Real-world hepatitis C prevalence and treatment uptake at opioid agonist therapy clinics in Ontario, Canada.

Widespread screening for hepatitis C virus (HCV) is necessary for Canada to meet its HCV elimination goals by 2030. People who currently or previously injected drugs are at high risk for HCV. Opioid agonist therapy (OAT, such as methadone and buprenorphine) has been shown to help stabilize the lives of people who are opioid-dependent. The distribution of OAT in North America typically requires daily, weekly, or monthly clinic visits and presents an opportunity for engagement, screening and treatment for those at high-risk of HCV. In this study, HCV screening was conducted by staff at OAT clinics in Ontario from 2016 to 2020 and those with chronic infections were treated on-site with direct-acting antivirals. Point-of-care or dried blood spot (DBS) testing was used for antibodies, DBS or serum for HCV RNA and serum for HCV RNA at SVR12 (sustained virological response). Clinics screened 1954 people (mean age 40 years ±12, 63% male). Forty-five percent were antibody positive, of whom 64% were HCV RNA+. Eighty percent of those RNA+ set an appointment in which 99% attended. Ninety-six percent started treatment with 87% completing treatment. Sixty-eight percent of people who completed treatment submitted a sample for SVR12 testing of which 97% achieved a virological cure. Results suggest that HCV screening and treatment at OAT clinics is feasible, effective and warrants expansion. Data suggest strong treatment adherence due to high rates of SVR12 comparable with other OAT-based HCV treatment programs. The lack of SVR12 sampling could be addressed by either on-site phlebotomy or incentivizing SVR12 sampling.

Estimating chronic hepatitis C prognosis using transient elastography-based liver stiffness: A systematic review and meta-analysis.

Chronic hepatitis C (CHC) is a leading cause of hepatic fibrosis and cirrhosis. The level of fibrosis is traditionally established by histology, and prognosis is estimated using fibrosis progression rates (FPRs; annual probability of progressing across histological stages). However, newer noninvasive alternatives are quickly replacing biopsy. One alternative, transient elastography (TE), quantifies fibrosis by measuring liver stiffness (LSM). Given these developments, the purpose of this study was (i) to estimate prognosis in treatment-naïve CHC patients using TE-based liver stiffness progression rates (LSPR) as an alternative to FPRs and (ii) to compare consistency between LSPRs and FPRs. A systematic literature search was performed using multiple databases (January 1990 to February 2016). LSPRs were calculated using either a direct method (given the difference in serial LSMs and time elapsed) or an indirect method given a single LSM and the estimated duration of infection and pooled using random-effects meta-analyses. For validation purposes, FPRs were also estimated. Heterogeneity was explored by random-effects meta-regression. Twenty-seven studies reporting on 39 groups of patients (N = 5874) were identified with 35 groups allowing for indirect and 8 for direct estimation of LSPR. The majority (~58%) of patients were HIV/HCV-coinfected. The estimated time-to-cirrhosis based on TE vs biopsy was 39 and 38 years, respectively. In univariate meta-regressions, male sex and HIV were positively and age at assessment, negatively associated with LSPRs. Noninvasive prognosis of HCV is consistent with FPRs in predicting time-to-cirrhosis, but more longitudinal studies of liver stiffness are needed to obtain refined estimates.

Efficacy and safety of 6 or 8 weeks of simeprevir, daclatasvir, sofosbuvir for HCV genotype 1 infection.

The phase 2, open-label ACCORDION (ClinicalTrials.gov: NCT02349048) study investigated the efficacy, safety and pharmacokinetics of a 6- or 8-week regimen of simeprevir, daclatasvir and sofosbuvir in treatment-naïve patients with chronic hepatitis C virus (HCV) genotype (GT) 1 infection and either early-stage fibrosis or compensated cirrhosis. Patients were assigned to treatment groups according to their fibrosis stage. Early-stage fibrosis: simeprevir 150 mg, daclatasvir 60 mg, sofosbuvir 400 mg once daily for 6 weeks; compensated cirrhosis: same regimen for 8 weeks. The primary endpoint was sustained virologic response 12 weeks after the end of treatment (SVR12). Safety, tolerability and pharmacokinetics of simeprevir, daclatasvir and sofosbuvir were investigated. Sixty-eight patients were treated (6-week group: n = 59; 8-week group: n = 9). SVR12 was achieved by 86.4% (51/59) of patients with early-stage fibrosis and by 100% (9/9) of patients with cirrhosis. The main reason for not achieving SVR12 in the 6-week group was viral relapse (11.9%; 7/59). One patient had on-treatment failure due to an early withdrawal (lost to follow-up due to incarceration). One patient with SVR12 in the 6-week group had a late viral relapse at post-treatment week 24. No clinically significant drug-drug interactions were observed. Adverse events were reported in 63.2% of patients (43/68) and were mainly grade 1/2. None of these led to treatment discontinuation. The 3 direct-acting antiviral regimens of simeprevir, daclatasvir and sofosbuvir were safe and well tolerated in treatment-naïve, HCV GT1-infected patients with early-stage fibrosis or compensated cirrhosis.

