According to World Health Organization, approximately 170 million people worldwide are infected with hepatitis C virus (HCV), including approximately 500,000 to 700,000 people in Poland (1). HCV infection is usually asymptomatic, with a tendency to become chronic. It may lead to liver cirrhosis and neoplasm. In adults, approximately 15% to 50% infected with HCV eliminate the virus spontaneously, whereas the remaining 50% to 85% develop chronic hepatitis (2). In approximately 20% of patients with chronic hepatitis C, liver cirrhosis will develop within 20 years (3). In this group, liver insufficiency signs will develop in 6%, and in 4%, primary liver cancer (4).
According to some authors, spontaneous elimination of the virus is more common in children than adults, and the tendency for liver fibrosis and cirrhosis is much smaller (5,6). Severe liver disease may develop within 10 years from the onset of infection, with a <2% risk during the pediatric age (7). Despite the fact that the course of HCV infection is milder in children, approximately 4% to 6% of children with chronic hepatitis C show signs of advanced liver fibrosis or cirrhosis (6), and each year 4 to 5 children in the United States require liver transplant because of insufficiency (8). Despite recent developments in the medical sciences, the efficacy of available drugs is still limited. The aim of chronic hepatitis treatment is achieving sustained viral response (SVR), which decreases the risk of cirrhosis and hepatocarcinogenesis and improves prognosis.
In 2000, pegylated interferon (IFN) was introduced into the treatment regimen; by binding with polyethylene glycol, the molecular weight increased, and renal clearance and halftime increased. Thus, it is now possible to administer the drug once per week (9). In 2008, the US Food and Drug Administration and in 2009 the European Medicines Agency approved pegylated IFN-α2b with ribavirin in the treatment of chronic hepatitis C in children older than 3 years in the United States and Europe (7,10). This is consistent with the recommendation of the Polish Group of Experts for HCV 2011 (11). The use of pegylated IFN-α2a was approved by the Food and Drug Administration in 2011 for children 5 years and older. To improve the effects of treatment and minimize adverse effects and costs, as well as to increase the quality of life of our patients, new ways of treatment and prognostic criteria in antiviral therapy were investigated. The aim of our study was evaluation of the efficacy of combined treatment using pegylated IFN-α2b with ribavirin in children and adolescents with chronic hepatitis C and determination of value in the selected parameters in the prognosis of treatment effects.
The study was based on retrospective analysis of treatment using pegylated IFN-α2b with ribavirin in children and adolescents with chronic hepatitis C between 2004 and 2007 in the Polish Mother's Memorial Hospital, Research Institute in Lodz, and Infectious Diseases and Hepatology of Developmental Age Department, Collegium Medicum, Mikołaj Kopernik University in Bydgoszcz. The study comprised both treatment-naïve and previously treated patients.
The study comprised 79 patients, 59 boys and 20 girls, ages 14.7 ± 2.5 years (max 18 years, min 8 years), with chronic hepatitis C, treated with pegylated IFN-α2b combined with ribavirin. The diagnosis of chronic hepatitis C was established on the basis of presence of anti-HCV antibodies for at least 6 months, constant or periodical increase in the activity of alanine aminotransferase, and the presence of HCV RNA in blood serum. In all of the patients, hepatitis from other causes was excluded (autoimmune hepatitis and hepatitis caused by hepatotropic viruses).
Mean disease duration was 5.3 ± 4.0 years (max 16 years, min 6 months). In 43 patients, before our treatment, recombined IFN with ribavirin was used with no success (7 patients obtained another course of treatment: 5 patients recombined IFN in monotherapy, and 2 patients recombined IFN with ribavirin).
In all of the patients, liver biopsy was performed within 12 months before the onset of treatment. Biopsies were evaluated by a pathologist according to the modified Scheuer classification and were assigned a grade for necroinflammation between 0 and 4 and stage for fibrosis between 0 and 4 (12). The liver biopsy data revealed necrotic-inflammatory changes (grading) up to 0.93 ± 0.56 points on an average (max 2, min 0 points) and fibrosis (staging) up to 0.97 ± 0.75 points on average (max 3, min 0 points).
In the studied group, 54 patients were infected with genotype 1 HCV and 25 patients with genotype 4. In 34 of 76 (44.7%) patients, viremia was determined as >500,000 IU/mL, in 42 of 76 (55.3%) as ≤500,000 IU/mL, and in 3 cases, only a qualitative test was done. Mean alanine aminotransferase (ALT) concentration was 48.6 ± 24.7 IU/L (max 158, min 11 IU/L). The demographic and clinical characteristics of the analyzed patients, stratified by HCV genotype, are presented in Table 1.
