The incidence of chronic hepatitis C virus (HCV) infection is rather high. Its most frequent consequences are chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma.

In treatment of chronic HCV infection, interferons have antiviral, anriproliferative, and immunoregulatory action. Within the cell, they induce protein synthesis, inhibiting viral replication. The most important among them are RNA dependent protein kinase, and eukaryotic initiation factor. However, viral proteins prevent their phosphorylation and activation. In order to overcome this problem, treatment is prolonged, higher doses of lFN are used, as well as induction therapy. The optimal period for viral response is 52 weeks, while induction therapy has shown controversial results.

The most relevant randomized controlled trials of interferon-alpha (IFN) for naive patients with chronic hepatitis C (CHC) published in a decade, just before appearance of pegylated IFN trials in 2000, were included in this paper. Its purpose is to review the relationship between sustained biochemical response in active versus control group versus usual clinical variables as IFN regimens, cirrhosis, genotype and versus less frequently addressed variables as funding, methodological quality or location of principal author. Meta-analysis estimates of global treatment effect varied according to trial design: group 1=IFN versus placebo/no treatment, 32 RCTs, 2499 pts, OR 9.5 (6.3-14.2); group 2a=comparison of IFN schedules, 43 RCTs, 7454 pts, OR 1.6 (1.4-1.9); group 2b=IFN+other drugs versus standard IFN, 30 RCTs, 4737 pts, OR 2.0 (1.6-2.6). Fixed effects (arm-level) meta-regression on the complete data set (171 arms, 10,580 pts) revealed that sustained response was most likely in experimental arms of IFN+ribavirin or other drugs (OR 2.4), arms using yearly schedule (OR 2.0), trial principal author from Asia (OR 1.7), trial sample size >200 (OR 1.4) and arms enrolling less than 50% of cirrhotics (OR 1.3). Moreover, focus was on some significant interactions too, as the effect of trial's quality interacting to the recorded funding (more benefit if no-profit, less if for-profit) and the effect of trial funding interacting to the location of first author (more benefit if from Asia). Three main effects (experimental arm, cirrhosis, funding) and one interaction (funding*location of principal author) explained 31% of between study variability in a random-effect meta-regression. In a subgroup analysis on a data set including available information on HCV genotype (93 arms, around 7000 pts), meta-regression revealed that genotype 1 or 4 less than 50% per arm and specialistic journal were significant predictors of either biochemical (transaminases) or virological (HCV-RNA) sustained response, in a model including the same main effects identified in the complete data set analysis. Finally, although mostly captured by different IFN regimens along time, heterogeneity of effect in a large set of (not-pegylated) IFN trials was also explained by HCV genotype and variables of quality and reporting, such as trial's principal author from Asia.

Today medical-scientific data are diluted by the marketing strategies of the biomedical industry making it difficult for practising physicians to decide what is correct or wrong. One typical example is the use of pegylated interferons for treatment of chronic hepatititis C. In this report the arguments pro and contra weight-based dosing are critically discussed. The factors contributing to success or failure to eradicate the virus are manifold, and include the sensitivity of the virus to interferon, viral genotype, age, gender stage of fibrosis, presence or absense of steatosis. Weight by itself plays just a minor role. The impact of weight-based dosing in general is overestimated and certainly not needed when 40 kD branched PEG-IFNalpha2a with a restricted volume of distribution is used. Whether weight-based dosing of 12 kD linear PEG-IFNalpha2b provides any benefit over a flat dose of the drug remains to be studied.

Conventional interferon monotherapy fails to achieve virological clearance in most hepatitis C-infected patients. The use of high-dose induction regimens may improve the initial clearance of virus, while the addition of ribavirin appears to improve the rates of sustained response once clearance is achieved.

To compare the efficacy and safety of re-treatment with an induction regimen of high-dose interferon alpha-2b, with or without ribavirin, in chronic hepatitis C patients who have not responded to standard dose interferon monotherapy.

Previous virological non-responders to standard dose interferon (3-5 MU three times weekly for > or = 12 weeks) were randomized to receive, unblind, either 10 MU interferon alpha-2b daily for 10 days, then 5 MU daily for 74 days, then 5 MU three times weekly for 24 weeks (total 36 weeks) (group A), or the above regimen with the addition of ribavirin, 1000-1200 mg/day, at day 11 (group B). All patients were followed up for 24 weeks after completion of therapy.