Intrapatient viral diversity and treatment outcome in patients with genotype 3a hepatitis C virus infection on sofosbuvir-containing regimens.

Treatment with the direct-acting antiviral agent (DAA) sofosbuvir (SOF), an NS5B inhibitor, and velpatasvir (VEL), an NS5A inhibitor, demonstrates viral cure rates of ≥95% in hepatitis C virus (HCV) genotypes (GT) 1-6. Here, we investigated intrapatient HCV diversity in NS5A and NS5B using Shannon entropy to examine the relationship between viral diversity and treatment outcome. At baseline, HCV diversity was lowest in patients infected with HCV GT3 as compared to the other GTs, and viral diversity was greater in NS5A than NS5B (P < .0001). Treatment outcome with SOF/VEL or the comparator regimen of SOF with ribavirin (RBV) was not correlated with baseline diversity. However, among persons treated with SOF/VEL, a decrease in diversity from baseline was observed at relapse in the majority virologic failures, consistent with a viral bottleneck event at relapse. In contrast, an increase in diversity was observed in 27% of SOF+RBV virologic failures. We investigated whether the increase in diversity was due to an increase in the transition rate, one mode of potential RBV-mediated mutagenesis; however, we found no evidence of this mechanism. Overall, we did not observe that viral diversity at baseline influenced treatment outcome, but the diversity changes observed at relapse can improve our understanding of RBV viral suppression in vivo.

The frequency of acute kidney injury in patients with chronic hepatitis C virus infection treated with sofosbuvir-based regimens.

BACKGROUND: Guidelines recommend withholding sofosbuvir (SOF) in patients with an estimated glomerular filtration rate (eGFR) of less than 30 mL/min. AIM: To assess the risk of acute kidney injury (AKI) in patients with no renal contraindications for SOF-based treatment. METHODS: This multicenter retrospective observational study included all consecutive patients that were treated with SOF-based or telaprevir/boceprevir (TVR/BOC)-based regimens at two tertiary university centers in North America. AKI was defined as an increase of ≥0.3 mg/dL (≥26.5 µmol/L) in serum creatinine level. Multivariable logistic regression analysis was used to identify risk factors for the occurrence of AKI. RESULTS: In total, 426 patients were included and treated with a SOF-based regimen (n=233, 54.7%) or TVR/BOC-based regimen (n=193, 45.3%). Among patients treated with a TVR/BOC-based regimen 34 (18%) of 193 patients experienced AKI compared to 26 (11%) of 233 patients treated with SOF-based regimens (P=.056). Multivariable logistic regression analysis showed that the presence of ascites (OR: 4.44, 95%CI: 1.46-13.54, P=.009) and the use of NSAIDs (OR: 4.47, 95%CI: 1.32-15.19, P=.016) were associated with a risk of AKI during SOF-based antiviral therapy. Creatinine levels returned to normal at end of follow-up in 23 (88%) of the 26 patients who experienced AKI with a SOF-based regimen and had a creatinine level available during follow-up. CONCLUSIONS: Although the risk for AKI was lower than for patients treated with TVR/BOC-based regimens, AKI was seen during 11% of SOF-based regimens and was mostly reversible. Patients with ascites and patients using NSAIDs have an increased risk for AKI during SOF-based antiviral therapy.

Inducing Hepatitis C Virus Resistance After Pig Liver Transplantation-A Proof of Concept of Liver Graft Modification Using Warm Ex Vivo Perfusion.

