Hepatitis B reactivation during cancer chemotherapy: an international survey of the membership of the American Association for the Study of Liver Diseases.

Hepatitis B virus reactivation (HBVr) can be a serious complication of cancer chemotherapy. However, underutilization of HBV screening and secondary underutilization of antiviral prophylaxis have been frequently reported. The authors electronically distributed a 30-point questionnaire to members of the American Association for the Study of Liver Diseases to capture experiences with HBVr during cancer chemotherapy. The questionnaire specified diagnostic criteria and collected information on HBV screening, antiviral prophylaxis and clinical outcomes. Ninety-nine respondents reported 188 patients who met the criteria for HBV reactivation. Forty-one practised outside the United States, and most were hepatologists (n = 71) or gastroenterologists (n = 12). One hundred and twenty-six patients had haematologic malignancies, of which 88 (70%) had lymphoma. Seventy-five patients (40%) had screening for both hepatitis B surface antigen (HBsAg) and antibody to hepatitis B core antigen (anti-HBc), and an additional 24 patients (13%) had HBsAg screening alone. Prophylactic antiviral therapy was reported in only 18 patients (10%). Chemotherapy was interrupted in 52 patients (41%) with haematologic malignancies and 26 of 41 patients (63%) with solid tumours (P = 0.01). Rituximab-treated patients (n = 66) required hospitalization more frequently (P = 0.04), but their overall survival did not differ from individuals not treated with rituximab. Death due to liver failure was reported in 43 patients overall (23%). Underutilization of prophylactic antiviral therapy occured in a substantial number of patients who were found to be HBV infected prior to the initiation of cancer chemotherapy. The reasons for this need further exploration because reactivation results in serious yet preventable outcomes.

Metformin in the treatment of non-alcoholic steatohepatitis: a pilot open label trial.

BACKGROUND: Insulin sensitizing agents may be useful in treatment of non-alcoholic fatty liver disease. AIM: A pilot study to evaluate the efficacy and safety of metformin in non-alcoholic fatty liver disease. METHODS: In an open labelled study, patients with histologically confirmed non-alcoholic fatty liver disease were given metformin (20 mg/kg) for 1 year. Insulin resistance (by log homeostasis assessment model analysis for insulin resistance and Quantitative Insulin Sensitivity Check Index) and post-treatment hepatic histology were compared with pre-treatment histology. RESULTS: Fifteen patients completed 1 year of treatment. During the initial 3 months, there was improvement in alanine aminotransferase and aspartate aminotransferase (P-value 0.01 and 0.02, respectively) along with improvement in insulin sensitivity. However, after 3 months, there was no further improvement in insulin sensitivity and there was gradual rise in aspartate aminotransferase and alanine aminotransferase back to pre-treatment levels. Among the 10 patients with post-treatment biopsy, three (33%), showed improvement in steatosis, two (20%) showed improvement in inflammation score and one (10%) showed improvement in fibrosis. CONCLUSION: Metformin treatment was associated with only a transient improvement in liver chemistries. A progressive, sustainable reduction in insulin sensitivity was not noted during treatment.

Serum alanine aminotransferase flares during interferon treatment of chronic hepatitis B: is sustained clearance of HBV DNA dependent on levels of pretreatment viremia?

During interferon treatment of chronic hepatitis B, an alanine aminotransferase (ALT) flare may herald a sustained loss of viral replication, but the relationship between virologic response, the extent of a flare, and pretreatment hepatitis B virus (HBV) DNA level has not been defined. We retrospectively examined the impact of an ALT flare on sustained virologic response in 121 interferon-treated patients and 42 untreated controls with either low-level (<100 pg/mL) or high-level (> or =100 pg/mL) viremia. The degree of ALT flare was classified as mild (increase in ALT of 86-171 IU/L above baseline), moderate (increase of 172 to 343 IU/L above baseline), and severe (increase of > or =344 IU/L above baseline). Undetectable serum HBV DNA and hepatitis B e antigen (HBeAg) loss were significantly more likely at the end of follow-up in patients having a flare (P =.0001 and.001, respectively). In the high viremia group, a proportionate increase in virologic response was observed as the degree of flare increased. By multivariate analysis, high baseline HBV DNA, high pretreatment ALT, and both moderate and severe ALT flare were independently predictive of a virologic response with severe flare being the most powerful predictor for a sustained loss of serum HBV DNA (odds ratio, 5.3; P =.004). Severe flare was predictive of a virologic response in the high but not low viremia group. We conclude that a virologic response in patients with high-level viremia is dependent on the degree of ALT flare. Induction of a robust flare may enhance virologic response when high-level viremia is detected.

