The beneficial effects of polyethylene glycol (PEG)-conjugated therapeutics, such as increased half-life, solubility, stability, and decreased immunogenicity, have been well described. There have been concerns, however, about adverse outcomes with their use, but understanding of those adverse outcomes is still relatively limited. The present study aimed to characterize adverse outcomes associated with PEGylation of protein-based therapeutics on immunogenicity, pharmacologic properties, and safety. A targeted review of English language articles published from 1990 to September 29, 2023, was conducted. Of the 29 studies included in this review, 18 reported adverse safety outcomes such as hematologic complications, hepatic toxicity, injection site reactions, arthralgia, nausea, infections, grade 3 or 4 adverse events (AEs), and AE-related discontinuations and dose modifications. Fifteen studies reported immunogenicity-related outcomes, such as the prevalence of pre-existing antibodies to PEG, treatment-emergent antibody response, and hypersensitivity reactions to PEGylated drugs. Seven studies reported pharmacological outcomes such as increased clearance and reduced activity in response to PEGylated drugs. This review aims to contribute to a balanced view of PEGylated therapies by summarizing the adverse outcomes or lack of benefit associated with PEGylated therapeutics reported in the literature. We identified several studies characterizing adverse outcomes, pharmacological effects, and immunogenicity associated with the use of PEGylated therapeutics. Our findings suggest that using PEGylated therapeutics may require careful monitoring for adverse safety outcomes, including screening and monitoring for pre-existing antibodies and those induced in response to PEGylated therapy, as well as monitoring and adjusting the dosing of PEGylated therapeutics.

Hepatitis C virus (HCV) is a hepatotropic virus that affects millions of human lives worldwide. Direct-acting antiviral (DAA) regimens are the most effective HCV treatment option. However, amino acid substitution-dependent resistance to DAAs has been a major challenge. This study aimed to determine the increasing risk of DAA resistance due to substitutions in DAA target non-structural proteins (NS3/4A, NS5A, and NS5B). Using a Sequence Retrieval System (SRS) at the virus pathogen resource (ViPR/BV-BRC), n = 32763 target protein sequences were retrieved and analyzed for resistance-associated amino acid substitutions (RAASs) by the Sequence Feature Variant Type (SFVT) antiviral-resistance assessment modeling tool. Reference target protein sequences with 100% identity were retried from UniProt following NCBI BLAST. The types and locations of RAASs were identified and visualized by AlphaFold and PyMol. Linux-r-base/R-studio was used for the data presentation. Multi-drug-resistant variants of NS3/4A in genotype 1 (n = 9) and genotype 5 (n = 5) along with DAA-specific NS3/4A, NS5A, and NS5B variants were identified pan-genotypically. A total of 27 variants (RAASs) of all the targets were identified. Fourteen genotype 1-specific substitutions: V1196A, V1158I, D1194A/T/G, R1181K, T1080S, Q1106R, V1062A, S1148G, A1182V, Y2065N, M2000T, and L2003V were identified. The most frequent substitutions were V1062L and L2003M, followed by Q2002H. L2003V, Q2002H, M2000T, Y2065N, and NL2003M of NS5A and L2003M of NS5B conferred resistance to daclatasvir. S2702T NS5B was the sofosbuvir-resistant variant. D1194A NS3/4A was triple DAA (simeprevir, faldaprevir, and asunaprevir) resistant. The double-drug resistant variants R1181K (faldaprevir and asunaprevir), A1182V and Q1106K/R (faldaprevir and simeprevir), T1080S (faldaprevir and telaprevir), and single drug-resistant variants V1062L (telaprevir), D1194E/T (simeprevir), D1194G (asunaprevir), S1148A/G (simeprevir), and Q1106L (Boceprevir) of NS3/4A were determined. The molecular phenomenon of DAA resistance is paramount in the development of HCV drug candidates. RAASs in NS3, NS5A, and NS5B reduce the susceptibility to DAAs; therefore, continuous RAAS-dependent resistance profiling in HCV is recommended to minimize the probability of DAA therapeutic failure.

The hepatitis C virus (HCV) infects more than 180 million people globally, with increasing incidence, especially in developing countries. HCV infection frequently progresses to liver cirrhosis leading to liver transplantation or death, and HCV recurrence still constitutes a major challenge for the transplant team. Antiviral therapy is the only available instrument to slow down this process, although its actual impact on liver histology, in responders and nonresponders, is still controversial. We are now facing a "new era" of direct antiviral agents that is already changing the approach to HCV burden both in the pre- and in the post-liver transplantation settings. Available data on sofosbuvir/ledipasvir and sofosbuvir/simeprevir in patients with decompensated cirrhosis sustain a SVR12 of 89% , but one-third of patients do not clinically improved. The sofosbuvir/ribavirin treatment in stable cirrhotic patients with HCC before liver transplantation is associated with 2% recurrence rate if liver transplantation is performed at least one month after undetectable HCV-RNA is achieved. The treatment of recurrence with the new antiviral drugs is associated with a SVR that ranges between 60 and 90%. In this review, we have focused on the evolution of antiviral therapy for HCV recurrence from the "old" interferon-based therapy to the "new" interferon-free regimens, highlighting useful information to aid the transplant hepatologist in the clinical practice.

Chronic hepatitis C virus (HCV) is the leading cause of liver transplantation (LT) in adults. However, infection of the allograft is universal and associated with reduced graft and patient survival. Although successful eradication improves posttransplant outcome, current antiviral therapies have poor efficacy and tolerability. Direct acting antiviral agents (DAAs) provide new opportunities for treatment of HCV recurrence. The addition of a first-generation NS3/4A protease inhibitor (PI) has increased the efficacy of pegylated interferon and ribavirin in patients with chronic HCV genotype 1 infection. Preliminary efficacy results from open-labeled studies of PI-based triple therapy in LT recipients are encouraging. However, the tolerability of triple therapy is reduced following LT, because of increased anemia and drug-drug interactions. The use of PI-based triple therapy in LT recipients seems best suited to larger centers, experienced with management of PI toxicity. Fortunately, other classes of DAAs targeting different steps of HCV replication are in clinical trials, including nucleotide polymerase (NUC-NS5B) inhibitors, nonnucleotide polymerase (non-NUC-NS5B) inhibitors and NS5A inhibitors. Several dual and triple DAA regimens are in clinical development. Phase II studies conducted in patients before and after LT suggest that these regimens will dramatically reduce the impact of recurrent HCV. There is a tide in the affairs of men. Which, taken at the flood, leads on to fortune (Shakespeare: J Caesar Act 4, scene 3).