Normothermic ex vivo liver perfusion (NEVLP) offers the potential to optimize graft function prior to liver transplantation (LT). Hepatitis C virus (HCV) is dependent on the presence of miRNA(microRNA)-122. Miravirsen, a locked-nucleic acid oligonucleotide, sequesters miR-122 and inhibits HCV replication. The aim of this study was to assess the efficacy of delivering miravirsen during NEVLP to inhibit miR-122 function in a pig LT model. Pig livers were treated with miravirsen during NEVLP or cold storage (CS). Miravirsen absorption, miR-122 sequestration, and miR-122 target gene derepression were determined before and after LT. The effect of miravirsen treatment on HCV infection of hepatoma cells was also assessed. NEVLP improved miravirsen uptake versus CS. Significant miR-122 sequestration and miR-122 target gene derepression were seen with NEVLP but not with CS. In vitro data confirmed miravirsen suppression of HCV replication after established infection and prevented HCV infection with pretreatment of cells, analogous to the pretreatment of grafts in the transplant setting. In conclusion, miravirsen delivery during NEVLP is a potential strategy to prevent HCV reinfection after LT. This is the first large-animal study to provide "proof of concept" for using NEVLP to modify and optimize liver grafts for transplantation.

Time to viral suppression is not related to achievement of SVR12 in HCV GT1-infected patients treated with ombitasvir/paritaprevir/ritonavir and dasabuvir with or without ribavirin.

High rates of sustained virologic response at post-treatment week 12 (SVR12) were achieved in six phase 3 trials of ombitasvir (OBV, an NS5A inhibitor), paritaprevir (an NS3/4A protease inhibitor) co-dosed with ritonavir (PTV/r) + dasabuvir (DSV, an NS5B RNA polymerase inhibitor) (ie, 3D regimen) with or without ribavirin (RBV) in adults with chronic genotype (GT) 1 hepatitis C virus (HCV) infection. We assessed whether time to first HCV RNA value below the lower limit of quantification in patients with and without cirrhosis was associated with achievement of SVR12. Data were analysed from GT1-infected patients enrolled in six phase 3 studies of 3D ± RBV. Patients who experienced non-virologic failure were excluded from analysis. HCV RNA was determined using the Roche COBAS TaqMan RT-PCR assay (lower limit of quantification, LLOQ =25 IU/mL). SVR12 was analysed by week of first HCV RNA suppression, defined as HCV RNA

Combined ursodeoxycholic acid (UDCA) and fenofibrate in primary biliary cholangitis patients with incomplete UDCA response may improve outcomes.

BACKGROUND: Fibrates appear to improve biochemistry in patients with primary biliary cholangitis (PBC), but it is unclear which factors predict response and whether treatment improves transplant-free survival. AIM: To evaluate biochemical profiles, liver-related outcomes and adverse events following fenofibrate therapy in PBC patients with incomplete response to ursodeoxycholic acid (UDCA). METHODS: A retrospective cohort study was performed at a tertiary centre. Cox regression was used to compare outcomes between patients treated with fibrates and UDCA (FF) or UDCA alone, adjusted for a propensity score to account for treatment selection bias. RESULTS: A total of 120 patients were included (FF group n = 46, UDCA group n = 74, median fenofibrate treatment 11 months); 41% vs. 7% met the Toronto criteria for biochemical response [alkaline phosphatase ≤1.67 times the upper limit of normal] in the FF and UDCA groups, respectively (P = 0.0001). Fenofibrate was also associated with improved decompensation-free and transplant-free survival [hazard ratio (HR) 0.09, 95% CI 0.03-0.32, P = 0.0002]. However, only fenofibrate use, not biochemical response, was independently associated with improved outcomes on multivariable analysis (HR 0.40, 95% CI 0.17-0.93, P = 0.03). Twenty-two percent discontinued fenofibrate due to adverse events (most common: abdominal pain and myalgias). In cirrhotic patients, bilirubin increased more rapidly in the FF group (P = 0.005). CONCLUSIONS: Fenofibrate therapy is associated with significant improvement in alkaline phosphatase, decompensation-free and transplant-free survival in PBC patients with incomplete UDCA response. However, fenofibrate should be used cautiously in cirrhosis, with close monitoring for clinical/biochemical decompensation. Additional studies are required to assess the validity of alkaline phosphatase as an appropriate response criteria for fibrate therapy.

Protease inhibitors partially overcome the interferon nonresponse phenotype in patients with chronic hepatitis C.