End of treatment virological response was noted in one of 10 (10%) patients in group A and in eight of 15 (54%) patients in group B (P=0.04). The sole end treatment responder in group A and three in group B relapsed on follow-up. The apparent improvement in response in group B compared to group A nearly reached statistical significance (group B 5/15 vs. group A 0/10; P=0.06).

In this small pilot study, a 36-week high-dose induction interferon monotherapy protocol did not yield sustained responses in previous non-responders to standard dose interferon. However, the same regimen with ribavirin yielded a 33% sustained response rate, nearly reaching statistical significance. The therapy was well tolerated, despite the higher doses of interferon used and the addition of ribavirin. High-dose interferon with ribavirin appears to be a therapeutic option for non-responders to conventional interferon monotherapy.

A previous meta-analysis of interferon therapy in naive patients with chronic hepatitis C has documented its efficacy in achieving virologic clearance, and improving liver biochemistry and histology; however, since its publication additional trials have been reported.

To evaluate the response to interferon in interferon naive patients with chronic hepatitis C. The effect of treatment dose and duration, and the response in patients with cirrhosis and those with normal aminotransferases was also investigated.

The Cochrane Controlled Trials Register (Cochrane Library Issue 1, 1999), MEDLINE (January 1966 to December 1999), and reference lists were searched, and pharmaceutical companies were contacted for unpublished trials.

Randomised clinical trials comparing interferon with placebo, no treatment, or different regimens of interferon were selected. Abstracts were excluded.

The primary outcome measure was sustained disappearance of serum HCV RNA (virologic sustained response (SR)). Biochemical and end of treatment responses, liver histology, and adverse events were also recorded. Assessment of drug efficacy used the methods of Peto and Der Simonian and Laird.

Fifty-four trials enrolling 6545 patients were included. Compared with no treatment, interferon 3 MU thrice weekly for 12 months increased the probability of a virologic SR (Peto odds ratio (OR) 4.60; 95% confidence interval (CI) 1.53 to 13.85). At this dosage and duration of therapy, the rate of virologic SR was 17% (95% CI 10 to 28%) in interferon-treated patients versus 3% (95% CI 1 to 10%) in controls. A dose of 6 MU was more effective than 3 MU thrice weekly (OR for 12 months treatment, 2.21; 95% CI 1.10 to 4.45), as were durations of 12 months or greater versus six months (OR 1.87; 95% CI 1.30 to 2.67). Adverse events were more common with higher doses and prolonged durations of treatment. Compared with no therapy, interferon increased the probability of histologic improvement (OR 9.22; 95% CI 5.69 to 14.94). The response to interferon in cirrhotic patients (virologic SR, 17%; 95% CI 11 to 26%) was similar to that in non-cirrhotic patients. However, interferon was no more effective than control in patients with normal aminotransferases.

Interferon is effective in achieving viral clearance and improving liver biochemistry and histology in interferon naive patients with chronic hepatitis C. Higher doses and prolonged durations are more effective, but associated with more frequent adverse events. Interferon is associated with similar benefits in patients with cirrhosis, but the efficacy in patients with normal aminotransferases is unproven.

Despite improvements in the therapies for chronic hepatitis C virus (HCV) over the past several years, many patients still fail to become hepatitis C virus ribonucleic acid (HCV-RNA) undetectable during treatment and are classified as nonresponders. Providing treatment recommendations for these patients requires that the likelihood of achieving any benefit from another course of therapy be balanced with the natural history of chronic HCV. The management of nonresponders represents the most challenging of all aspects in the care of patients with chronic HCV. Retreatment of interferon non-responders with interferon and ribavirin has yielded a long-term virologic benefit in only 10% to 25% of patients. The efficacy of peginterferon and peginterferon with ribavirin for nonresponders has yet to be defined.

The primary therapy for patients with chronic hepatitis C virus (HCV) infection is interferon alfa. However, use of interferon for treatment of chronic HCV has several shortcomings that limit its effectiveness. Interferon has a very short half-life, must be administered multiple times weekly, and is associated with significant side effects. "PEGylation" is a process whereby the inert polymer, polyethylene glycol (PEG), is attached to a protein pharmaceutical. This process has been shown to alter the properties of PEGylated proteins in a manner that significantly extends half-life, reduces immunogenicity, and enhances biologic activity when compared with the native protein. In recent years, several PEGylated forms of interferon alfa have been developed. Recent studies have demonstrated that PEG-interferons have a significantly prolonged half-life and sustained virologic response when compared with standard interferon. Studies to evaluate the effects of combining PEG-interferons with ribavirin are currently underway. The role PEG-interferons will play in patients who have either relapsed or failed to respond to previous interferon or interferon/ribavirin therapy remains to be defined.