Recurrence of HCV after LDLT is almost universal. Different factors affect response to treatment. Few data are available regarding outcome of recurrent HCV genotype 4. The purpose of this study is to improve outcome of recurrent HCV genotype 4 after LDLT.

An IRB approved chart review of 243 patients transplanted for ESLD, HCV genotype 4 over 4 years were reviewed. Protocol liver biopsies were taken 6 months after transplant. Patients received pegylated interferon and ribavirin in case of histological recurrence. Five patients had FCH were excluded.

Thirty-seven patients were included. Sustained Virological Response (SVR) was achieved in 29 (78.3%). Patients with Metavir fibrosis stage (F0) and (F1) had SVR in 5/5 (100%) and 20/24 (83.3%). Two patients with F1 had to stop treatment because of thrombocytopenia and 2 were non responders. Three out of 6 patients (50%) with (F2) had SVR, 2 were non responders and one had to discontinue treatment because of severe depression. One of 2 patients (50%) with F3 had SVR and the other patient decompensated within 4 months before treatment and died.

Protocol biopsies allow early detection of inflammatory changes in the graft before fibrosis occurs. Early treatment of recurrent HCV genotype 4 after LDLT results in better response.

Hepatitis C virus (HCV) is one of the most common causes of chronic liver disease and is currently the leading indication for liver transplantation in the USA. Pegylated IFN-α (PEG-IFN-α) and ribavirin comprise the standard of care for the treatment of chronic HCV. The expansion of antiviral therapy to include special populations that were not well represented or excluded from registration trials has occurred in recent years. Data have emerged that demonstrate that these groups have variable responses to therapy and, in some cases, different side-effect profiles. The etiologies for the varied response rates remain under investigation. This review will address the clinical efficacy and safety profiles of PEG-IFN-α and ribavirin in populations of patients coinfected with HIV, obese patients, liver transplant recipients, children and African-Americans.

In living-donor liver transplant recipients with hepatitis C virus infection, outcomes of recurrent hepatitis C virus infection and fibrosis progression are not well documented. We evaluated fibrosis progression, response to pegylated interferon treatment, and long-term graft survival in living-donor liver transplant recipients who had hepatitis C virus infection.

In 48 transplant recipients, including 29 recipients who had follow-up liver biopsy ≥ 6 months after transplant, histology and clinical courses were reviewed. Outcomes were evaluated for patients grouped into slow and rapid fibrosis groups. Treatment with pegylated interferon and ribavirin was assessed in 18 patients.

Clinical features were similar between recipients with slow or rapid fibrosis. The time interval from transplant to recurrence of hepatitis C virus infection was significantly shorter in the recipients with rapid fibrosis. Recipients with rapid fibrosis had significantly greater confluent necrosis, acidophil bodies, and fibrosis score than recipients with slow fibrosis. Graft survival rates were similar between patients with slow or rapid fibrosis. Cumulative proportion of long-term graft survival was 60% at 7 years after transplant. Sustained virologic response was noted in 5 of 18 patients (28%) who received pegylated interferon and ribavirin.

In recipients of living-donor liver transplant with early recurrence of hepatitis C have worse fibrosis progression but graft survival was not affected. Therapy with pegylated interferon and ribavirin achieved sustained virologic response only in a small proportion of the patients.

To evaluate the effect of long-term treatment with leukocyte natural α-interferon (ln-α-IFN) plus ribavirin (RBV).

Forty-six patients with hepatitis C virus (HCV) recurrence received 3 MU three times a week of ln-α-IFN plus RBV for 1 mo; then, patients with good tolerability (n = 30) were switched to daily IFN administration, while the remaining were treated with the same schedule. Patients have been treated for 12 mo after viral clearance while non-responders (NR) entered in the long-term treatment group. Liver biopsies were planned at baseline, 1 year after sustained virological response (SVR) and at 36 mo after start of therapy in NR. MedCalc software package was used for statistical analysis.

About 16.7% of genotype 1-4 and 70% of genotype 2-3 patients achieved SVR. Nine patients withdrew therapy because of non-tolerance or non-compliance. A significant improvement in serum biochemistry and histological activity was observed in all SVR patients and long-term treated; 100% of patients with SVR achieved a histological response (fibrosis stabilization or improvement) with a significant reduction in mean staging value (from 2.1 to 1.0; P = 0.0031); histological response was observed in 84% of long-term treated patients compared to 57% of drop-out. Six patients died during the entire study period (follow-up 40.6 ± 7.7 mo); of them, 5 presented with severe HCV recurrence on enrollment. Diabetes (OR = 0.38, 95%CI: 0.08-0.59, P = 0.01), leukopenia (OR = 0.54, 95%CI: 0.03-0.57, P = 0.03) and severe HCV recurrence (OR = 0.51, 95%CI: 0.25-0.69, P = 0.0003) were variables associated to survival. Long-term treatment was well tolerated; no patients developed rejection or autoimmune disease.

Long-term treatment improves histology in SVR patients and slows disease progression also in NR, leading to a reduction in liver decompensation, graft failure and liver-related death.

