Viral interaction and responses in chronic hepatitis C and B coinfected patients with interferon-alpha plus ribavirin combination therapy

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1 Antiviral Therapy 10: Viral interaction and responses in chronic hepatitis C and B coinfected patients with interferon-alpha plus ribavirin combination therapy Wan-Long Chuang, Chia-Yen Dai, Wen-Yu Chang, Li-Po Lee, Zu-Yau Lin, Shinn-Cherng Chen, Ming-Yuh Hsieh, Liang-Yen Wang and Ming-Lung Yu* Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan *Corresponding author: Tel: ext. 7475; Fax: ; fishya@ms14.hinet.net, d780178@kmu.edu.tw Background/aims: We conducted a case-control study to investigate the efficacy of interferon-alpha (IFN-α) and ribavirin combination therapy for patients with chronic hepatitis C and B virus (HCV/HBV) coinfection and to elucidate the interaction of these two viruses. Methods: Forty-two chronic HCV/HBV-coinfected patients (29 IFN-naive, 13 IFN-relapsed) and 84 HCV-monoinfected controls, matched for age, sex and previous history of IFN-α therapy, were enrolled. All patients were treated with IFN-α-2b 6 MU three-times weekly plus ribavirin mg daily for 24 weeks. Serum HCV RNA and HBV DNA were determined every 24 weeks for 72 weeks. Results: The rate of HCV sustained virological response (SVR) was comparable among IFN-naive and IFN-relapsed HCV/HBV-coinfected patients and IFN-naive and IFNrelapsed HCV-monoinfected patients (69.0%, 69.2%, 67.2% and 57.7%, respectively; intention-to-treat analysis). HCV genotype 1b, high pretreatment HCV RNA levels and liver fibrosis were significantly associated with a lower HCV SVR. Of 16 baseline HBV viraemic patients, five (31.3%) achieved HBV SVR, which correlated negatively to HCV genotype non-1b and HCV SVR. Only one (6.3%) had simultaneous seroclearance of HCV and HBV. Antibodies to HBV surface antigen seroconversion developed in five (11.9%) patients during long-term follow-up. HCV responders had significantly higher rates of HBV DNA resurgence than HCV non-responders during and after treatment. Reciprocal viral interference was noted between HCV and HBV after IFN-α/ribavirin therapy. Conclusions: IFN-α/ribavirin combination therapy is effective for HCV/HBV-coinfected patients in eradicating HCV infection and might promote HBV seroclearance, and there is a mutual viral response and reciprocal viral interaction between HBV and HCV. Introduction Hepatitis B virus (HBV) and hepatitis C virus (HCV) are two major aetiological agents in parenterally transmitted hepatitis that frequently cause persistent infections leading to chronic liver disease and primary hepatocellular carcinoma [1 3]. Although most people have only one viral infection, HCV/HBV coinfection is not uncommon in HBV endemic areas and is present in 10 40% of patients with chronic hepatitis in Taiwan and Europe [1,3 5]. Previous studies have indicated that progression from chronic hepatitis to cirrhosis and hepatocellular carcinoma is accelerated by HCV/HBV coinfection [1,3,4]. Interferon-alpha (IFN-α) treatment is effective for chronic hepatitis B (CHB) or chronic hepatitis C (CHC) monoinfection [2,6], but results in a sustained virological response (SVR) in only 12 30% of CHC patients [2,7] and only approximately one-third of CHB patients respond to IFN therapy [6]. However, IFN-α alone is ineffective in clearing HCV in HCV/HBV-coinfected patients [5,8 10]. A limited study showed that high doses of IFN-α monotherapy cleared HCV viraemia in 31% (5/16) of HCV/HBV-coinfected patients [11]. These results were inadequate and the HCV/HBV-coinfected patients were categorized as difficult-to-treat patients with hepatitis C in the National Institutes of Health Consensus Development [12]. A greater efficacy in treatment of CHC has been observed using IFN-α/ribavirin combination therapy [13,14], leading to this combination being a recommended therapy for CHC [15]. It clears HCV in 30 60% of IFN-naive or previously IFN-relapsed CHC patients [2,13,14,16]. A pilot study showed that IFN-α/ribavirin combination therapy is effective for anti-hepatitis B e antigen (anti-hbe)-positive CHB patients who have failed previous IFN therapy [17]. However, little is known about the efficacy of 2005 International Medical Press 125