The outcome of triple therapy with protease inhibitors (PI) depends on the intrinsic response to interferon. Interferon-stimulated gene (ISG) expression differs by cell type in the liver and is a strong predictor of interferon responsiveness. Patients who respond well to interferon have low/absent ISG expression in hepatocytes but significant ISG expression in macrophages. Nonresponders (NRs) show the opposite pattern. We aimed to determine the association between cell-type-specific ISG staining and treatment outcome with PI-based triple therapy. Liver biopsy tissue from consecutive patients treated with boceprevir or telaprevir with peginterferon and ribavirin was stained for myxovirus A (MxA). Staining was scored 0-3 in macrophages (M-MxA) and hepatocytes (H-MxA), and IL28B genotyping was performed. Of 56 patients included 41 achieved SVR (73%) (sustained virological response), 2 (4%) relapsed, 10 (18%) were NRs, and 3 (5%) were lost to follow-up. Median M-MxA staining was stronger and H-MxA staining was weaker in patients who achieved SVR. MxA staining correlated with IL28B genotype and with the HCV RNA decline during lead-in phase. However, unlike with dual therapy, the negative predictive value (NPV) of absent or weak M-MxA staining was poor (42%), while the positive predictive value improved (93%). Although by multivariable logistic regression M-MxA staining was significantly associated with SVR (OR 4.35, 1.32-14.28, P = 0.012), the predictive ability was inadequate to withhold therapy. The interaction between macrophages and hepatocytes plays a critical role in interferon responsiveness; however, the addition of a PI at least partially overcomes the interferon nonresponse phenotype making the predictive ability of ISG staining less clinically useful.

Liver injury is associated with mortality in sickle cell disease.

BACKGROUND: Increased life expectancy in sickle cell disease (SCD) has resulted in greater recognition of the consequences of repeated intravascular vaso-occlusion and chronic haemolysis to multiple organ systems. AIM: To report the long-term consequences of liver dysfunction in SCD. METHODS: A cohort of SCD patients was prospectively evaluated at the National Institutes of Health (NIH) Clinical Center. The association of mortality with liver enzymes, parameters of liver synthetic function and iron overload was evaluated using Cox regression. RESULTS: Exactly, 247 SCD patients were followed up for 30 months of whom 22 (9%) died. After controlling for predictors, increased direct bilirubin (DB), ferritin, alkaline phosphatase and decreased albumin were independently associated with mortality. In a multivariable model, only high DB and ferritin remained significant. Ferritin correlated with hepatic iron content and total blood transfusions but not haemolysis markers. Forty patients underwent liver biopsies and 11 (28%) had fibrosis. Twelve of 26 patients (48%) had portal hypertension by hepatic venous pressure gradient (HVPG) measurements. All patients with advanced liver fibrosis had iron overload; however, most patients (69%) with iron overload were without significant hepatic fibrosis. Ferritin did not correlate with left ventricular dysfunction by echocardiography. DB correlated with bile acid levels suggesting liver pathology. Platelet count and soluble CD14 correlated with HVPG indicating portal hypertension. CONCLUSIONS: Ferritin and direct bilirubin are independently associated with mortality in sickle cell disease. Ferritin likely relates to transfusional iron overload, while direct bilirubin suggests impairment of hepatic function, possibly impairing patients' ability to tolerate systemic insults.

Reduced risk of relapse after long-term nucleos(t)ide analogue consolidation therapy for chronic hepatitis B.

BACKGROUND: Before stopping nucleos(t)ide analogue (NA) treatment in chronic hepatitis B (CHB), 6-12 months of consolidation therapy is recommended. AIM: To investigate the effect of consolidation therapy on off-treatment outcomes in CHB patients. METHODS: We included 94 patients who stopped NA after at least 1 year of therapy. Patients could be HBeAg-positive or HBeAg-negative at start-of-treatment, but were HBeAg-negative and had undetectable HBV DNA at time of discontinuation. Consolidation therapy was defined as treatment after the first undetectable HBV DNA (and HBeAg loss for HBeAg-positive patients) until NA cessation. RESULTS: At 3 years, 74% of the start-of-treatment HBeAg-positive and 75% of the start-of-treatment HBeAg-negative patients developed HBV DNA >2000 IU/mL at a single time point, whereas a persistent virological relapse (≥2 tests of HBV DNA >2000 IU/mL 6 months apart within 1 year) developed in 49% of the start-of-treatment HBeAg-positive and 53% of the start-of-treatment HBeAg-negative patients. For both HBeAg-positive and HBeAg-negative patients, consolidation therapy of ≥3 years was associated with lower persistent virological relapse rates compared to <1 year (1-year relapse rate: 25% vs. 54%; P = 0.063 and 24% vs. 57%; P = 0.036, respectively). At 3 years, 9% of the HBeAg-positive and 14% of the HBeAg-negative patients became HBsAg-negative. Prolonged consolidation therapy increased the likelihood of HBsAg loss. Two cirrhotic patients developed hepatic decompensation but both recovered. CONCLUSIONS: After nucleos(t)ide analogue discontinuation, relapse was common in patients with chronic hepatitis B. Prolongation of consolidation therapy beyond 3 years decreased the risk of persistent virological relapse and increased the likelihood of HBsAg loss.