Liver fibrosis results from an excessive wound healing response in most chronic liver diseases, such as hepatitis C. Despite great advances in antiviral therapy in recent years, progressive liver fibrosis remains a major problem for patients with recurrent hepatitis C after liver transplantation. Liver biopsy remains a central tool in the management of HCV-positive liver transplant recipients, but reliable non-invasive methods for the assessment of liver fibrosis, such as ultrasound elastography, are increasingly being incorporated in the management of post-transplant patients, helping predict prognosis, guide treatment decisions, and stratify patients for emerging antifibrotic therapies. In this manuscript, we will review the natural history as well as tools to monitor fibrosis progression in the HCV-positive liver transplant recipient, the mechanisms underlying rapid fibrosis progression in up to 30% of these patients, the effect of antiviral therapies and highlight promising antifibrotic approaches.

Within 5-10 years, 20-40% of hepatitis C virus (HCV)-infected liver transplant recipients can be expected to develop cirrhosis. Here, cost-effectiveness of antiviral therapy was assessed. A Markov model was developed to simulate disease progression and calculate outcome and costs of treatment. In the baseline analysis, Peg-IFN/RBV treatment prevented organ loss/death, gained quality-adjusted life-years (QALYs) and undercut the limit of cost-effectiveness of €50 000/QALY with an incremental cost-effectiveness ratio of approximately €40 400/QALY and €21 000/QALY for HCV genotype 1 and 2/3 patients, respectively. Furthermore, sensitivity analysis testing modified model parameters according to extreme data described in the literature confirmed cost-effectiveness for a lower or higher rate of fibrosis progression, increased non-HCV-related mortality, lower limits of utilities, a time horizon of 30 years, and additional costs in the year of death. On the other hand, cost-effectiveness was lost for patients with genotype 1 in case of doubled antiviral or life-time costs or an increased discount rate of 7%. New treatment strategies for HCV genotype 1 infected patients remained on the same level cost-effective, if additional costs did not exceed €10 774 per 10% sustained virologic response gain. We conclude that Peg-IFN/RBV treatment is cost-effective post transplant. This may support treatment decision in individual cases.

Hepatitis-C-virus- (HCV-) related end-stage cirrhosis is the primary indication for liver transplantation in many countries. Unfortunately, however, HCV is not eliminated by transplantation and graft reinfection is universal, resulting in fibrosis, cirrhosis, and finally graft decompression. In areas with low deceased-donor organ availability like Japan, living-donor liver transplantation (LDLT) is similarly indicated for HCV cirrhosis as deceased-donor liver transplantation (DDLT) in Western countries and accepted as an established treatment for HCV-cirrhosis, and the results are equivalent to those of DDLT. To prevent graft failure due to recurrent hepatitis C, antiviral treatment with pegylated-interferon and ribavirin is currently considered the most promising regimen with a sustained viral response rate of around 30% to 35%, although the survival benefit of this regimen remains to be investigated. In contrast to DDLT, many Japanese LDLT centers have reported modified treatment regimens as best efforts to secure first graft, such as aggressive preemptive antiviral treatment, escalation of dosages, and elongation of treatment duration.

The aim of this study was to evaluate the factors affecting the response to treatment and how it could affect survival in a large series of genotype-1 HCV-transplanted patients. Three-hundred and twenty six genotype-1 HCV patients were enrolled. One hundred and ninety-six patients (60.1%) were nonresponders and 130 (39.9%) showed negative HCV-RNA at the end of treatment. Eighty-four of them (25.8%) achieved sustained virological response, while 46 (14.1%) showed viral relapse. Five-year cumulative survival was significantly worse in nonresponders (76.4%) compared with sustained viral response (93.2) or relapsers (94.9%). Sustained responders and relapsers were therefore considered as a single 'response group' in further analysis. Pretreatment variables significantly associated with virological response at multivariate regression analysis were the absence of ineffective pretransplant antiviral therapy, the recurrence of HCV-hepatitis more than 1 year after transplant, an histological grading ≥4 at pretreatment liver biopsy, a pretreatment HCV-RNA level <1.2 × 10(6 ) IU/ml, and the absence of diabetes. As expected, also on-treatment variables (rapid and early virological response) were significantly associated to the response to antiviral treatment. In conclusion, this study shows that postliver transplant antiviral treatment results in beneficial effect on survival not only in sustained responders but also in relapsers.

Hepatitis C related liver failure and hepatocarcinoma are the most common indications for liver transplantation in Western countries. Recurrent hepatitis C infection of the allograft is universal and immediate following liver transplantation, being associated with accelerated progression to cirrhosis, graft loss and death. Graft and patient survival is reduced in liver transplant recipients with recurrent Hepatitis C virus (HCV) infection compared to HCV-negative recipients. Many variables may impact on recurrent HCV liver disease. Overall, excess immunosuppression is believed to be a key factor; however, no immunosuppressive regimen has been identified to be more beneficial or less harmful. Donor age limitations, exclusion of moderately to severely steatotic livers and minimization of ischemic times could be a potential strategy to minimize the severity of HCV disease in transplanted subjects. After transplantation, antiviral therapy based on pegylated IFN alpha with or without ribavirin is associated with far less results than that reported for immunocompetent HCV-infected patients. New findings in the field of immunotherapy and genomic medicine applied to this context are promising.

Hepatitis-C-virus- (HCV-) related end-stage cirrhosis is the primary indication for liver transplantation in many countries. Unfortunately, however, HCV is not eliminated by transplantation and graft reinfection is universal, resulting in fibrosis, cirrhosis, and finally graft decompensation. The use of poor quality organs, particularly from older donors, has a highly negative impact on the severity of recurrence and patient/graft survival. Although immunosuppressive regimens have a considerable impact on the outcome, the optimal regimen after liver transplantation for HCV-infected patients remains unclear. Disease progression monitoring with protocol biopsy and new noninvasive methods is essential for predicting patient/graft outcome and starting antiviral treatment with the appropriate timing. Antiviral treatment with pegylated interferon and ribavirin is currently considered the most promising regimen with a sustained viral response rate of around 30% to 35%, although the survival benefit of this regimen remains to be investigated. Living-donor liver transplantation is now widely accepted as an established treatment for HCV cirrhosis and the results are equivalent to those of deceased donor liver transplantation.