2 W-L Chuang et al. IFN-α/ribavirin combination therapy in the treatment of chronic HCV/HBV coinfection. Recently, a limited study showed that IFN-α/ribavirin is effective for HCV clearance in IFN-naive HCV/HBV-coinfected patients [18]. Nevertheless, the response to IFN-α/ribavirin for previously IFN-relapsed HCV/HBV coinfection has not been evaluated. Suppression of one virus by another is usually present in the natural course of events in patients with HCV/HBV coinfection and is mostly dependent on the timing of virus introduction [3,5,19]. Reciprocal inhibitory effect of hepatitis viruses has been noted in clinical settings [10,20]. However, the dynamic and interaction between the two viruses after antiviral therapy remains not well known. We conducted a case-control study to investigate the efficacy of IFN-α/ribavirin combination therapy for IFN-naive and previously IFN-relapsed patients with HCV/HBV coinfection and to elucidate the interaction of these two viruses during and after antiviral therapy. Materials and methods Patients and case controls This study included 42 consecutive patients with chronic HCV/HBV coinfection, including 29 IFNnaive patients and 13 patients who relapsed after treatment with IFN-α monotherapy, recruited between May 1999 and April They were all seropositive for HCV antibodies (anti-hcv), HCV RNA and hepatitis B surface antigen (HBsAg) for more than 6 months. During the same period, 84 patients with CHC monoinfection, matched by sex, age and previous history of IFN-α therapy, were prospectively included as case controls in a ratio of 1:2 (58 IFN-naive and 26 IFN-relapsed patients). All controls were seropositive for anti-hcv and HCV RNA, and negative for HBsAg, for more than 6 months. All patients and controls had elevated serum alanine aminotransferase (ALT) levels and histologically proven chronic hepatitis. Patients with HIV or hepatitis delta virus infection, autoimmune hepatitis, primary biliary cirrhosis, sclerosing cholangitis, Wilson s disease, α 1 -antitrypsin deficiency, decompensated cirrhosis, overt hepatic failure, a current or past history of alcohol abuse ( 80 ml ethanol per day), a psychiatric condition or evidence of hepatocellular carcinoma were excluded. Other eligibility criteria included white blood cell count greater than /l, platelet count greater than /l, haemoglobin level greater than 12 g/dl, serum creatinine level less than 150 µmol/l, no pregnancy or lactation, and the use of a reliable method of contraception. The study was approved by the ethics committee of Kaohsiung Medical University Hospital and written, informed consent was obtained. Study design Improvement of efficacy on HCV clearance can be achieved with a higher dose and/or longer duration of IFN-α in CHC-monoinfected patients and in HCV/HBV-coinfected patients [2,11,16]. Due to the side effects suffered from long-term IFN-α therapy, we conducted the regimen with a higher dose of IFN-α (6 MU three-times weekly for 24 weeks) instead of the regimen with 3 MU three-times weekly for 48 weeks [16]. All patients received recombinant IFN-α-2b given intramuscularly, at a dose of 6 MU three times weekly for 24 weeks and mg of oral ribavirin daily in two divided doses during the periods of IFN-α therapy, with dose adjustment according to the degree of anaemia. Patients had biweekly