Acute flares in chronic hepatitis B: the natural and unnatural history of an immunologically mediated liver disease.

Acute flares in chronic hepatitis B are common and may be caused by a number of identifiable and potentially treatable factors. The common link for many of these exacerbation episodes is a change in the immunologic response to hepatitis B virus (HBV), and this may have no identifiable cause or be triggered by an increase in viral replication or genotypic change. It is important to keep in mind the clinical situations in which patients are at increased risk of reactivated infection and secondary exacerbations. Reactivation is frequently induced by medical treatments such as cancer chemotherapy, antirejection drugs used in organ transplantation, and corticosteroids. The immunologic flares that often result from sudden withdrawal of these medications can be life-threatening unless recognized and treated promptly with antivirals, and there is increasing experience that preemptive antiviral treatment can diminish their occurrence and improve the outcome. The experience with lamivudine and other nucleoside analogues has increased our understanding of the molecular events behind hepatitis flares that occur when chronic hepatitis B is treated with drugs that potently inhibit HBV DNA polymerase. However, not all flares are explainable by events related to HBV infection alone. Depending on the population studied, as many as 20%-30% of flares may be caused by infection with other hepatotropic viruses, and this situation may inhibit HBV replication. Proper understanding of the etiology and effective treatment of acute flares in chronic hepatitis B requires an appreciation of high-risk clinical situations, assessment of HBV replication status, and testing for other viruses when appropriate.

A multicenter United States-Canadian trial to assess lamivudine monotherapy before and after liver transplantation for chronic hepatitis B.

Seventy-seven liver transplant candidates were enrolled in a multicenter study in which patients were treated with lamivudine (100 mg daily) without the adjunctive use of hepatitis B immune globulin. Treatment was begun while patients awaited liver transplantation and continued after transplantation. All were hepatitis B surface antigen (HBsAg) positive, and 61% had detectable hepatitis B e antigen (HBeAg) and HBV DNA when treatment was begun. Forty-seven underwent liver transplantation and 30 did not. Median study participation was 38 months (range, 2.7-48.5) in the transplanted patients and 26 months (range, 0.1-37) in the nontransplanted group. Twenty-five of 42 (60%) transplanted patients with 12 or more weeks of posttransplantation follow-up were HBsAg negative at the last study visit. At treatment week 156, 13 of 22 (59%) remained HBsAg negative, and all 9 reinfected patients were HBV-DNA positive before treatment. In the nontransplanted patients, HBeAg was initially detectable in 20 of 27 (74%) but this decreased to 3 of 17 (18%) after 104 weeks of treatment, and significant improvement in biochemical parameters was observed. HBV-DNA polymerase mutants were detected in 15 (21%) and 6 (20%) of the transplanted and nontransplanted patients, respectively. When compared with historical cohorts, lamivudine-treated patients appeared to have improved survival, and transplanted patients had a decrease in the rate of recurrent HBV infection. Lamivudine therapy was partially effective in preventing recurrent HBV infection when given before and after transplantation. Thus, future trials using a combination of HBIg and lamivudine are needed to assess the optimal prophylactic therapy.

Long-term mortality and morbidity of transfusion-associated non-A, non-B, and type C hepatitis: A National Heart, Lung, and Blood Institute collaborative study.

Persons with non-A, non-B hepatitis (cases) identified in 5 transfusion studies in the early 1970s have been followed ever since and compared for outcome with matched, transfused, non-hepatitis controls from the same studies. Previously, we reported no difference in all-cause mortality but slightly increased liver-related mortality between these cohorts after 18 years follow-up. We now present mortality and morbidity data after approximately 25 years of follow-up, restricted to the 3 studies with archived original sera. All-cause mortality was 67% among 222 hepatitis C-related cases and 65% among 377 controls (P = NS). Liver-related mortality was 4.1% and 1.3%, respectively (P =.05). Of 129 living persons with previously diagnosed transfusion-associated hepatitis (TAH), 90 (70%) had proven TAH-C, and 39 (30%), non-A-G hepatitis. Follow-up of the 90 TAH-C cases revealed viremia with chronic hepatitis in 38%, viremia without chronic hepatitis in 39%, anti-HCV without viremia in 17%, and no residual HCV markers in 7%. Thirty-five percent of 20 TAH-C patients biopsied for biochemically defined chronic hepatitis displayed cirrhosis, representing 17% of all those originally HCV-infected. Clinically evident liver disease was observed in 86% with cirrhosis but in only 23% with chronic hepatitis alone. Thirty percent of non-A, non-B hepatitis cases were unrelated to hepatitis viruses A,B,C, and G, suggesting another unidentified agent. In conclusion, all-cause mortality approximately 25 years after acute TAH-C is high but is no different between cases and controls. Liver-related mortality attributable to chronic hepatitis C, though low (<3%), is significantly higher among the cases. Among living patients originally HCV-infected, 23% have spontaneously lost HCV RNA.