Hepatitis B reactivation in HBsAg-negative/HBcAb-positive patients receiving rituximab for lymphoma: a meta-analysis.

Patients with chronic hepatitis B (HBsAg-positive) are at risk of viral reactivation if rituximab is administered without antiviral treatment, a potentially fatal complication of treatment. Patients with so-called 'resolved hepatitis B virus infection' (HBsAg-negative/cAb-positive) may also be at risk. We performed a systematic review of the English and Chinese language literature to estimate the risk of hepatitis B virus (HBV) reactivation in HBsAg-negative/cAb-positive patients receiving rituximab for lymphoma. A pooled risk estimate was calculated for HBV reactivation. The impact of HBsAb status and study design on reactivation rates was explored. Data from 578 patients in 15 studies were included. 'Clinical HBV reactivation', (ALT >3 × normal and either an increase in HBV DNA from baseline or HBsAg seroreversion), was estimated at 6.3% (I(2) = 63%, P = 0.006). Significant heterogeneity was detected. Reactivation rates were higher in prospective vs retrospective studies (14.2% vs 3.8%; OR = 4.39, 95% CI 0.83-23.28). Exploratory analyses found no effect of HBsAb status on reactivation risk (OR = 0.083; P = 0.151). Our meta-analysis confirms a measurable and potentially substantial risk of HBV reactivation in HBsAg-negative/cAb-positive patients exposed to rituximab. However, heterogeneity in the existing literature limits the generalizability of our findings. Large, prospective studies, with uniform definitions of HBV reactivation, are needed to clarify the risk of HBV reactivation in HBsAg-negative/cAb-positive patients.

The number needed to treat to prevent mortality and cirrhosis-related complications among patients with cirrhosis and HCV genotype 1 infection.

Cirrhotic patients with chronic hepatitis C virus (HCV) infection remain at risk for complications following sustained virological response (SVR). Therefore, we aimed to evaluate treatment efficacy with the number needed to treat (NNT) to prevent clinical endpoints. Mortality and cirrhosis-related morbidity were assessed in an international multicentre cohort of consecutively treated patients with HCV genotype 1 infection and cirrhosis. The NNT to prevent death or clinical disease progression (any cirrhosis-related event or death) in one patient was determined with the adjusted (event-free) survival among patients without SVR and adjusted hazard ratio of SVR. Overall, 248 patients were followed for a median of 8.3 (IQR 6.2-11.1) years. Fifty-nine (24%) patients attained SVR. Among patients without SVR, the adjusted 5-year survival and event-free survival were 94.4% and 80.0%, respectively. SVR was associated with reduced all-cause mortality (HR 0.15, 95% CI 0.05-0.48, P = 0.002) and clinical disease progression (HR 0.16, 95% CI 0.07-0.36, P < 0.001). The NNT to prevent one death in 5 years declined from 1052 (95% CI 937-1755) at 2% SVR (interferon monotherapy) to 61 (95% CI 54-101) at 35% SVR (peginterferon and ribavirin). At 50% SVR, which might be expected with triple therapy, the estimated NNT was 43 (95% CI 38-71). The NNT to prevent clinical disease progression in one patient in 5 years was 302 (95% CI 271-407), 18 (95% CI 16-24) and 13 (95% CI 11-17) at 2%, 35% and 50% SVR, respectively. In conclusion, the NNT to prevent clinical endpoints among cirrhotic patients with HCV genotype 1 has declined enormously with the improvement of antiviral therapy.

Long-term outcome of chronic hepatitis C after sustained virological response to interferon-based therapy.