To review the literature on the treatment of chronic hepatitis C virus (HCV) infection.

MEDLINE search (1986-December 1999) using key words such as HCV, hepatitis, non-A and non-B hepatitis, as well as terms regarding treatment during that time period.

HCV infection was initially treated with interferon monotherapy, but only a minority of patients responded to long-term therapy. A higher rate of response in both interferon-naïve patients and interferon-relapsers has been achieved by using the combination of interferon and ribavarin. Other treatment regimens including high-dose interferon protocols, ursodeoxycholic acid, amantadine, and nonsteroidal antiinflammatory drugs have been less promising. Many alternative therapies are being investigated.

HCV infection is a major public health problem. It is now possible to achieve a cure in nearly 50% of the patients with this infection. Many additional therapies are being evaluated in order to achieve a higher cure rate.

: At least half of patients with chronic hepatitis C virus (HCV) fail to respond to interferon or interferon/ribavirin therapy. Histological improvement is observed in some nonresponders. We conducted a randomized, controlled trial to determine if maintenance interferon therapy could prevent histological progression in this subset of nonresponders.

Fifty-three patients with chronic HCV were enrolled. All were HCV-RNA positive after 6 months of treatment with interferon alfa-2b but had a histological response. Twenty-seven of the patients were randomly assigned to continue interferon (3 MU 3 times weekly) for 24 months; 26 patients discontinued treatment and were observed prospectively. Alanine aminotransferase (ALT) level and HCV-RNA titer were monitored, and liver biopsy was repeated every 12 months.

Before interferon therapy, the 2 groups were well matched for all demographic factors, serum ALT (94.0 +/- 15.6), log HCV-RNA titer (5. 85 +/- 0.15 copies/mL), histology score (9.5 +/- 0.2), and percentage with cirrhosis (25%). After 6 months of treatment, significant reductions (P < 0.05) in serum ALT level (62.6 +/- 9.6), log HCV-RNA titer (4.79 +/- 0.13 copies/mL), and hepatic inflammation (4.0 +/- 0.2) were observed. These improvements were maintained in the patients randomized to continue interferon. Stopping treatment was associated with an increase in serum ALT, log HCV-RNA, and hepatic inflammation back to baseline. After 30 months of treatment, mean fibrosis score declined from 2.5 to 1.7 and 80% of patients had histological improvement (P < 0.03). Discontinuation of interferon was associated with an increase in mean fibrosis score from 2.2 to 2.4 and worsening of hepatic histology in 30% of patients (P < 0.01).

These data support the hypothesis that maintenance interferon may prevent histological progression of chronic HCV in patients who remain viremic.

Interferon alfa is the only effective treatment for patients with chronic hepatitis C. Forty percent of patients have an initial response to this therapy, but most subsequently relapse. We compared the effect of interferon alone with that of interferon plus oral ribavirin for relapses of chronic hepatitis C.

We studied 345 patients with chronic hepatitis C who relapsed after interferon treatment. A total of 173 patients were randomly assigned to receive standard-dose recombinant interferon alfa-2b concurrently with ribavirin (1000 to 1200 mg orally per day, depending on body weight) for six months, and 172 patients were assigned to receive interferon and placebo.

At the completion of treatment, serum levels of hepatitis C virus (HCV) RNA were undetectable in 141 of the 173 patients who were treated with interferon and ribavirin and in 80 of the 172 patients who were treated with interferon alone (82 percent vs. 47 percent, P<0.001). Serum HCV RNA levels remained undetectable 24 weeks after the end of treatment in 84 patients (49 percent) in the combination-therapy group, but in only 8 patients (5 percent) in the interferon group (P<0.001). Sustained normalization of serum alanine aminotransferase concentrations and histologic improvement were highly correlated with virologic response. Base-line serum HCV RNA levels of 2 x 10(6) copies per milliliter or less were associated with higher rates of response in both treatment groups. Viral genotypes other than type 1 were associated with sustained responses only in the combination-therapy group. Combined therapy caused a predictable fall in hemoglobin concentrations but otherwise had a safety profile similar to that of interferon alone.