Transplantation of livers from hbc Ab positive donors into HBc Ab negative recipients: a strategy and preliminary results.

Here we describe a strategy for using livers from hepatitis B core antibody (anti-HBc) positive donors in anti-HBc negative recipients and report our preliminary results. Adult anti-HBc negative recipients were immunized against hepatitis B virus (HBV) prior to transplantation. Liver biopsies from anti-HBc positive, HBs Ag negative donors were performed at the time of procurement to rule out acute hepatitis or chronic liver disease. Donor serum and liver samples were collected for HBV DNA analysis by PCR. Recipients were given HBIG (10000 units, i.v.) during the anhepatic phase of transplantation. Patients were treated with lamivudine (150 mg) beginning on postoperative day (POD) 1. If HBV DNA was not detected in either donor liver or serum by PCR, recipient antiviral therapy was stopped. If donor liver and serum were positive for HBV DNA by PCR, the recipient was maintained on combination lamivudine and HBIG therapy. If HBV DNA was detected in donor liver but not in donor serum, the patient was managed on lamivudine therapy alone. Between February 1999 and June 2000, six anti-HBc negative recipients received liver transplants from anti-HBc positive donors. PCR analysis of serum from the six donors was negative for HBV DNA in each, while donor liver PCR analysis was positive in five of six for HBV DNA. Accordingly, all patients were given HBIG in the anhepatic phase of transplantation and five of six were maintained on daily lamivudine therapy. Follow-up periods have ranged from 2 to 18 months. There has been no emergence of de novo hepatitis B. Serial serum HBs Ag and HBV DNA assays have all proven negative. Moreover, while on lamivudine therapy, 2 patients now have undetectable HBV DNA in hepatic allograft biopsies by PCR analysis. Our strategy for using livers from anti-HBc donors has yielded promising initial results. De novo hepatitis B has not occurred and our data suggest residual hepatitis B virus may be eradicated in recipients maintained on lamivudine therapy.

Antiviral therapy to prevent and treat hepatitis B virus infection in hepatic allografts.

Hepatitis B infection of a liver allograft can have serious consequences including a negative influence on the probability of survival. Therefore, there is a need for very effective antiviral therapy for transplant recipients. In this article the early experience with nucleoside analogue antiviral agents, both to prevent and to treat hepatitis B in liver allografts, is reviewed. There are several important characteristics of these agents that are already apparent. Ganciclovir and famciclovir have limited efficacy in treating infections when they are used alone. These compounds might be beneficial if used after resistance develops to other drugs or when used in combination with other agents. Lamivudine is effective for about two-thirds of patients in preventing and treating hepatitis B infection in allografts. Hepatitis B immune globulin (HBIg) is known to increase the efficacy of lamivudine in preventing infection. A large study to further characterize this combination therapy is being organized. Resistance to famciclovir and lamivudine can occur if they are used alone for a long time. In order to lower the incidence of drug resistance, it may be necessary to utilize combinations of nucleoside analogues.

Posttransplantation: emerging and future therapies.

Liver transplantation in patients infected with hepatitis B virus (HBV) commonly results in reinfection that, if untreated, often compromises the viability of the allograft and negatively influences survival. Posttransplant treatment with hepatitis B immune globulin (HBIG) is now the standard of care, but patients appear to require lifelong treatment to prevent reinfection. In the past several years, new management strategies in patients with HBV have been developed, with an aim to decrease HBV-DNA replication before transplantation. Such an approach should increase the success of transplantation by decreasing the risk of reinfection and thus preventing recurrent disease posttransplantation. Nucleoside analogues, either alone or in conjunction with HBIG, are currently in use and are being studied in clinical trials as a means of preventing viral recurrence. Ganciclovir, famciclovir, and lamivudine all have demonstrated efficacy, although they vary in terms of effectiveness. Resistance may develop with the use of these agents and leads to reinfection by the mutant virus. Combination therapy may minimize the risk of viral mutation. Research continues to search for more effective ways to prevent and, if necessary, treat viral recurrence in patients undergoing liver transplantation for HBV.