In November 2010, the Spanish Society of Liver Transplantation (Sociedad Española de Trasplante Hepático, SETH) held a consensus conference. One of the topics of debate was liver transplantation in patients with hepatitis C. This document reviews (i) the natural history of post-transplant hepatitis C, (ii) factors associated with post-transplant prognosis in patients with hepatitis C, (iii) the role of immunosuppression in the evolution of recurrent hepatitis C and response to antiviral therapy, (iv) antiviral therapy, both before and after transplantation, (v) follow-up of patients with recurrent hepatitis C and (vi) the role of retransplantation.

Recurrent hepatitis C infection in the posttransplant setting is a serious problem. The aim of this study was to evaluate the efficacy, safety, indications, optimal time of administration and adequate duration of antiviral therapy with pegylated interferon alpha 2 b (PEG-IFN) and ribavirin (RIB).

Between 2003 and 2009, 16 patients received antiviral therapy (PEG-IFN: 0.8-1.6 μg/kg/wk, RIB 800-1200 mg/d) for at least 6 months. Patients with a biochemical without a virologicalresponse after 12 months of therapy received antiviral treatment for a further 6 months. Hepatitis C virus load was determined at 1, 3, 6, and 12 months after start of therapy. Liver biopsy was performed in all patients before the beginning and after the end of treatment.

The mean period of antiviral therapy was 14 months. The four patients who received the full-length treatment (12 months, 33%) showed sustained virological responses (SVR) and 8 showed virological and biochemical responses (VR, BR). Patients with SVR showed significant improvement in the grading and staging of HAI (histological activity index; P=.03). Nine patients had several side effects under antiviral treatment. Acute rejection episodes were not observed.

The antiviral treatment combination using PEG-IFN and RIB for recurrent hepatitis C is effective procedure. The SVR of 33% after 12 months of treatment with significant improvement in HAI grading and staging and stable HAI in all treated patients favor early initiation and 12-month administration of antiviral treatment. Furthermore, all patients with BR without VR, who underwent antiviral treatment for a further 6 months, achieved a VR. However, the optimal duration of treatment needs to be investigated in large prospective studies.

Approximately 30% of patients who have recurrent hepatitis C after liver transplantation achieve sustained virological response (SVR) by taking a combination therapy of pegylated interferon and ribavirin. For the remaining non-SVR patients, an effective management treatment has not yet been established. In this study, efficacy of long-term peginterferon maintenance therapy for non-SVR patients was evaluated. Forty patients who had previously received the combination therapy for hepatitis C after living donor liver transplantation were classified into one of the following three groups: the SVR group (n = 11); the non-SVR-IFN group (n =17), which received low-dose peginterferon maintenance therapy for non-SVR patients; and the non-SVR-Withdrawal group (n = 12), which discontinued the interferon treatment. We then compared histological changes among these three groups after 2 or more years follow-up. Activity grade of liver histology improved or remained stable in patients in the SVR and non-SVR-IFN groups, but deteriorated in half of the patients in the non-SVR-Withdrawal group. Fibrosis improved or remained stable in 10 of 11 SVR patients and in 13 of 17 non-SVR-IFN patients, but deteriorated in all non-SVR-Withdrawal patients. Mean changes in fibrosis stage between pretreatment and final liver biopsy were -0.18, +0.06 and +2.2 in the SVR, non-SVR-IFN and non-SVR-Withdrawal groups, respectively. Fibrosis stage deteriorated to F3 or F4 significantly more rapidly in the non-SVR-Withdrawal group than in the other two groups. In conclusion, continuing long-term maintenance therapy with peginterferon prevented histological progression of hepatitis C in patients who had undergone living donor liver transplantation.

Recurrence of hepatitis C virus remains a near-universal phenomenon after liver transplantation (LT) and is responsible for the high morbidity and low survival seen in these patients. The severity of recurrent disease varies depending on multiple factors, only some of which are modifiable. Antiviral therapy is associated with improved outcomes, but viral clearance is only attainable in a small percentage of this patient population. This patient population is in need of new therapeutic options, and it remains to be seen whether direct-acting antiviral agents will be the answer to this ongoing therapeutic question.

The influence of immunosuppression on the response to antiviral treatment in recurrent hepatitis C is still under debate. The purpose of this study was to identify those factors that might predict sustained viral response and relapse.

The ReViS-TC, a multicenter cohort study conducted in 14 Spanish liver centers, included data from liver transplant recipients from January 2000 to December 2006 who had recurrent hepatitis C virus and who had undergone antiviral treatment with pegylated interferon plus ribavirin. Sustained virological response (SVR) and viral relapse were evaluated. A multivariate logistic regression model was used to investigate host, donor, and therapeutic factors associated with SVR and relapse.

The analysis included 410 patients, 30% treated with cyclosporine A (CsA) and 70% with tacrolimus. SVR was achieved in 48% of patients with CsA and in 37% with tacrolimus (P=0.037), with a relapse rate of 18% and 36%, respectively (P=0.008). In the multivariate model, the administration of CsA (odds ratio [OR] 0.37, P=0.021) in conjunction with a longer antiviral treatment duration (OR 0.86, P=0.024) correlated with lower relapse rate, whereas the older age of the donor (OR 1.03, P=0.006) and the presence of genotype 1 (OR 3.45, P=0.032) were associated with a higher probability of relapse.

Our results suggest that the use of CsA-based immunosuppression regimens and longer treatment duration may protect patients against viral relapse after a positive response to pegylated interferon plus ribavirin therapy. These data need to be further confirmed in clinical trials.

A significant proportion of patients with chronic hepatitis C virus (HCV) infection develop liver cirrhosis and complications of end-stage liver disease over two to three decades and require liver transplantation, however, reinfection is common and leads to further adverse events under immunosuppression. Pretransplant antiviral or preemptive therapy is limited to mildly decompensated patients due to poor tolerance. The mainstay of management represents directed antiviral therapy after evidence of recurrence of chronic hepatitis C. Combined pegylated interferon and ribavirin therapy is the current standard treatment with sustained viral response rates of 25% to 45%. The rate is lower than that in the immunocompetent population, partly due to the high prevalence of intolerability. To date, there is no general consensus regarding the antiviral treatment modality, timing, or dosing for HCV in patients with advanced liver disease and after liver transplantation. New anti-HCV drugs to delay disease progression or to enhance viral clearance are necessary.