BACKGROUND: Although the short-term benefits of a sustained virological response (SVR) to interferon-based therapies of chronic hepatitis C (CHC) are well known, the long-term consequences of SVR are less clear. AIM: To assess changes in markers of disease activity and fibrosis in patients followed up to 23 years post-SVR. METHODS: The first 103 SVR patients (from 1984 to 2003) at the National Institutes of Health Clinical Center were evaluated. Serum markers before treatment and at the last visit were compared. Evaluations after 2007 included transient elastography (TE). RESULTS: Of 103 patients, three subsequently relapsed 0.7, 6.3 and 6.5 years post therapy. The remaining 100 patients (56 men, mean age 56 years) maintained SVR at final follow-up. No patients developed hepatic decompensation, but one with pre-treatment cirrhosis died 12 years post SVR of hepatocellular carcinoma. In comparison to pre-treatment values, markers improved at follow-up, including mean ALT (152-27 U/L), AST (87-24 U/L), alkaline phosphatase (78-69 U/L), IgG (1463-1113 mg/dL), platelet count (209 000-239 000/µL) and AST to platelet count ratio index (APRI: 1.31-0.33). TE was performed in 69 patients and was normal (<7.0 kPA) in 60%, moderately elevated (7.1-13.8) in 31% and cirrhotic range (>13.8) in 9%. TE and platelet counts at follow-up correlated with fibrosis on pre-treatment liver biopsy (P < 0.001). CONCLUSIONS: In 97% of patients with CHC, SVR is durable without evidence of disease progression, although some degree of hepatic fibrosis may persist and patients with pre-treatment cirrhosis are at continuing low risk for hepatocellular carcinoma.

Randomised clinical trial: the benefit of combination therapy with adefovir and lamivudine for chronic hepatitis B.

BACKGROUND: Combination antiviral therapy holds the promise of increasing response rates while decreasing antiviral resistance, but has yet to be shown to be beneficial or necessary in chronic hepatitis B. AIM: To evaluate the benefit of combination therapy with adefovir and lamivudine versus adefovir alone in maintaining virological, biochemical and histological responses. METHODS: Patients with chronic hepatitis B with and without previous lamivudine therapy were randomised to receive adefovir alone (10 mg/daily) or adefovir and lamivudine (100 mg/daily) for up to 192 weeks. Study endpoints were (i) maintained virological (HBV DNA <500 copies/mL), biochemical and histological response, (ii) loss of HBeAg and (iii) loss of HBsAg. RESULTS: A total of 41 patients were enrolled, including 31 HBeAg -positive and 31 treatment-naïve subjects. 30 patients remained on assigned therapy at 192 weeks. The percentage of patients achieving a combined maintained response was higher in the combination than the monotherapy arm, both at week 48 (59% vs. 26%, P = 0.06) and 192 (68% vs. 31%, P = 0.03). At week 192, 76% of the combination vs. 36% of the monotherapy group had loss of HBeAg (P = 0.03). One patient receiving adefovir cleared HBsAg. Adefovir resistance developed in 6 of 19 (32%) monotherapy but none of 22 combination treated patients (P = 0.03). CONCLUSIONS: Extended combination therapy with lamivudine and adefovir is associated with a high rate of long-term virological and biochemical response. Adefovir monotherapy appears to be less effective mainly because of poor initial response and the ultimate development of antiviral resistance (www.Clinical. Trials.gov NCT00023309).

Low- and standard-dose peginterferon alfa-2a for chronic hepatitis C, genotype 2 or 3: efficacy, tolerability, viral kinetics and cytokine response.

BACKGROUND: Chronic infection with hepatitis C, genotype 2/3, responds better than other genotypes to peginterferon and ribavirin treatment. We hypothesized that a lower dose of peginterferon would be as effective, but less toxic than standard doses. AIM: To test the hypothesis that a lower dose of peginterferon would be as effective as, but less toxic than, standard doses. METHODS: A total of 30 patients were treated with low-dose peginterferon alfa-2a (90 microg/week) and 27 patients with standard doses (180 microg/week) for 24 weeks in combination with 800 mg/day of ribavirin. Patients who failed treatment were offered 48 weeks of standard-dose treatment. Viral and serum inducible protein 10 (IP-10) levels were measured and early viral kinetic parameters were calculated. RESULTS: Sustained virological response was achieved in 68% of the low-dose and 87% of the standard-dose patients (per protocol, P = 0.79 for non-inferiority). Re-treatment was successful in all patients who tolerated full dose and duration. The standard-dose group had greater first-phase declines of viral levels and faster time to negativity. The second-phase slope was not dose-dependent. IP-10 induction was significantly greater with the standard dose. Although fatigue and general feeling during treatment were worse for standard dose, haematological toxicity and depression did not differ between groups. CONCLUSION: A lower dose of peginterferon is associated with some symptomatic benefit, but the response is not equivalent to standard dosing.