outpatient visits during the first 4 weeks and monthly thereafter for 68 weeks. Liver function, complete blood count and serum levels of creatinine were evaluated at each visit. HBV serological markers, HCV RNA and HBV DNA were tested every 12 weeks for 72 weeks. A follow-up liver biopsy was advised at week 72. Initial and followup liver biopsy specimens were graded and staged according to the histological activity index [21] by a single pathologist, who was blinded to the treatment of each patient. Assessment of efficacy HCV SVR was defined as patients showing clearance of HCV RNA at the end of treatment and 48 weeks after the end of treatment. The others were classified as HCV non-svr. HBV SVR was defined as patients with baseline HBV viraemia showing clearance of HBV DNA at 24 and 48 weeks after the end of treatment. The others were classified as HBV non-svr. HBV DNA resurgence was defined as greater than two logs elevation of serum HBV DNA from baseline level on at least one occasion during treatment and the follow-up period. Sustained biochemical response was defined as persistence of normal serum ALT values up to 48 weeks after the end of treatment. Viral interaction between HBV and HCV was evaluated during treatment and follow-up periods. Tests for serological markers, HCV RNA and HBV DNA HBsAg, antibody to HBsAg (anti-hbs), HBeAg, anti- HBe and third-generation anti-hcv were detected with commercially available enzyme-linked immunosorbent assay kits (Abbott Laboratories, North Chicago, IL, USA). Detection of serum HCV RNA was performed using a standardized automated qualitative polymerase chain reaction (PCR) assay (Cobas Amplicor Hepatitis C Virus Test v2.0; Roche Diagnostics, Branchburg, NJ, USA; detection limit 50 IU/ml). HCV genotypes were determined by the method described by Okamoto et al. [22]. Serum HCV RNA levels were measured using the International Medical Press

3 HBV and HCV coinfection responses to IFN and ribavirin branched DNA assay (Versant HCV RNA 3.0; Bayer, Emeryville, CA, USA; quantification limit 615 IU/ml). Serum HBV DNA was determined by a standardized automated quantitative PCR assay (Cobas Amplicor HBV Monitor; Roche Diagnostics; detection limit 200 copies/ml). Statistical analyses Evaluation of efficacy of antiviral treatment was based on an intention-to-treat analysis. Frequency was compared between groups using the chi-square test with Yate s correction or Fisher s exact test. Group means were compared using the Analysis of Variance and Student s t-test. Serum HCV RNA and HBV DNA levels were expressed as the mean ± standard deviation after logarithmic transformation of original values. For the purpose of analysing the data with suitable statistical methods, we assigned a nominal value of 308 IU/ml to samples that were negative by the Versant HCV RNA 3.0 assay but positive for HCV RNA by qualitative PCR, a nominal value of 10 IU/ml to samples which were negative for HCV RNA by qualitative PCR, and a nominal value of 10 copies/ml to samples which were negative by Cobas Amplicor HBV Monitor assay. Stepwise logistic regression was used to analyse which variables had a better predictive value for SVR. Comparisons of paired liver histology were carried out with two-sample Wilcoxon s signed rank test. The procedures were performed by using the SPSS 8.0 statistical package (SPSS, Inc., Chicago, IL, USA). Results Demographic and clinical features of patients Table 1 summarizes the baseline demographic, clinical and virological characteristics of IFN-naive and IFNrelapsed chronic HCV/HBV-coinfected patients, and of IFN-naive and IFN-relapsed CHC controls. All characteristics were comparable among the four groups. IFN-α/ribavirin was discontinued due to adverse effects in one (3.4%) IFN-naive HCV/HBV-coinfected patient, two (3.4%) IFN-naive