All of the patients were treated with pegylated IFN-α2b (PegIntron, Schering-Plough, Kenilworth, NJ) and ribavirin (Rebetol, Schering-Plough) for 48 weeks. Pegylated IFN-α2b was administered subcutaneously once weekly at 1.5 μg/kg, and ribavirin orally 15 mg · kg−1 · day−1 in 1 dose.
Demographic characteristics and other standard clinical data were obtained from patients’ clinical documentation. The parents and children were informed about the benefits and inconveniences of the applied treatment. Before the onset of therapy, parents of all of the patients gave written consent to combine treatment with pegylated IFN and ribavirin, and to use their data in future evaluation of this nonstandard therapy. Consent was also obtained from the Bioethics Committee, Polish Mother's Memorial Hospital, Research Institute in Lodz and Collegium Medicum, Mikołaj Kopernik University in Bydgoszcz for the above-described treatment and the conduct of the study.
In all of the patients before the onset of treatment, the following were evaluated: level of HCV RNA in blood serum (in 3 patients only qualitative examination was confirmed), HCV genotype, and the activity of ALT (normal range ALT <41 IU/L for boys and <31 IU/L for girls). Then, the presence of HCV RNA in blood serum was assessed qualitatively and quantitatively after 3 and 12 months of treatment and after 6 months from treatment completion (the test was performed in 65, 71, and 79 patients, respectively). We have also analyzed available tests (21 patients) for HCV RNA in blood serum after 12 months from treatment termination. The activity of ALT was assessed after 12, 24, and 48 weeks of treatment and 24 weeks after the treatment was discontinued.
The proportion of patients who attained SVR was the primary efficacy variable. Secondary endpoints were virological response rate and end-of-treatment response (ETR) rate. Undetectable serum HCV RNA level after 12 weeks of treatment was defined as early viral response (EVR), after 48 weeks of treatment as ETR, and after 6 months from treatment discontinuation as SVR. Relapse was recurrence of viremia within 6 months from treatment discontinuation, if there was no viremia after 12 months of treatment. Viral breakthrough was defined as viremia increase during treatment up to detectable levels after an earlier period of undetectable viremia (13).
During treatment, the tolerance of therapy was monitored by physical examination and laboratory tests (hematological, biochemical, and serological). Hematological abnormalities were determined as anemia, leucopenia, and thrombocytopenia according to the normal range for a given age and sex from the laboratory, which performed tests (anemia: in children 8–12 years and girls older than 12 years, Hb <12.0 g/dL, in boys older than 12 years Hb <13 g/dL; leucopenia: in all patients, WBC count <4.0 g/L; thrombocytopenia: in all patients, platelet count <150 g/L).
The presence of HCV RNA was evaluated using Cobas Amplicor HCV version 2.0 qualitative test (Roche Molecular Systems, Branchburg, NJ) with a lower limit of detection of <50 IU/mL, whereas the level of HCV RNA with a quantitative test from COBAS AmpliPrep/COBAS TaqMan HCV Test (Roche Diagnostics Ltd, Rotkreuz, Switzerland) had a lower limit of detection of <43 IU/mL. The genotypes of HCV were identified by performing the VERSANT HCV Genotype 2.0 Assay LiPA (Siemens Healthcare Diagnostics, Malvern, PA) or INNOGENETICS INNO-LiPA HCV II test (Innogenetics, Ghent, Belgium).
For all of the parameters expressed in interval scale, the minimum and the maximum were given, and the mean and standard deviation were calculated. Normality of distribution was assessed by the Shapiro-Wilk test at P = 0.05.
Comparisons between groups of independent samples, the distribution of which was similar to normal distribution, were performed using the Student t test for independent variables, and if the distribution was not normal or parameters were expressed in rank order scale, by the Mann-Whitney U test. Comparisons of dependent samples, the distribution of which was similar to normal distribution, were performed using the Student t test and the Wilcoxon test in other cases. For parameters in nominal scale, the structure and occurrence of particular classes were evaluated. Comparisons between groups and dependence were studied by the χ 2 test. If conditions for using χ 2 were not fulfilled, or in case of 4-fold table comparison of 2 frequencies and dependence, the Fisher exact test was used. Statistical calculations were performed using the CSS Statistica program version 6.0 (StatSoft, Tulsa, OK).
Response to Treatment
After 3 months of treatment in all patients, mean ALT concentration decreased significantly to 34.7 ± 23.7 IU/L (max 158, min 7 IU/L). Among 65 patients in whom HCV RNA was analyzed, EVR was observed in 28 (43.1%).