Case studies of the hepatitis B patient: a panel discussion.

In recent years, there have been significant advances in the treatment of patients with hepatitis B who are candidates for liver transplantation. This includes the prevention and management of hepatitis B posttransplantation. However, there is no established protocol for treating these patients. Ultimately, the goal would be to have patients HBV-DNA negative pretransplantation and then to prevent HBV recurrence posttransplantation to help ensure their quality of life. Several clinical case scenarios are presented and possible treatment solutions have been suggested. The timing of a transplant is critical due to the risk of viral mutation while the patient is on a nucleoside analogue antiviral agent and waiting for an organ. One successful option might be to start therapy pretransplant and continue it posttransplant. Combination therapy appears to provide the most effective course of treatment. This should include a nucleoside analogue and patients should be covered with hepatitis B immune globulin throughout the course of therapy. Several other variations of combination therapy are discussed, but many clinical issues remain to be resolved. Guidelines for future studies designed to answer these questions are proposed.

Lamivudine as initial treatment for chronic hepatitis B in the United States.

BACKGROUND AND METHODS: Although the nucleoside analogue lamivudine has shown promise in patients with chronic hepatitis B, long-term data on patients from the United States are lacking. We randomly assigned previously untreated patients with chronic hepatitis B to receive either 100 mg of oral lamivudine or placebo daily for 52 weeks. We then followed them for an additional 16 weeks to evaluate post-treatment safety and the durability of responses. The primary end point with respect to efficacy was a reduction of at least 2 points in the score on the Histologic Activity Index. On this scale, scores can range from 0 (normal) to 22 (most severe abnormalities). RESULTS: Of the 143 randomized patients, 137 were included in the efficacy analysis: 66 in the lamivudine group and 71 in the placebo group. The other six patients were excluded at the base-line visit because of the absence of a documented history of hepatitis B surface antigen for at least six months. After 52 weeks of treatment, lamivudine recipients were more likely than placebo recipients to have a histologic response (52 percent vs. 23 percent, P<0.001), loss of hepatitis B e antigen (HBeAg) in serum (32 percent vs. 11 percent, P=0.003), sustained suppression of serum hepatitis B virus (HBV) DNA to undetectable levels (44 percent vs. 16 percent, P<0.001), and sustained normalization of serum alanine aminotransferase levels (41 percent vs. 7 percent, P<0.001), and they were less likely to have increased hepatic fibrosis (5 percent vs. 20 percent, P=0.01). Lamivudine recipients were also more likely to undergo HBeAg seroconversion, defined as the loss of HBeAg, undetectable levels of serum HBV DNA, and the appearance of antibodies against HBeAg (17 percent vs. 6 percent, P=0.04). HBeAg responses persisted in most patients for 16 weeks after the discontinuation of treatment. Lamivudine was well tolerated. Self-limited post-treatment elevations in serum alanine aminotransferase were more common in lamivudine recipients: 25 percent had serum alanine aminotransferase levels that were at least three times base-line levels, as compared with 8 percent of placebo recipients (P=0.01). The clinical condition of all patients remained stable during the study. CONCLUSIONS: In U.S. patients with previously untreated chronic hepatitis B, one year of lamivudine therapy had favorable effects on histologic, virologic, and biochemical features of the disease and was well tolerated. HBeAg responses were generally sustained after treatment.

The roles of amantadine, rimantadine, ursodeoxycholic acid, and NSAIDs, alone or in combination with alpha interferons, in the treatment of chronic hepatitis C.

Although alpha interferons are currently the standard treatments for chronic hepatitis C, they are effective in only 15% to 20% of patients. This low success rate has prompted research into new approaches for maximizing responses to alpha interferons. A variety of drugs have been investigated alone or in combination with alpha interferons. Of these agents, ribavirin is currently the most promising adjuvant, and the combination therapy of ribavirin plus recombinant interferon alfa-2b is reviewed in detail elsewhere in this issue (see Davis article, pp. 49-55; and McHutchison article, pp. 57-65). This article reviews the literature concerning studies of amantadine, rimantadine, ursodeoxycholic acid (UDCA), and nonsteroidal anti-inflammatory drugs (NSAIDs), which are the most commonly used alternatives to ribavirin. As of this writing, virologic response rates have been unsatisfactory when these agents are used as monotherapies. Furthermore, combining alpha interferons with either UDCA or NSAIDs does not appear to improve sustained virologic response rates. However, combination regimens composed of an alpha interferon plus amantadine, or an alpha interferon plus rimantadine, or triple therapy with either amantadine or rimantadine plus an alpha interferon and ribavirin, warrant further investigation.