The current therapy for hepatitis C recurrence after liver transplantation OLT is based on interferon (IFN) and ribavirin (RBV) in monotherapy or combination. The rate of sustained virological response (SVR) varies between 10% and 45%. We have retrospectively analyzed factors that could predict SVR after antiviral therapy. We analyzed 42 patients who completed a cycle of therapy with natural or pegylated IFN plus RBV. There were 15 (35.7%) patients who obtained an SVR. The following factors were significantly associated with a lack of SVR: donor age >or=50 years (P = .046); donor body mass index (BMI) > 27 (P = .016); genotype 1 versus 2 to 3 (P = 0.010), aspartate transferase (AST) before therapy >or= 140 U/L (P = .046), alanine transferase before therapy >or= 280 U/L (P = .055), use of natural IFN versus pegylated IFN (P = .016). The only factors remaining after multivariate analysis were: donor BMI, AST before therapy and genotype. Our data confirmed that genotype 1 was associated with poorer outcomes; other additional parameters can influence the response to antiviral therapy.

Liver transplantation is currently the definitive treatment of end-stage liver disease. This article reviews the complex multidisciplinary care of the liver transplant recipient beginning immediately after transplantation but extending into the long term. The presentation, evaluation and treatment of common post-transplant complications are outlined. Importantly, immunosuppression strategies along with the issues of acute and chronic rejection are discussed in detail with an emphasis on how practice has evolved over time. The spectrum of infectious problems is systematically presented, based on the time since transplantation and the institution of immunosuppression. Finally, the substantial challenges of recurrent disease and long-term medical comorbidities are addressed as these are clearly the primary issues that threaten the longevity and wellbeing of the liver transplant recipient.

We hypothesized that antiviral efficacy [sustained virologic response (SVR)] has improved in recent years in the transplant setting. Our aim was to assess whether the efficacy of pegylated interferon (PegIFN)-ribavirin (Rbv) has improved over time. One hundred seven liver transplant patients [74% men, 55.5 years old (range: 37.5-69.5), 86% genotype 1a or 1b] were treated with PegIFN-Rbv for 355 (16-623) days at 20.1 (1.7-132.6) months after transplantation. Tacrolimus was used in 61%. Sixty-seven percent had baseline F3-F4 (cirrhosis: 20.5%). Donor age was 49 (12-78) years. SVR was achieved in 39 (36.5%) patients, with worse results achieved in recent years (2001-2003: n = 27, 46.5%; 2004: n = 23, 43.5%; 2005: n = 21, 35%; 2006 to January 2007: n = 36, 24%; P = 0.043). Variables associated with SVR in the univariate analysis included donor age, baseline viremia and cirrhosis, bilirubin levels, rapid virologic response and early virologic response (EVR), premature discontinuation of PegIFN or Rbv, and accumulated Rbv dose. In the multivariate analysis, the variables in the model were EVR [odds ratio (OR): 0.08, 95% confidence interval (CI): 0.016-0.414, P = 0.002] and donor age (OR: 1.039, 95% CI: 1.008-1.071, P = 0.01). Variables that had changed over time included donor age, baseline viremia, disease severity (cirrhosis, baseline bilirubin, and leukocyte and platelet counts), interval between transplantation and therapy, and use of growth factors. In the multivariate analysis, variables independently changing were donor age (OR: 1.041, 95% CI: 1.013-1.071, P = 0.004), duration from transplantation to antiviral therapy (OR: 1.001, 95% CI: 1.000-1.001, P = 0.013), and baseline leukocyte count (OR: 1.000, 95% CI: 1.000-1.000, P = 0.034). In conclusion, the efficacy of antiviral therapy with PegIFN-Rbv has worsened over time, at least in our center. The increase in donor age and greater proportion of patients treated at advanced stages of disease are potential causes.

Pegylated interferon with ribavirin (Peg/R) is the most effective therapy for chronic hepatitis C virus (HCV) but its utility and effectiveness after liver transplantation has been difficult to assess. We evaluated efficacy, tolerability, and safety of Peg/R in liver transplant candidates and recipients with HCV cirrhosis. We searched medical databases and conference proceedings between January 1999 and January 2008 selecting randomized and nonrandomized studies. Primary end points meta-analytically were: (1) sustained viral response (SVR) and (2) histological response. Secondary end points were: (1) treatment discontinuation, (2) mortality, and (3) rejection episodes. Pegylated interferons using either 1-1.5 mcg/kg of pegylated interferon alpha-2b or 180 microg (pegylated interferon alpha-2a combined with ribavirin 800-1200 mg/day were the most effective compared to any other regimen or no therapy. In three pretransplant studies the median SVR was 19.6% (19.6-50%). In six postransplant studies where a meta-analysis was done the cumulative risk difference in SVR was 0.31% (95% CI, 0.18-0.44, p < 0.001). However histological response was not significantly better compared to no therapy or other antiviral regimens. There were no significant differences in discontinuation of therapy, acute or chronic rejection or mortality between optimal Peg/R vs no treatment or other regimens. Hence pegylated interferon plus ribavirin in full doses is effective pre and post transplant but has a low SVR rate. To date no significant histological improvement has been reported.

Treatment of hepatitis C virus (HCV) recurrence after liver transplantation (LT) is difficult with low response rates.

To assess the safety and efficacy of pegylated-interferon (PEG-IFN) alfa-2b + ribavirin (RBV) in patients with post-LT recurrent genotype-1 HCV and to establish stopping rules according to response.

Fifty-three patients with post-LT HCV recurrence were enrolled. Patients received PEG-IFN alfa-2b 1.0 micro/kg/week plus RBV 8-10 mg/kg/day for 24 weeks. Those with 'early virological response at week 24' (EVR24) continued treatment for 24 weeks (group A). Patients without EVR24 were randomized to continue (group B) or to discontinue (group C).