CHC controls and one (7.7%) IFN-relapsed CHC control. The rate of early withdrawal did not differ among the four groups. One IFN-naive HCV/HBV-coinfected patient discontinued IFN-α/ribavirin combination therapy and was lost to follow-up 7 months after enrolment. The incidence and severity of adverse events are similar among the four groups. HCV response and potential confounders Based on an intention-to-treat analysis, the rate of HCV SVR was 69.0% (20/29) and 69.2% (9/13) for IFN-naive and IFN-relapsed HCV/HBV-coinfected patients, respectively, compared with 67.2% (39/58) and 57.7% (15/26) for IFN-naive and IFN-relapsed CHC controls, respectively (Figure 1). The rate of HCV SVR did not differ among the four groups. We analysed factors associated with HCV SVR for 42 HCV/HBV-coinfected patients (Table 2). A significant negative association for HCV SVR was found for HCV genotype 1b. The independent predictive values Table 1. Basic demographic and clinical features of IFN-naive and IFN-relapsed HCV/HBV-coinfected patients compared with IFN-naive and IFN-relapsed CHC controls Interferon-naive Interferon-relapsed HCV/HBV-coinfected Chronic hepatitis C HCV/HBV-coinfected Chronic hepatitis C patients (n=29) patients (n=58) patients (n=13) patients (n=26) Age, years, mean ±SD 45.2 ± ± ± ±10.5 Sex, male/female 20/9 40/18 11/2 22/4 ALT, IU/l, mean ±SD 93.4 ± ± ± ±114.3 Liver histology Necroinflammatory activity, mean ±SD 4.6 ± ± ± ±2.2 Fibrosis score 3-4 (%) 11 (37.9) 12 (20.7) 3 (23.1) 5 (19.2) HCV RNA positivity (%) 29 (100) 58 (100) 13 (100) 26 (100) HCV genotype 1b (%) 14 (48.3) 31 (53.5) 7 (53.9) 17 (65.4) Baseline HCV viral load, log IU/ml, 5.40 ± ± ± ±0.99 mean ±SD HBeAg positivity (%) 2 (6.9) 0 (0) Anti-HBe positivity (%) 23 (79.3) 12 (92.3) HBV DNA positivity (%) 13 (44.8) 3 (23.1) Baseline HBV viral load (log equivalent/ml), mean ±SD 2.92 ± ±0.87 HBV, hepatitis B virus; HCV, hepatitis C virus; ALT, alanine aminotransferase; HBeAg, hepatitis B e antigen; SD, standard deviation. Antiviral Therapy 10:1 127

4 W-L Chuang et al. Figure 1. Sustained virological response of HCV in IFN-naive and IFN-relapsed HCV/HBV-coinfected patients compared with IFN-naive and IFN-relapsed CHC patients in an intention-to-treat analysis 100% 0% 69.0% 67.2% 20/29 39/58 IFN-naive 69.2% 57.7% IFNrelapsed HCV/HBV-coinfected patients CHC patients HCV, hepatitis C virus; HBV, hepatitis B virus. 69.1% 64.3% 9/13 15/26 29/42 54/84 Total of age, sex, history of previous IFN therapy, necroinflammatory activity and fibrosis of liver histopathology, pretreatment serum levels of ALT and HCV RNA, HCV genotype and presence of HBsAg for the achievement of HCV SVR for 126 CHC patients, with and without HBV coinfection, was determined by using multivariate logistic regression analysis. The significant factors associated HCV SVR were HCV genotype 1b, baseline HCV viral load and hepatic fibrosis score with odds ratios (95%CI) of ( ), ( ) and ( ), respectively. HBV response and potential confounders HBV SVR was achieved in five (31.3%) out of 16 baseline HBV viraemic patients. An inverse association for HBV SVR was found for HCV genotype non-1b (P<0.05, Table 3). Of five patients negative for both HBeAg and anti-hbe at enrolment, one had reappearance of serum HBeAg concomitant with resurgence of HBV DNA. The others remained negative for both HBeAg and anti-hbe throughout the treatment and follow-up periods. Of two patients positive for HBeAg and negative for anti-hbe at enrolment, one had anti- HBe seroconversion at week 72 concomitant with progressive decrease of serum HBV DNA. During long-term follow-up, disappearance of serum HBsAg was observed in six (14.3%) patients weeks after enrolment; five (11.9%) had concomitant anti- HBs seroconversion. Two of them were HCV non-responders and five were