of the HCV genotype 1-infected population are slow responders, and around 15% of all HCV genotype-1 infected patients could benefit from a shorter treatment duration without compromising the SVR rate. Interest has also focused on whether treatment duration could be individualized in some patients with genotype 2 and 3 infection. Here all the findings from recent studies are translated into practical advice, to help practitioners make evidence-based treatment decisions in everyday clinical practice. Although there are areas where currently available data do not provide conclusive evidence to suggest amending treatment approaches, there is clearly potential for individualized treatment in all aspects of hepatitis treatment in the future.
PMCID: PMC2759987  PMID: 18761607
hepatitis C; pegylated interferon alfa; ribavirin; treatment; virological response
24.  Comparative Effectiveness of Telaprevir-Based Triple Therapy in Patients with Chronic Hepatitis C 
Mayo Clinic proceedings  2014;89(5):595-601.
To examine the effectiveness and tolerability of triple therapy with pegylated interferon (p-IFN), ribavirin (RBV) and telaprevir (TPV) in chronic hepatitis C (CHC) patients treated in an academic practice setting, among a more clinically diverse population than was treated in phase 3 trials.
A prospective database of all viral hepatitis patients undergoing antiviral therapy from January 1, 2006 – July 1, 2012 was queried to identify treatment naïve and experienced CHC patients treated with dual and triple therapy. On-treatment response categories included: rapid virologic response (RVR), extended rapid virologic response (eRVR), early virologic response (EVR), and sustained virologic response (SVR). These patients were compared to matched controls, namely patients that underwent dual therapy with p-IFN and RBV. Matching was performed for age, cirrhosis status and history of previous treatment.
There were 55 patients treated with triple therapy who met the eligibility criteria, consisting of treatment-naïve (n=35) and–experienced (n=20, relapse=9, non-response=9, and previous early-terminators n=2). RVR was achieved in 41%, eRVR in 41% and EVR in 75%. SVR was observed in 51% of treatment naïve patients, 67% of non-responders, and 56% of those with prior relapse. Corresponding results after dual therapy were 37%, 11% and 27%, respectively. The mean drop in hemoglobin at weeks 4, 8 and 24 of triple therapy were 2.8 mg/dl, 3.8 mg/dl and 3.2 mg/dl, compared to 2.4 mg/dl, 2.6 mg/dl and 2.4 mg/dl with dual therapy.
Telaprevir triple therapy in clinical practice is more effective than p-IFN/RBV dual therapy despite the significant degree of anemia that complicated therapy requiring RBV dose reduction and erythropoietin support.
PMCID: PMC4160303  PMID: 24661475
25.  Short Communication: Interferon/Ribavirin Treatment for HCV Is Associated with the Development of Hypophosphatemia in HIV/Hepatitis C Virus-Coinfected Patients 
AIDS Research and Human Retroviruses  2013;29(9):1190-1194.
One-third of all HIV-infected individuals in the United States are estimated to be coinfected with the hepatitis C virus (HCV). Treatment of chronic hepatitis C in patients coinfected with HIV is a complex problem associated with toxicities and drug interactions between HIV antiretrovirals and interferon and ribavirin. In recent HCV treatment studies, we observed a previously unreported development of hypophosphatemia in HIV/HCV-coinfected patients treated with interferon/ribavirin (IFN/RBV). To further investigate this observation, we retrospectively reviewed 61 HIV/HCV-coinfected patients on antiretrovirals (ARVs) during treatment with IFN/RBV as well as 154 HIV-infected patients treated with ARVs alone. We found that HIV/HCV-coinfected patients on IFN/RBV therapy were more likely to develop frequent (57% vs. 13%, IFN/RBV-treated patients vs. no IFN/RBV; χ2=0.001) and higher-grade hypophosphatemia (67.0% Grade 2, 33.3% Grade 3 vs. 94.7% Grade 2, 5.3% Grade 3, IFN/RBV-treated patients vs. no IFN/RBV; χ2<0.001) than untreated patients. In addition, we found that the new onset of hypophosphatemia after IFN/RBV treatment initiation was followed by a diminished frequency of this toxicity upon cessation of IFN/RBV, supporting the idea that a drug–drug interaction may increase the risk of this toxicity. To understand the risks of developing this toxicity, we evaluated the association between individual ARV use and hypophosphatemia incidence. Our data suggest that concomitant tenofovir (TDF) use may be a risk factor for the development of hypophosphatemia in HIV/HCV-coinfected patients treated with IFN/RBV. Although the etiology of this abnormality is likely multifactorial, clinicians should be aware of hypophosphatemia as a potential marker of renal toxicity in HIV/HCV-coinfected patients being treated with IFN/RBV regimens.
PMCID: PMC3749689  PMID: 23701022

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