After 12 months of treatment, mean ALT concentration in the whole group was 28.7 ± 18.5 IU/L (max 108 IU/L, min 6 IU/L) and was significantly lower than after 3 months of treatment. Among 71 patients in whom serum HCV RNA was studied after 12 months of treatment, viremia was below detectability level (ETR) in 34 (47.9%) patients (37 patients had detectable viremia).
In 6 months from therapy, discontinuation among 79 treated patients, viremia was undetectable (SVR) in 35 (44.3%). Mean ALT concentration in the whole group was 30.3 ± 21.6 IU/L.
Among 28 patients who attained EVR, 23 achieved SVR; in the remaining 5 patients with no viral response (in whom viral response was not maintained), based on the results of tests performed after 24 and/or 48 weeks of treatment, breakthrough was diagnosed in 3 cases and relapse in 2 cases. Moreover, in 1 child after 6 months of treatment (EVR was not studied), viral response was attained, followed by a breakthrough. The calculated positive prognostic value of EVR for SVR was 82.1% (23/28).
In the studied group, 37 patients (from 65 examined at that time) did not attain EVR. Of those 37 who did not have EVR, 35 patients did not achieve SVR, and the remaining 2 patients after 12 months of treatment demonstrated undetectable viremia, and then SVR. Negative prognostic value—no SVR with no EVR in the whole group—was determined as 94.6% (35/37). In all 21 (100%) patients with SVR, in whom examinations were performed after at least 12 months from treatment termination (among 35 patients with SVR), inhibition of HCV replication was sustained (viremia below detectability level) (Table 2).
As shown in Table 2 there were no statistically significant differences in the age, sex, liver histology, initial ALT activity, and viral load between responders and nonresponders. Despite the lack of statistical significance, we have noticed a tendency for more pronounced changes in liver histopathology, grading, and staging in nonresponders. Moreover, significantly shorter duration of infection in responders, as compared with patients not responding to therapy, has been observed (3.9 ± 3.7 vs 6.4 ± 3.8 years; P < 0.01).
Response to Treatment Depending on Earlier Therapy
Patients not treated before significantly more frequently attained EVR, ETR, and SVR (16/25: 64%, 21/32: 65.6%, and 23/36: 63.9%, respectively) as compared with patients treated previously (12/40: 30%, 13/39: 33.3%, and 12/43: 27.9%, respectively) (P < 0.01, P < 0.01, and P < 0.01, respectively) (Table 3).
Response to Treatment Depending on HCV Genotype
There were no significant differences in response to treatment between patients infected with genotypes 1 and 4 HCV both in the whole group (Table 1), and in the group of re-treated patients and treatment-naïve patients (Table 3); however, in treatment-naïve patients infected with genotype 4, there was a tendency toward more frequent EVR, ETR, and SVR as compared with patients infected with genotype 1 (100% vs 60.9%, 71.4% vs 64.0%, and 77.8% vs 59.3%, respectively; the differences were not significant statistically). No such trend was observed in re-treated patients. In patients infected with genotypes 1 and 4, SVR was significantly more common in treatment-naïve patients. Among patients infected with genotype 1, ETR was more frequent in treatment-naïve patients (Table 3).
During combined treatment, we observed numerous adverse effects. The most common were leucopenia, parainfluenza symptoms, fever, headaches, loss of appetite (which in some patients was connected with weight loss by >10%), hair loss, thrombocytopenia, anemia, abdominal pain, reaction at injection site, and mood disorders. The observed adverse effects did not require treatment discontinuation in any patient. The main limitation of this study was its retrospective character; thus, there are no data available for detailed discussion of observed adverse effects.
Despite numerous studies, the results of treatment of chronic hepatitis C, particularly in genotypes 1 and 4, have improved but are still not satisfactory. The aim of treatment is inhibition of HCV replication and decrease of liver changes. The efficacy of treatment is evaluated on the basis of percentage of patients attaining SVR, that is, elimination of HCV RNA from blood serum in 6 months after treatment termination. Recent introduction of combined therapy of pegylated IFN with ribavirin into standards of treatment of chronic hepatitis C has become an important step toward disease eradication. Wirth et al (14) describe a therapeutic success—SVR in 65% of treated children; in those infected with genotype 1 HCV, SVR was attained in 53% and in those infected with genotype 4 HCV infection, SVR was attained in 80%. Schwarz et al (15), in their multicenter randomized controlled study described the percentage of children attaining SVR at 53% (47% in genotype 1 HCV and 80% in genotype 2–6 HCV infection, respectively); however, in the study by Sokal et al (16), 57% of patients infected with genotypes 1, 4, 5, or 6 attained SVR. Similar effects have been described in adults (10,17); however, this population can now benefit from new methods of treatment (18). Our study concentrated on children infected with HCV genotypes 1 and 4. The percentage of patients attaining SVR reached 44.3%, similarly in patients with genotypes 1 and 4 HCV (44.4% and 44%, respectively). Relatively low percentage of good response to treatment in the whole group, as compared with the above-mentioned results of other authors, may result from the structure of the study group. In our group, more than half of the patients (54.4%) were previously treated with IFN in monotherapy or in combination with ribavirin. In the group of treatment-naïve patients, the percentage of SVR was 63.9% and was significantly higher than in the study by Schwarz et al (15) or in the study by Sokal et al (16).