baseline HBV nonviraemic. All of the six patients had undetectable HBV DNA at week 72. Biochemical response Twenty-three (54.8%) of the 42 HCV/HBV-coinfected patients and 51 (60.7%) of the 84 CHC patients achieved biochemical sustained response. The biochemical response highly correlated to HCV SVR in both the HCV/HBV coinfection group (23/29, 79.3%, P<0.0001) and the CHC controls (50/54, 92.6%, P< ). In contrast, the biochemical response did not correlate to the seronegativity of HBV DNA at week 72 (11/24, 45.8%). Four patients had ALT flares after treatment. Of these, three were HCV nonresponders. The HBV DNA was undetectable during and after treatment. The remaining one, who was seropositive for baseline HBeAg and HBV DNA throughout the treatment and follow-up periods, was an HCV responder. All of the ALT flares were transient and no hepatic decompensation developed. Paired histological examination A follow-up liver biopsy was performed at week 72 in 23 HCV/HBV-coinfected patients and 52 CHC controls. In the follow-up biopsy of CHC controls, a histological improvement with a significant decrease in the mean scores of total necroinflammatory score was observed in both the patients with and without HCV SVR (SVR: 3.92 ±2.87 vs 1.46 ±1.85, P<0.0001; non- SVR: 4.27 ±2.22 vs 2.40 ±1.18, P<0.01, Wilcoxon s signed rank test). The improvement of fibrosis score was only observed in HCV responders (1.11 ±1.33 vs 0.89 ±1.31, P=0.06), and not in non-responders for CHC controls. In contrast, for HCV/HBV-coinfected patients, a significant improvement was observed only in the mean scores of total necroinflammatory score for HCV responders (4.53 ±2.45 vs 2.88 ±2.26, P=0.01), but not for non-responders. Neither the HCV responders nor the non-responders had improvement of fibrosis score in HCV/HBV-coinfected patients. Viral interaction between HBV and HCV The viral interaction between HBV and HCV in patients with and without HCV SVR is shown in Figure 2. For HCV responders, the serum level of HBV DNA returned to the baseline level at week 48 and week 72, accompanied with persistently undetectable HCV RNA. In contrast, for HCV non-responders, the serum level of HCV RNA returned to the pretreatment level at week 72, concomitant with persistently undetectable HBV DNA. With regard to the dynamics of serum HBV DNA between HCV sustained responders and non-responders, we observed that mean HBV loads declined during the treatment period in both of the groups. After the end of treatment, HBV DNA levels increased in HCV responders in contrast with persistently decreasing in HCV non-responders. The serum levels of HBV DNA did not differ between the International Medical Press

5 HBV and HCV coinfection responses to IFN and ribavirin Table 2. Factors associated with HCV SVR to IFN-α/ribavirin combination therapy in chronic HCV/HBV-coinfected patients Total, n HCV non-svr, n (%) HCV SVR, n (%) P value Patient number (31.0) 29 (69.1) Gender Male (32.3) 21 (67.7) Female 11 3 (27.3) 8 (72.7) Age, years 45.8 ± ±9.0 Previous interferon therapy No 29 9 (31.0) 20 (69.0) Yes 13 4 (30.8) 9 (69.2) Liver histopathology Total score of necroinflammatory activity 4.08 ± ±2.09 Fibrosis score F (32.1) 19 (67.9) F (28.6) 10 (71.4) Pretreatment ALT value, IU/l 88.0 ± ±76.0 Pretreatment serum level of HCV RNA, log IU/ml 5.69 ± ± HCV genotype 1b (52.4) 10 (47.6) <0.01 Non-1b 21 2 (9.5) 19 (90.5) Pretreatment serum level of HBV DNA, log eq/ml 1.54 ± ± Pretreatment serum level of HBV DNA Negative by PCR 26 9 (34.6) 17 (65.4) Positive by PCR 16 4 (25.0) 12 (75.0) Pretreatment serum level of HBV DNA Below eq/ml (35.1) 24 (64.9) 0.14 Above eq/ml (100) Pretreatment HBeAg Negative (32.5) 27 (67.5) Positive (100) HCV, hepatitis C virus; HBV, hepatitis B virus; SVR, sustained virological response; ALT, alanine