Overall sustained virological response (SVR) was 26% (14/53). Alanine aminotransferase, rapid virological response, EVR12, EVR24, undetectable serum HCV-RNA at weeks 12 (cEVR12) and 24 (cEVR24) were related to SVR. cEVR12 and cEVR24 (OR: 14.7; 95% CI: 2.02-106.4) were independent predictors of SVR. All patients with SVR, had cEVR12. No patient in groups B and C achieved end-of-treatment response. One patient in group B had SVR.

Pegylated-interferon alfa-2b was effective in one of four of patients with HCV genotype 1 after LT. Treatment should be discontinued in patients with no virological response at week 12. Further studies are needed to evaluate whether a longer treatment period may be beneficial in patients with > or =2 log10 drop in HCV-RNA at week 24.

Hepatitis C (HCV)-related end-stage liver disease is the most common indication for liver transplantation. Safe expansion of the donor pool with improved rates of deceased donation and more widespread use of living and extended criteria donation are likely to decrease wait list mortality. In addition, improved antiviral treatments and a better understanding of the delicate balance between under- and over-immunosuppression in this population are needed. Finally, when recurrent advanced fibrosis occurs, the criteria for patient selection for retransplantation remain widely debated. This article reviews the literature on these topics and the work being done in each area to maximize outcomes in patients receiving transplants for HCV-related cirrhosis.

The aim of our study was to conduct a systematic review of studies evaluating antiviral therapy with pegylated interferon (PEG-IFN) alfa in combination with ribavirin for the management of recurrent hepatitis C after liver transplantation. Data sources included electronic databases and a manual search. Studies evaluating the efficacy and tolerability of PEG-IFN alfa with ribavirin in patients with recurrent hepatitis C were selected for inclusion. The information extracted from each of the selected publications included study design details, patient characteristics, treatment regimens and efficacy and tolerability end points. Nineteen studies including 611 patients were identified. PEG-IFN alfa-2b was used in 16 studies. The mean rate of SVR was 30.2% (range, 8-50%). Dose reduction and discontinuation of treatment were common in these studies (73% and 27.6%, respectively). The lack of an early virologic response (EVR) at 3 months of therapy was the most frequently described predictive factor of nonresponse. Treatment discontinuation and dose reductions due to adverse events were frequent and possibly represent important obstacles to attainment of SVR. EVR at 3 months of treatment should be considered an important predictor of treatment outcome.

To investigate the efficacy of two anti-viral protocols in hepatitis C virus-reinfected liver transplant recipients.

In this prospective study, 26 liver transplant patients were treated with standard interferon-alpha2b for 12 months or standard interferon-alpha2b for 3 months followed by pegylated interferon-alpha2b for 9 months. Interferon was combined with ribavirin in all patients. The histological course of the study population was compared with an untreated historic control group (n = 38) with similar baseline characteristics.

The sustained virological response rates in the standard interferon group and in the pegylated interferon group were 27.3% and 26.7%, respectively. Only 29% of patients with sustained virological response had end of treatment histological response, whereas 47% of viral non-responders showed end of treatment histological response. The percentage of patients with histological improvement was significantly higher in the study population when compared to the controls. Univariate analysis indicated that hepatitis C virus genotype non-1, high baseline alanine aminotransferase, the time interval between liver transplant and interferon therapy and the body mass index predicted sustained virological response. In the multivariate model, baseline alanine aminotransferase and the body mass index remained a significant predictor of sustained virological response.

Both treatment regimens offer similar efficacy profiles. Failure to eradicate hepatitis C virus should not lead to treatment discontinuation if serial liver biopsies demonstrate histological response.

Hepatitis C virus (HCV) is a leading cause of chronic hepatitis, with 170 to 190 million people infected worldwide. The treatment of choice for patients who have HCV-related cirrhosis with or without hepatocellular carcinoma is liver transplantation. Virologic recurrence is constant after transplantation and results in chronic hepatitis in the vast majority. HCV infection now can be cured in a substantial proportion of liver transplant recipients. This review highlights the available strategies to improve outcome, including modification of factors that affect disease progression and the efficacy of antiviral therapy.

Anemia is a common side effect that begins soon after the initiation of peginterferon/ribavirin in the treatment of hepatitis C virus (HCV) infection. It can cause symptoms that negatively impact quality of life (QOL) and is the most common reason for reducing the dose and temporarily or permanently discontinuing ribavirin. Such dose modifications have been shown to reduce the efficacy of treatment. Administering erythropoietin can improve anemia caused by peginterferon and ribavirin therapy and is more effective than dose reduction at improving QOL during treatment. However, erythropoietin, which is not approved by the U.S. Food and Drug Administration (FDA) for use in patients with HCV infection, adds another parenteral drug to the patient's treatment regimen, and is associated with additional costs, inconvenience, and potential side effects. A new ribavirin analog, viramidine, is expected to be associated with a lower incidence of anemia and, if proven effective, may eventually be substituted for ribavirin in combination with peginterferon to treat chronic hepatitis C. In the meantime, physicians must make the best possible use of the available options for managing anemia, especially in select patient groups who are most at risk for anemia and its complications.

HCV infection recurs almost in all HCV-positive patients receiving liver transplantation and carries a poor prognosis. Aim of this study was to analyze efficacy and effect on survival of antiviral therapy in this clinical setting.

Pegylated-interferon alpha-2b and ribavirin were administered at a dose of 1 microg/kg of bwt weekly and 600-800 mg/day. Planned duration of treatment was 24 or 48 weeks according to HCV genotype. Patients who failed to respond at week 24 were considered as non-responders.

61 patients were enrolled. According to intention-to-treat analysis, 44 (72%) patients were considered as treatment failure (31 non-responders, 4 relapsers, 9 dropout). Sustained virological response was achieved in 17 cases (28%). Genotype 2, higher doses of antivirals and absence of histological cirrhosis were predictors of sustained virological response. In the follow up, patients with sustained virological response had a significantly lower mortality compared to patients with treatment failure (chi2=6.9; P<0.01).