In patients with chronic hepatitis C who relapse after treatment with interferon, therapy with interferon and oral ribavirin results in higher rates of sustained virologic, biochemical, and histologic response than treatment with interferon alone.

Clinical recurrence of hepatitis C after liver transplantation can lead to cirrhosis, liver failure, and death. In patients undergoing liver transplantation for hepatitis C, we assessed the efficacy of interferon alfa-2b (IFN) in preventing recurrent hepatitis. We randomized 86 patients to either an IFN group (3 MU three times a week starting within 2 weeks after transplantation and continued for 1 year) or a control (no IFN) group. Recurrence, the primary end point, was diagnosed on biopsy performed at 1 year or for abnormal biochemistries. HCV RNA levels were measured by branched-chain DNA (bcDNA) assay and arbitrarily defined as low, moderate, or high (< 10 x 10(5), 10-100 x 10(5), or > 100 x 10(5) Eq/mL, respectively). Data on 30 IFN patients and 41 no-IFN patients who survived > or = 3 months were reviewed. Mean follow-up was 669 +/- 228 days for IFN patients and 594 +/- 254 days for no-IFN patients. IFN patients were less likely to develop recurrent hepatitis (8 IFN vs. 22 no-IFN patients, P = .017, log rank analysis). IFN and 1-month HCV RNA level were independent predictors of recurrence. IFN reduced the risk of recurrence by a factor of 0.4 (P = .04, Cox proportional hazards model); HCV RNA level > 100 x 10(5) Eq/mL at 1 month after transplantation increased the risk by a factor of 3.1 (P = .01). Low, moderate, and high viral levels at 1 and 3 months were associated with significantly different rates of recurrence in IFN patients (P = .05 at 1 month and P = .003 at 3 months) but not in untreated patients (P = .28 at 1 month and P = .25 at 3 months). In patients with two or more rejections, the risk of recurrence was increased by a factor of 2.17 (P = .05). On 47 1-year biopsies (24 IFN; 23 no IFN), piecemeal necrosis was more common in untreated patients (P < .02). One- and 2-year patient survival, respectively, was 96% and 96% with IFN and 91.2% and 87.2% without (P = NS). Prophylactic IFN reduced the incidence of recurrent hepatitis after transplant. Although IFN was most effective in patients with low HCV RNA levels, we also noted an effect in patients with moderate levels. IFN did not prevent viremia, suggesting that it may work through alternative mechanisms.

The influence of different anticoagulants and pre-amplification storage conditions on the stability of hepatitis C virus (HCV)-RNA, as detected by the quantitative HCV NASBA assay (NASBA-QT), was studied. The HCV-RNA load remained stable for at least 15 months when serum or plasma samples (EDTA and heparin) were directly frozen at -70 degrees C in lysis buffer. At 4 degrees C, the HCV-RNA load in serum or plasma stored with lysis buffer did not decline for at least 14 days. At 30 degrees C, however, the load declined significantly after 7 days. When clotted, whole blood was stored at 4 degrees C, the HCV-RNA load was stable for 72 h. However, when EDTA-anticoagulated whole blood was stored at 4 degrees C, the HCV-RNA load declined significantly after 48 h. In paired plasma and serum samples at baseline the HCV-RNA levels were similar. Heparin did not influence the efficiency of the HCV NASBA-QT assay. Clotted blood as well as EDTA or heparin anticoagulated blood can be used for quantifying HCV-RNA using the NASBA-QT assay. Blood samples should be stored at 4 degrees C after collection and serum or plasma separated within 24 h. Preferably, after separation, samples should be frozen in lysis buffer at -70 degrees C until NASBA-QT analysis.

In an attempt to improve the limited efficacy of treatment of chronic hepatitis C with interferon-alpha 3 MU tiw, we studied the effects of double-dose therapy followed by downward titration, and analyzed the pre- and pertreatment factors associated with response or non-response.

Three hundred and fifty-four consecutive patients in 19 centers were randomized to interferon-alpha 3 MU tiw for 6 months or 6 MU tiw for 8 weeks followed by down-titration (3,1 MU tiw) till alanine aminotransferase remained normal and plasma HCV RNA was repeatedly undetectable. The primary outcome measure was sustained alanine aminotransferase and HCV RNA response 6 months after treatment.