aminotransferase; eq, equivalent; PCR, polymerase chain reaction; HBeAg, hepatitis B e antigen. two groups at enrolment and at the end of treatment. The serum levels of HBV DNA were significantly higher in HCV responders than in HCV non-responders at both week 48 and week 72 (2.99 ±2.50 vs 1.00 ±0.00 and 2.99 ±2.01 vs 1.00 ±0.00; P<0.01 and P<0.002, respectively). For baseline HBV and HCV viraemic patients, HBV SVR was achieved in all four HCV non-responders, which was significantly higher than those with HCV SVR (8.3%, 1/12, P<0.01; Table 4). Only one patient had concomitant HCV and HBV SVRs. For baseline HBV non-viraemic patients, reappearance of serum HBV DNA was observed in one (12.5%) out of eight HCV non-responders, which was significantly fewer than HCV responders (58.8%, 10/17, P<0.05). Altogether, HBV DNA resurgence was noted in 44.8% (13/29) of HCV responders, which was significantly more frequent than that in HCV non-responders (8.3%, 1/12, P<0.05). Of 13 HCV responders with HBV DNA resurgence, six had a decline of serum HBV DNA to pretreatment levels at week 72. Similarly, the resurgence of HBV DNA was transient for the HCV non-responders. No icteric hepatitis developed in patients with HBV resurgence. Discussion We demonstrate that IFN-α at a dose of 6 MU threetimes weekly and ribavirin combination therapy for 24 weeks in patients with chronic HCV/HBV coinfection is as effective, safe and well tolerated as in patients with CHC monoinfection, whether IFN-naive or previously IFN-relapsed. A total of 69% of HCV/HBV-coinfected patients could clear serum HCV RNA and 54% had sustained normalization of ALT. Disappearance of HBV DNA was observed in 31% of HBV viraemic patients. Loss of HBsAg accompanied by anti-hbs seroconversion was attained in 12% of HCV/HBV-coinfected patients in long-term follow-up. There is a mutual viral response of HCV and HBV to antiviral therapy. Reciprocal interaction between HCV and HBV was noticed after antiviral therapy. Antiviral Therapy 10:1 129

6 W-L Chuang et al. Table 3. Factors associated with HBV SVR to IFN-α/ribavirin combination therapy in chronic HCV/HBV-coinfected patients with both HCV and HBV viraemia Total, n HBV non-svr, n (%) HBV SVR, n (%) P value Patient number (31.3) 5 (68.8) Gender Male (78.6) 3 (21.4) Female (100) Age, years 43.2 ± ±12.9 Previous interferon therapy No 13 9 (69.2) 4 (30.8) Yes 3 2 (66.7) 1 (33.3) Liver histopathology Total score of necroinflammatory activity 4.64 ± ±2.83 Fibrosis score F (63.6) 4 (36.4) F (80.0) 1 (20.0) Pretreatment ALT value, IU/l 67.4 ± ±11.3 Pretreatment serum level of HCV RNA, log IU/ml 5.28 ± ±0.76 HCV genotype 1b 6 2 (33.3) 4 (66.7) <0.05 Non-1b 10 9 (90.0) 1 (10.0) Pretreatment serum level of HBV DNA, log eq/ml 5.04 ± ±2.80 Pretreatment serum level of HBV DNA Below eq/ml 11 7 (63.6) 4 (36.4) Above eq/ml 5 4 (80.0) 1 (20.0) Pretreatment HBeAg Negative 14 9 (64.3) 5 (35.7) Positive 2 2 (100) 0 HCV, hepatitis C virus; HBV, hepatitis B virus; SVR, sustained virological response; ALT, alanine aminotransferase; eq, equivalent; HBeAg, hepatitis B e antigen. In the present study, improvement of HCV SVR by the use of IFN-α/ribavirin combination therapy was observed not only in IFN-naive and IFN-relapsed CHC-monoinfected patients [2,13,14,16] but also in IFN-naive and IFN-relapsed chronic HCV/HBVcoinfected patients, when compared with those treated with IFN-α monotherapy [5,8,9,11]. As reported in CHC patients [2,23], our results show that HCV genotype 1b, high baseline viral load and hepatic fibrosis remain the major factors associated with lower HCV response in HCV/HBV-coinfected patients. Similarly to CHC-monoinfected patients, 90% of HCV/HBVcoinfected patients with genotype non-1b could achieve an HCV SVR, in contrast with less than 50% of those with genotype 1b responding