Association of diabetes mellitus and chronic hepatitis C virus infection.

While patients with liver disease are known to have a higher prevalence of glucose intolerance, preliminary studies suggest that hepatitis C virus (HCV) infection may be an additional risk factor for the development of diabetes mellitus. To further study the correlation of HCV infection and diabetes, we performed a retrospective analysis of 1,117 patients with chronic viral hepatitis and analyzed whether age, sex, race, hepatitis B virus (HBV) infection, HCV infection, and cirrhosis were independently associated with diabetes. In addition, a case-control study was conducted to determine the seroprevalence of HCV infection in a cohort of 594 diabetics and 377 clinic patients assessed for thyroid disease. In the former study after the exclusion of patients with conditions predisposing to hyperglycemia, diabetes was observed in 21% of HCV-infected patients compared with 12% of HBV-infected subjects (P =.0004). Multivariate analysis revealed that HCV infection (P =.02) and age (P =.01) were independent predictors of diabetes. In the diabetes cohort, 4.2% of patients were found to be infected with HCV compared with 1.6% of control patients (P =.02). HCV genotype 2a was observed in 29% of HCV-RNA-positive diabetic patients versus 3% of local HCV-infected controls (P <.005). In conclusion, the data suggest a relatively strong association between HCV infection and diabetes, because diabetics have an increased frequency of HCV infection, particularly with genotype 2a. Furthermore, it is possible that HCV infection may serve as an additional risk factor for the development of diabetes, beyond that attributable to chronic liver disease alone.

Molecular basis for persistent hepatitis B virus infection in the liver after clearance of serum hepatitis B surface antigen.

Hepatitis B virus (HBV) DNA has been detected by polymerase chain reaction (PCR) in the liver of patients with resolved chronic HBV infection and sustained clearance of hepatitis B surface antigen (HBsAg) from serum. However, it is unknown whether the virus is transcriptionally active at this time or if the covalently closed circular (CCC) replicative intermediate of HBV DNA can still be detected. Therefore, hepatic nucleic acid extracts from seven patients who had cleared serum HBsAg were assessed by (PCR) for either reverse-transcribed HBV RNA, or an intact direct repeat region of the HBV genome indicative of the CCC replicative intermediate of HBV DNA. HBV transcripts were detected in four of seven patients in the study group, whereas an intact direct repeat region of the HBV genome was detected in three. Evidence for viral transcription and replication was more frequently detected in patients who had recently cleared serum HBsAg, but HBV RNA was also detected in one patient 5 years after HBsAg clearance, and an intact direct repeat region of HBV DNA was detected in another subject at nearly 4 years after resolution of disease. Therefore, hepatic HBV transcription may be associated with replicative intermediates of persistent HBV DNA in patients who have cleared HBsAg from serum, suggesting that, on occasion, HBV may not be in a latent state but undergoing low-level replication.

The role of liver biopsy in hepatitis C.

This article reviews the ways in which liver biopsy provides a resource to the clinician when making management decisions for patients with chronic hepatitis C. Liver biopsy provides information about the extent and distribution of inflammation and allows grading and staging of the disease (the amount of fibrosis). Furthermore, the liver biopsy allows some assessment of the rate of disease progression whenever the date of onset of infection is known. The presence of diffuse fibrosis or cirrhosis correlates with a lower likelihood of response to antiviral therapy, and the finding of severe necroinflammatory and fibrotic changes is helpful in determining the relative importance of beginning treatment early rather than deferring therapy. The importance of liver biopsy in the selection of patients for treatment is underscored by the fact that hepatitis C is a condition in which therapy is currently unable to successfully treat the majority of patients. There are no strong correlations between serum viral RNA, alanine aminotransferase (ALT) levels, and liver histopathology; therefore, the utility of aminotransferases and hepatitis C virus (HCV) RNA as surrogate tests for measuring disease activity in individual cases is limited. It is concluded that liver biopsy should be performed before initiating interferon therapy. At the present time, it is not known if and when repeat histological assessment is necessary. Preferably, it should only be performed in instances when the findings from the biopsy are likely to lead to a change in management of the patient.