Three hundred and thirty-six patients received treatment. The sustained response rate for patients receiving 3 MU tiw for 6 months was 14% (9-21%,) and for patients receiving double dose tiw for 8 weeks and thereafter titrated therapy 15% (10-21%) (p=0.8). Pretreatment factors associated with a sustained alanine aminotransferase plus HCV RNA response were the absence of cirrhosis, presence of genotype 2 or 3, a low viral load and, in addition, a low alanine aminotransferase/aspartate aminotransferase ratio; a model was developed to allow estimation of the chance of response for the individual patient. The most powerful predictor of sustained response, however, was plasma HCV RNA at week 4; a positive test virtually precluded a sustained response (1.7%, 0.4-5.0%). If week 4 HCV RNA was not detectable, the chance of a sustained response was 21% (12-34%) for genotype 1 versus 40% (28-54%) for the others (p=0.02). Six MU tiw led to a significantly higher week 4 HCV RNA response (47% not detectable) than 3 MU (37%) (p=0.02). During down-titration this difference in viral on-treatment response was lost.

In the treatment of hepatitis C, an early HCV RNA response is a prerequisite for long-term efficacy. Doubling the initial interferon dose increases this early response, but subsequent downward titration negates this effect, especially in genotype 1.

Hepatitis C is a major cause of liver disease leading to cirrhosis. Although interferon (IFN) is the only approved therapy, treatment is characterized by low response rates and dose-limiting side effects. We evaluated the addition of thymosin alpha1 (TA1), an immunomodulatory peptide, to the standard treatment regimen for hepatitis C to determine if combination therapy shows biological activity using outcome measures including normalization of alanine aminotransferase levels, histological activity, and viral load during treatment. We performed a randomized, double-blind, placebo-controlled trial to compare the biological activity of a combination TA1 and IFN with that seen for IFN alone in patients with chronic hepatitis C infection. One hundred nine patients were randomized for intention to treat and received 1.6 mg of TA1 subcutaneously twice weekly and 3 MU of IFN three times weekly; 3 MU of IFN three times weekly and placebo TA1; or placebo for both agents. All patients had chronic HCV infection with confirmation of chronic hepatitis on liver biopsy. Biochemical responders were followed up until alanine aminotransferase (ALT) levels became abnormal or for 26 weeks, and relapsers were retreated for 26 weeks in the same treatment arm. One hundred three patients completed treatment for 26 weeks, and six patients dropped out. The groups were similar with regard to sex, gender distribution, baseline histological activity index (HAI) score, risk factors, and viral titers. End-of-treatment biochemical response was seen in 37.1% of patients treated with combination therapy, 16.2% of patients treated with IFN alone, and 2.7% of untreated controls by intent-to-treat analysis (IFN/TA1 vs. IFN, chi2 = 4.05, P = .04). HCV RNA clearance was seen in 37.1% of IFN/TA1-treated patients and 18.9% of IFN-treated subjects. Mean HCV RNA titers were significantly lower than baseline at weeks 8, 16, and 24 after drug initiation among patients treated with IFN/TA1 but not in the other treatment arms. Histological improvement, as evidenced by a decrease in HAI of more than two points, occurred in the combination therapy arm more frequently than in comparison groups. Cumulative sustained biochemical responses were 14.2% and 8.1% in the IFN/TA1 and IFN arms, respectively, based on an intention-to-treat model. The combination of TA1 and standard IFN treatment for chronic hepatitis C showed evidence of biological activity at the completion of treatment by biochemical, histological, and virological outcome measures. Further research involving longer duration and varied dosing is needed.

We have evaluated the effect of granulocyte macrophage colony-stimulating factor (GM-CSF) when utilized either alone or in combination with interferon for treatment of chronic hepatitis C virus (HCV).

A total of 71 patients with chronic HCV, elevated alanine aminotransferase and normal hepatic function were enrolled into these studies. Nineteen patients who had previously failed to achieve both biochemical and virologic response during interferon therapy were treated with increasing doses of GM-CSF alone (65-250 microg/m2 three times weekly) for 6 months. Another 52 patients who had not been previously treated with interferon entered a randomized controlled trial; 25 were treated with interferon alone (3 mU three times weekly) and 27 with a combination of interferon+GM-CSF (3 mU+250 microg/m2 three times weekly). All patients were treated for 6 months. Both groups were well matched for age, sex, race, serum alanine aminotransferase, HCV-RNA titer, liver histology score and cirrhosis.