to the present regimen. Recently, a combination of pegylated IFN-α plus ribavirin proved to be more effective and convenient and may replace the current standard of IFN-α plus ribavirin [24,25]. A 48-week course of pegylated IFN-α/ribavirin combination therapy has been shown to yield a better efficacy in the achievement of SVR in patients with genotype 1 than a 24-week combination therapy [26]. Further studies on future therapeutic strategies of individualizing dose and duration of standard or pegylated IFN-α treatment in combination with ribavirin according to the baseline virological predictors to improve the efficiency of HCV eradication are needed for chronic HCV/HBV-coinfected patients, as recommended in recent consensus on management of CHC [15,26,27]. Consistent with a previous report [18], approximately one-third of HBV viraemic HCV/HBVcoinfected patients had HBV SVR in our study. Interestingly, patients with HCV genotype non-1b had significantly lower HBV response than those with genotype 1b. Two possibilities are suggested in the clinical setting. Firstly, there is an HCV genotype-specific difference in the viral interaction between HCV and HBV in that HBV replication was inhibited more efficiently by HCV genotype 1 than by genotype 2 [10], resulting in different HBV response to IFN-based therapy between patients coinfected with different HCV genotypes. Secondly, the HCV genotype is a confounding factor for HBV response, because HCV genotype non-1b had a greater response to antiviral therapy and HCV responders had significantly lower HBV response (Table 4) International Medical Press

7 HBV and HCV coinfection responses to IFN and ribavirin Figure 2. Dynamics of serum HCV RNA and HBV DNA during and after interferon/ribavirin combination therapy in (A) HCV/HBVcoinfected patients with HCV sustained virological response and (B) in patients without HCV SVR A B Dynamics of HCV RNA, log IU/ml Baseline Week 24 (EOT) Week 48 HCV RNA HBV DNA Week Dynamics of HBV DNA, log equivalent/ml Dynamics of HCV RNA, log IU/ml Baseline Week 24 (EOT) Week 48 HCV RNA HBV DNA Week Dynamics of HBV DNA, log equivalent/ml Weeks after enrolment Weeks after enrolment HCV, hepatitis C virus; HBV, hepatitis B virus; EOT, end of treatment. It is worth noting that disappearance of HBsAg concomitant with anti-hbs seroconversion developed in five (11.9%) HCV/HBV-coinfected patients. This was not observed in previous studies on IFN/ribavirin combination therapy for Western and Asian CHB patients with and without HCV coinfection [17,18]. Loss of HBsAg with anti-hbs seroconversion is not infrequent in Caucasian patients with IFN-based therapy [6], but it is very rare in the Asian population [28] because HBV infection is usually acquired perinatally or in early childhood. Superinfection of HCV may enhance seroclearance of HBV antigens [3,5]. Our results suggest that IFN-α/ribavirin could enhance the clearance of serum HBV DNA and HBsAg with anti- HBs seroconversion in chronic HCV/HBV coinfection. The natural course of dual or triple hepatitis virus infections is associated with viral interference. Mostly, HCV exerts a suppressive effect on HBV and HDV and may enhance seroclearance of HBV antigens or even replace the pre-existing virus as the agent for continuing hepatitis [3,5,20]. As the newcomer, HBV may also suppress the pre-existing HCV [19]. The timing or sequence of infection is thus a factor influencing the outcome of viral interactions. However, the viral dynamic during and after antiviral treatment in dual hepatitis virus infections has not been well studied before. Our results showed that both HBV and HCV viral loads were suppressed during and at the end of treatment in most HCV/HBV-coinfected patients. After the end of treatment, HBV DNA remained persistently undetectable