Comparison of quantitative HCV RNA assays in chronic hepatitis C.

We compared the relative sensitivities of first-and-second generation branched nucleotide assays (Quantiplex HCV RNA 1.0 and 2.0, respectively, Chiron, Emeryville, Calif) for the detection of hepatitis C virus (HCV) RNA to that of a commercially available quantitative reverse transcriptase polymerase chain reaction (RT-PCR) method (Monitor, Roche Molecular Systems, Nutley, NJ) in 53 patients with chronic hepatitis C. The sensitivities of the second-generation branched DNA (bDNA) and RT-PCR assays were similar (91% and 92%, respectively), and both were significantly more sensitive (P < .001) than the first-generation method. Moreover, both assays detected HCV RNA in all 11 patients with type 2a, 2b, or 3a genotypes vs 45% with the HCV RNA 1.0 bDNA assay. We examined 174 serum samples by the bDNA 2.0 and RT-PCR assays. Major quantification differences were noted on a given specimen with the RT-PCR method reporting values an average 41-fold lower (range, 0-703-fold) than those obtained with the bDNA assay. We conclude that both methods can be used to detect HCV RNA in patients who are infected with the genotypes that are most commonly encountered in the United States. The HCV RNA 2.0 bDNA assay may offer advantages when attempting to quantify high-level viremia.

Morbidity of chronic hepatitis C as seen in a tertiary care medical center.

We studied the morbidity of chronic hepatitis C in patients referred to a tertiary care medical facility. The medical records of 500 consecutive cases of chronic hepatitis C were examined for the following: (1) source and time of exposure, (2) signs and symptoms of liver disease, (3) degree of alcohol intake, (4) liver biopsy findings, (5) extrahepatic disease manifestations, and (6) coexisting illnesses that could have an impact on morbidity. Morbidity and histologic findings were evaluated in relation to the duration of hepatitis C. The onset of infection could be determined in 376 patients (75%). A close relationship between the length of infection and disease features was not observed. Fatigue was common at all stages of infection. Whereas cirrhosis occurred more frequently in patients with disease of long duration, 15-24% of patients had signs of advanced liver disease (ascites, encephalopathy, thrombocytopenia) within six years of exposure. Overt extrahepatic manifestations of chronic hepatitis C occurred infrequently, and depression was reported in 24% of untreated patients. In conclusion, in patients referred to a tertiary care setting, chronic hepatitis C is often associated with significant morbidity.

Response to higher doses of interferon alfa-2b in patients with chronic hepatitis C: a randomized multicenter trial. Hepatitis Interventional Therapy Group.

To evaluate response rates to 3, 5, or 10 million units (MU) of interferon alfa-2b, given thrice weekly, and to determine whether higher doses of interferon increase the likelihood or durability of the response, a multicenter, randomized trial was performed at nine academic medical centers in the United States. Two hundred forty eight patients with chronic hepatitis C were randomized to receive 3, 5, or 10 MU of interferon alfa-2b thrice weekly for 12 weeks. Based on the alanine aminotransferase (ALT) response at treatment-week 12, the patients were rerandomized to additional therapy at the same or at increased doses for an additional 12 to 36 weeks; in the case of no response to the highest dose, the patients were discontinued from the study. Serum ALT concentrations and liver histology were measured. The overall complete response rates to 3, 5, or 10 MU were not different at treatment-week 12 (31% vs. 42% vs. 40%, not significant). The majority of week-12 responders continued to respond during additional treatment. When the treatment was discontinued, 15.4% to 19.0% of patients maintained their response. Of the nonresponders to 3 MU at week 12, who were continued on 3 MU for an additional 12 weeks, none responded. However, response to additional therapy occurred in 12% of week-12 nonresponders, whose dose was escalated from 3 or 5 MU to 10 MU. The only baseline features associated with the treatment response were the absence of fibrosis or cirrhosis on the pretreatment liver biopsy and viral genotype. We conclude that the initial response to interferon in patients with chronic hepatitis C is not increased by treatment with higher doses of the drug. Patients who do not respond to 3 MU by treatment-week 12 will not respond with continued therapy at that dose; however, a proportion of patients who do not respond to 12 weeks of treatment with 3 or 5 MU may respond to higher doses. Although the long-term sustained response rates are marginally increased with interferon doses above 3 MU three times per week, the side effects are difficult to tolerate. The analysis of baseline factors in relation to response identified no single baseline factor associated with a low-enough response rate to warrant withholding interferon therapy from patients with chronic hepatitis C.