None of the patients treated with GM-CSF alone developed either biochemical or virologic response at any of the treatment dosages and mean HCV-RNA titer remained unchanged from baseline during this therapy. For patients in the randomized controlled trial, biochemical and virologic responses were observed in 54% of interferon-treated patients compared to 31.8% for those treated with interferon+GM-CSF. Long-term sustained virologic response was observed in only one patient in each group. No significant differences were observed in HCV-RNA titer during the course of treatment. GM-CSF treatment was associated with a significant increase in total white blood cell count and absolute eosinophil count, which peaked within the first month of therapy and declined spontaneously during the remaining 5 months.

GM-CSF either alone or in combination with interferon does not appear to be effective for treatment of chronic HCV.

We assessed the long-term effect of a course of interferon therapy on the biochemical and virological markers of Canadian patients with chronic hepatitis C.

Thirty-six patients with chronic hepatitis C were treated with a median total dose of interferon-alpha-2B of 181.0 million U (range 109.0-384.0 million U) and were followed for a median of 37.2 months (range 12.0-94.2 months) after completing treatment. All patients received an initial 16 wk of interferon at a dose of 3 million U three times weekly; this was followed by either no further interferon or by 8 wk more at doses ranging from 1.5 to 10.0 million U three times weekly. Serum alanine aminotransferase (ALT) and hepatitis C virus (HCV) RNA levels were measured before interferon therapy, 6 months after treatment, and at the end of follow-up for each patient. HCV RNA was analyzed by branched DNA 1.0 assay and, if undetectable, by polymerase chain reaction. HCV genotyping was performed on serum samples.

Five (13.6%) of the 36 patients had a sustained treatment response, defined as normal ALT and undetectable viremia 6 months after treatment. All five patients remained in serological remission to the end of their follow-up, a median of 48.2 months (range 23.0-66.2 months) after interferon therapy. Responders were similar to nonresponders in age, gender, initial ALT and serum HCV RNA levels, pretreatment histology, and total dose of interferon received.

In patients with chronic hepatitis C, 13.6% had normal ALT and undetectable serum HCV RNA 6 months after finishing interferon therapy. These patients remained in serological remission to the end of their follow-up, 48.2 months after interferon therapy.

To examine the effect of prolonged treatment with different doses of interferon alpha-2b on the relapse rate in patients with chronic hepatitis C.

One hundred and seventy-one patients with non-cirrhotic chronic hepatitis C were enrolled in an Italian multicenter trial. All patients were treated for 3 months with 3,000,000 Units (3 MU) of interferon alpha-2b given subcutaneously three times a week (t.i.w.). Patients with abnormal alanine aminotransferase (ALT) values were given 6 MU of interferon for an additional 3 months. If ALT remained persistently abnormal, therapy was then suspended. If ALT levels were normal, therapy was continued (6 MU t.i.w.) for an additional 18 months (total=2 years). Patients with normal ALT were randomly assigned to two groups, one receiving 3 MU and the other receiving 6 MU t.i.w. for an additional 21 months (total=2 years). Follow-up continued for 2 years after therapy withdrawal.

Seven patients stopped treatment during the first 3 months. Of the remaining 164 patients, 76 (46%) showed abnormal ALT levels after 3 months of therapy: 11 of these (14%) normalized ALT values when given 6 MU and a sustained response was maintained in eight during the follow-up. Overall, 54 and 34 patients were allocated respectively to the groups receiving the 3 MU and 6 MU long-term treatment. At the end of therapy, 35/54 patients of the group 3 MU and 21/34 patients of the group 6 MU showed normal ALT levels (65% vs 62%, p=N.S.). After 2 years of follow-up, 24/35 (69%) patients of the group 3 MU and 16/21 (76%) of the group 6 MU were still in remission (p=N.S.). In an intention-to-treat analysis, 48/171 (28%) patients showed a long-term response (normal ALT values, HCV-RNA negative). About 65% of the sustained responders showed low baseline viremia compared with 33% of non-responders (p=0.005) while genotype 1b was more frequently found among non-responders than in long-term responders (84% vs 25%, p=0.0001).

About 14% of patients who do not respond to a 3-month course of 3 MU of interferon normalize ALT levels when given 6 MU. In prolonged treatment, there is no significant difference between 3 and 6 MU in inducing a sustained response. Patients with low baseline viremia and genotype 2a respond significantly better to prolonged interferon therapy than highly viremic patients with genotype 1b.