In patients treated for the first time and infected with genotype 1 HCV, the percentage of SVR (59.3%) was similar to that obtained by Wirth et al (14) and slightly higher than in the study by Schwarz et al (15). Similarly, in patients infected with genotype 4 HCV, the percentage of SVR (77.8%) did not differ significantly from the values reported by Wirth et al (14) and Schwarz et al (15). In the above-mentioned studies, genotype was the main factor determining response to treatment, whereas in our study, possibly because of the small number of patients, there were no such statistically significant correlations; however, in the group of patients infected with genotype 1, relapse or breakthrough was observed twice as frequently as in those infected with genotype 4 HCV (in 5/54, 9.3% and 1/25, 4%, respectively), although the difference was not statistically significant. Similarly, Wirth et al (14) observed relapses only in patients infected with genotype 1 HCV (12% of children).
According to the European Association for the Study of the Liver, stage of liver fibrosis is one of the strongest predictors of SVR (19). In the present study, despite the lack of statistical significance, we have noticed a tendency for more pronounced changes in liver histopathology, grading, and staging in non-responders. It is possible, however, that lack of statistical significance in this case resulted from low advancement of fibrosis observed in our group of patients. In the present study, similarly as in the report by Jara et al (20), there was no correlation between the level of viremia or ALT activity and response to treatment, although such correlation has been described by other authors (14,21).
In the present study, we stress the prognostic value of EVR for SVR. In our study, in all of the positive patients the prognostic value of EVR for attaining SVR was 82.1%. Because of the fact that viremia was evaluated semiquantitatively in some patients, in the qualification for EVR, the degree of viremia decrease was not included. Similar percentage of patients with EVR attaining SVR (81%) was described by Sokal et al. It is noteworthy that SVR attained in the study group was permanent and lasted for the next 6 months in all of the patients, regardless of the genotype or previous ineffective therapies. Similarly, Schwarz et al (15) described persistence of SVR in all of the children in the following months. Also in the study by Swain et al in an adult population, almost all of the patients (99.1%) showed good virological repose after 4 years, and virus replication seen in 0.9% was because of both reinfection and relapse (21).
In many treatment regimens, patients who do not attain at least partial response are disqualified from further treatment. In the present study, negative predictive value of EVR for SVR, although high (94.6%), suggests that a small number of patients (2 patients infected with genotype 1) will not attain good response should their therapy be discontinued earlier. Also in the study by Schwarz et al (15), SVR but no EVR was seen in 3 children (7%) infected with genotype 1 HCV, and in the study by Davis and Wong (22), SVR but no EVR was seen in 1.6% of patients. Sokal et al (16) among 20 patients infected with genotypes 1, 4, 5, or 6 who did not have an EVR, SVR was not observed in 14 (predictive value of EVR for SVR 74%). Moreover, termination of therapy seems controversial in view of the reports describing improvement of liver histopathology, decrease, or even elimination of extrahepatic manifestations of the disease (23) in the course of combined treatment. The available reports suggest improvement in liver histopathology after treatment with IFN-α or pegylated IFN-α also in patients who do not attain permanent viral response (24,25).
On the contrary, inconvenience of treatment, possibility of adverse effects, and high cost of ineffective treatment in patients, who only in small percentages will respond well, make the decision of treatment continuation difficult. The above observations prompt a further search for new, more effective methods of treatment, particularly in patients who did not response well to the first course of therapy.
Combined therapy with pegylated IFN-α2b and ribavirin in children and adolescents with chronic hepatitis C, infected with HCV genotypes 1 and 4, is more effective in patients treated for the first time (63.9%), as compared with retherapy cases (27.9%). In all of the patients with SVR, virological response was maintained for at least the next 6 months. During treatment, numerous adverse effects have been observed, but they were not so severe as to discontinue therapy. Limited efficacy and numerous adverse effects of the applied treatment prompt further search of new, more effective methods of treatment, in particular for patients who did not respond well to the first course of therapy.
The authors thank Dr J. Kups-Rzepecka for the significant contribution in data collection.
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