in HCV non-responders, in contrast with serum HBV DNA returning to pretreatment levels in HCV responders. HBV reactivation following the clearance of HCV may be responsible for the elevated Table 4. Viral interaction of HBV and HCV in HCV/HBV-coinfected patients HBV response in HBV DNA reappearance HBV DNA resurgence 16 baseline HBV in 25 baseline HBV in 42 HCV/HBVviraemic patients non-viraemic patients coinfected patients HCV response Non-SVR SVR Yes No Yes No Non-SVR, n (%) 0 4 (100) 1 (12.5) 7 (87.5) 1 (8.3) 11 (91.7) SVR, n (%) 11 (91.7) 1 (8.3) 10 (58.8) 7 (41.2) 13 (44.8) 16 (55.2) P value <0.01 <0.05 <0.05 HBV DNA resurgence: >2 logs elevation of serum HBV DNA at least one occasion during treatment and follow-up period. HCV, hepatitis C virus; HBV, hepatitis B virus; SVR, sustained virological response. Antiviral Therapy 10:1 131

8 W-L Chuang et al. ALT levels after the end of treatment in one-fifth of HCV responders [18,29]. This implies that reciprocal viral interaction remains present after antiviral treatment in dual hepatitis virus infections. HCV is usually the dominant virus for continuing hepatitis in Taiwanese patients with HCV/HBV coinfection [5]. Our results indicate that HBV reactivation following seroclearance of HCV by antiviral treatment could change the situation. The mechanism by which reciprocal interference of virus replication occurs remains speculative. Previous data indicated that HCV core protein has an effect on transcription from HBV DNA, probably mediated by the two HBV enhancers 1 and 2 [30,31]. Evidence at the molecular level shows that sequence similarities between an arginine-rich nucleocapsid motif of both viruses could support the reciprocal interference of virus replication and the extent of interference is influenced by the infecting HCV genotype [10,31]. HBV reactivation flares occur in 19 50% of CHB patients after stopping antiviral therapy, some of whom develop liver decompensation and die [32]. Resurgence of HBV DNA is not infrequent in our HCV/HBV-coinfected patients, especially in the HCV responders. This raises the concern that severe hepatitis and/or hepatic failure may follow HBV reactivation after antiviral treatment in chronic HCV/HBV-coinfected patients [29,33]. However, only one case out of four HCV/HBV-coinfected patients developing ALT flares after the end of treatment was related to active HBV replication. No icteric hepatitis flare was noted in our patients and most of the HBV resurgence was transient. Nevertheless, careful monitoring in chronic HCV/HBV-coinfected patients with antiviral therapy should be considered. Surprisingly, seroclearance of either HBV or HCV is achieved in all 16 patients with baseline HBV and HCV viraemia (Table 4), emphasizing the antiviral effect of IFN-α/ribavirin on both viruses. However, only one (8.3%) had simultaneous eradication of HBV and HCV and the HBV SVR correlated negatively to HCV SVR, suggesting that there might be a mutual viral response to antiviral therapy in HCV/HBV coinfection. Two explanations might be attributed to this phenomenon. Firstly, HCV genotype 1b, which is more resistant to IFN-based therapy [2,23], has more efficient inhibition on HBV replication in HCV/HBV coinfection [10,31]. This may enhance and promote the HBV response to IFN-α/ribavirin [6]. Therefore the HCV non-responders, mostly with HCV genotype 1b infection, had higher HBV SVRs. Secondly, there is a reciprocal viral interaction between HBV and HCV [3,5,19,20]. For HCV non-responders, the HBV replication remained inhibited after IFN-α/ribavirin therapy, resulting in persistently undetectable HBV DNA. Further studies with larger numbers of patients are necessary to address the mechanism of mutual viral response to antiviral therapy. 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