Response rate to antiviral therapy in HCV reinfection after liver transplantation is higher if a full dose of antiviral drugs is administered and if treatment starts before histological cirrhosis has developed. Sustained virological response improves patient survival.

Approximately 400 liver transplants are performed in Canada every year and close to 6000 per year in the United States. Forty per cent to 45% of all liver transplants are performed for patients with underlying hepatitis C virus (HCV)-related liver disease. These patients have a different natural history, new complication risks and different treatment efficacy than nontransplant HCV patients. Every effort must be made to identify those patients at highest risk for progressive liver disease post-transplant. Recurrent HCV is an Achilles' heel to transplant hepatology. The true natural history of this disease is only starting to unravel and many questions remain unanswered on the optimal management of these patients after liver transplantation. The present report summarizes the literature and ongoing research needs that are specific to HCV-related liver transplantation.

Today, combination antiviral therapy with pegylated interferon-alpha and ribavirin (RBV) allows many patients infected with hepatitis C virus (HCV) to achieve a sustained virological response, which is equivalent to cure. Data also support the clinical benefit of combination antiviral therapy in patients coinfected with HCV and HIV, and in patients who have received a liver transplant. Antiviral therapy with pegylated interferon-alpha and RBV is, however, associated with a high incidence and significant magnitude of anemia. This anemia may have several mechanisms, including bone marrow suppression and hemolysis. In addition, patients coinfected with HIV may have both pre-existing and RBV-associated anemia. Management of anemia in patients with HCV through RBV dose reduction or treatment discontinuation may compromise the effectiveness of treatment, because studies have demonstrated that treatment adherence or maintenance of antiviral therapy dose is an important predictor of sustained virological response. Anemia associated with combination antiviral therapy in patients with HCV is frequently associated with an inadequate or blunted endogenous erythropoietin response. Accumulating evidence now supports the use of recombinant human erythropoietin (rHuEpo) to manage anemia in these patients, with the objective of maintaining the RBV dose, but clinical standards are lacking. The present article reviews the data relevant to the use of rHuEpo in this patient population and proposes a set of clinical practice standards to assist clinicians in selecting patients for rHuEpo and in implementing rHuEpo therapy effectively.

Hepatitis C virus (HCV) infection remains the most common cause of hepatic failure requiring orthotopic liver transplantation, and the disparity between the number of patients in need of liver replacement and the number of organs available continues to grow. Unfortunately, without viral eradication before transplantation, HCV recurrence is universal and is associated with poor graft and patient survival. Despite expansion of the donor pool and attempts to suppress HCV activity with various pretransplant and posttransplant antiviral therapies, many questions remain. This article reviews the literature regarding the evaluation of patients for transplantation, the antiviral therapies available in the peritransplant period, the immunosuppressive regimens, used, and the approach to patients with recurrent HCV infection.

Therapy of hepatitis C virus (HCV) infection may prevent progression to cirrhosis, hepatocellular carcinoma and end-stage liver disease. The cornerstone of treatment has long been standard IFN-alpha, the use of which was associated with a sustained biochemical and viral response in only a small proportion of patients. More recently, the success of interferon-based regimens has substantially improved due to the combination with the guanosine analogue ribavirin and to the advent of pegylated interferon formulations. However, even the most up-to-date regimens fail to cure the infection in many cases and are limited by side effects and high costs. A better understanding of the HCV genomic organisation, the elucidation of the three-dimensional structures of virally encoded enzymes and the recent development of a HCV-replicon system in human hepatoma (Huh-7) cells have led to significant advances in the development of new antiviral compounds, many of which are under evaluation in clinical trials. The aim of this review is to trace a brief overview of the progress made by interferon-based treatments for hepatitis C since their introduction in the early 1990s, and to highlight the results of recent clinical studies concerning new and emerging drugs.

Hepatitis C recurrence after liver transplantation (LT) is universal, and frequently leads to cirrhosis and death. The aim of our study was to assess the efficacy and safety of 48-weeks of full-dose peg-interferon-alpha-2a (n = 4) or alpha-2b (n = 51) plus ribavirin (>11 mg/kg/day) in a multicentric cohort of 55 patients > or =12 months after LT. All subjects had histologically proven HCV recurrence, excluding severe cholestatic recurrence. Mean age was 54.3 +/- 9.7, 77% male, 90.9% genotype 1, 32.7% cirrhotics. All but 5 patients received monotherapy with tacrolimus (54.5%), cyclosporine (30.7%) or mycophenolate mofetil (5.5%). The rates of end-of-treatment response and sustained virological response (SVR) were 66.7% and 43.6%, respectively. Low baseline HCV-RNA (p = 0.005) and a length from LT to therapy between 2-4 years (p = 0.011) were predictors of SVR. The lack of achieving a viral load decrease > or =1-log10 at week 4 and/or 2-log10 at week 12 was 100% predictive of failure. The most frequent side effects were neutropenia (76,4%), anemia (60%) and infectious complications (30.9%). Toxicity led to peg-interferon withdrawal in 16 (29%) subjects. In 15 patients with post-treatment biopsy, the histological activity index was significantly improved (p = 0.006), whereas fibrosis did not change (p = 0.14). Three patients died (cholangitis, hepatic artery thrombosis and lung cancer). In conclusion, HCV therapy after LT was very effective, although it led to a significant rate of toxicity.

Chronic infection with hepatitis C virus (HCV) is a growing problem worldwide, with up to 300 million individuals infected, and those with chronic infection are at risk for cirrhosis and hepatocellular carcinoma. HCV infection is the most common indication for liver transplantation in the United States and Europe. Unfortunately, although transplantation is effective for treating decompensated cirrhosis and limited hepatocellular carcinoma associated with hepatitis C, HCV reinfection is virtually the rule among transplant recipients. Reinfection of the graft is associated with more rapidly progressive disease, with a median time to cirrhosis of 8 to 10 yr. Unfortunately, treatment of chronic HCV in liver transplant recipients is suboptimal. Combination therapy with interferon (pegylated and nonpegylated forms) plus ribavirin appears to provide maximum benefits. Drug therapy is usually administered for recurrent disease. No prophylactic therapy is available. Preemptive regimens offer no distinctive advantages over treatments begun for recurrent disease. Overall, treatment is poorly tolerated, with frequent need for dose reductions, especially from cytopenias, and drug discontinuations in up to 50% of patients. Optimizing drug doses is important in maximizing sustained virological response rates. Future therapies may include ribavirin alternatives with lower rates of anemia, alternative interferons with lower rates of cytopenias, and new antiviral drugs that can be used alone or in combination with either interferon or ribavirin to enhance sustained virological response rates and improve tolerability. Liver Transpl 12:1192-1204, 2006. (c) 2006 AASLD.

Recurrence of hepatitis C virus (HCV) infection after liver transplantation (LT) is universal. However, the efficacy, tolerability and safety of combination interferon and ribavirin (IFN-RIB) or peginterferon and ribavirin (PEG-RIB) anti-viral therapies post-LT are uncertain. We performed a comprehensive search of major medical databases (1980-2005) and conference proceedings (1996-2005). The main outcome measure was sustained virological response (SVR, undetectable HCV RNA) at 6 months. Summary estimates were calculated using random-effects models. Twenty-seven IFN-RIB and 21 PEG-RIB studies were included. IFN-RIB was associated with a pooled SVR rate of 24% (95% CI, 20-27%), while PEG-RIB was associated with an SVR rate of 27% (23-31%). Pooled discontinuation rates were 24% (21-27%) with IFN-RIB and 26% (20-32%) with PEG-RIB. The pooled rate of acute graft rejection was 2% (1-3%) with IFN-RIB and 5% (3-7%) with PEG-RIB. IFN-RIB and PEG-RIB therapies in HCV infection post-LT were associated with similar but overall low SVR and were poorly tolerated. The rate of acute rejection was small. The therapeutic advantage of PEG-RIB therapy observed in non-transplant chronic HCV infection appears to be attenuated post-LT. Clinical trials are needed to evaluate reasons for this post-transplant therapeutic disadvantage and to find strategies to ameliorate them.

Patients with recurrent hepatitis C virus (HCV) are often treated with interferon-based therapy in an attempt to eradicate HCV and prevent cirrhosis requiring retransplantation. We describe our experience with pegylated interferon and ribavirin and the impact of this therapy on hepatic fibrosis.

Patients were treated with pegylated interferon alpha-2b 1.5 mcg/kg/week and ribavirin 800 mg/day for 6-12 months according to genotype. HCV ribonucleic acid (HCV RNA) was repeated at 3 months, end of treatment (EOT) and 6 months after EOT for patients HCV RNA negative at EOT. Liver biopsies were performed prior to treatment and at EOT.

Thirty nine patients were eligible. Twenty two completed treatment and 17 (43.6%) were intolerant. Eleven of 22 (50%) patients who completed treatment developed sustained viral response (SVR). Two patients intolerant to treatment also developed SVR. Serial biopsies were performed in 17 patients and refused in five. Improved fibrosis scores were present in four patients (non-responders, n = 2), unchanged in 10 (non-responders, n = 4), and worse in three (all non-responders).

Side effects are an important limiting factor in recurrent HCV treatment with SVR only 33.3% in an intention-to-treat analysis. However, improved or stable fibrosis scores were also demonstrated in 66.7% of non-responders. This suggests failure to eradicate HCV should not necessarily lead to treatment discontinuation as a subgroup of patients may benefit from maintenance therapy.

Chronic hepatitis C is a principal indication for liver transplantation. Recurrent viral infection is inevitable and graft disease is common. We report tolerability, safety and efficacy of pegylated interferon alpha 2b (PEG-IFN) monotherapy for patients with hepatitis C virus (HCV) recurrence and fibrosis after liver transplantation. Repeated measurements of serum HCV titer permitted assessment of the kinetics of the antiviral response for all patients. We screened 63 patients transplanted for HCV at our center for antiviral treatment, 14 were eligible and treated, but only 6 completed the proposed 52 weeks of therapy. Eight were withdrawn because of severe/life-threatening side effects/events, including liver dysfunction (4 patients). None of those 8 achieved a sustained virological response (SVR). Five of 6 who completed treatment were HCV RNA negative at the end of treatment, and 2 achieved an SVR. Viral kinetics were similar to published observations for treatment of non-transplanted HCV patients. Patients with genotype non-1 infection displayed a more rapid decline of viral titer than was observed for genotype 1 infection. Post-transplant HCV patients are frequently unsuitable for, or intolerant of PEG-IFN. Liver dysfunction was a major concern.

Hepatitis C recurs on grafts after liver transplantation and cirrhosis develops more rapidly than in patients without transplants. It is thus essential to develop effective antiviral treatments for these patients. Prolonged virologic response rate after treatment by pegylated interferon and ribavirin of recurrent HVC is limited, because so many patients stop or reduce the treatment because, in particular, of profound anemia. Administration of erythropoietin can enable these patients to continue treatment and thus improve viral eradication.

We report three cases where antiviral treatment continued although the clinical data would, in the absence of erythropoietin, have led us to interrupt it and where prolonged virologic response was obtained.

These data suggest that the onset of anemia largely explains the failure of previous trials, although response to treatment is at least as good as in non-transplanted patients, despite immunosuppressive treatment.

Liver transplantation is a life-saving therapy to correct liver failure, portal hypertension and hepatocellular carcinoma arising from hepatitis C infection. But despite the successful use of living donors and improvements in immunosuppression and antiviral therapy, organ demand continues to outstrip supply and recurrent hepatitis C with accelerated progression to cirrhosis of the graft is a frequent cause of graft loss and the need for retransplantation. Appropriate selection of candidates and timing of transplantation, coupled with better pre- and post-transplant antiviral therapy, are needed to improve outcomes.