Patterns of viral decline during PEG-interferon alpha-2b therapy in HBeAg-positive chronic hepatitis B: Relation to treatment response
Hepatology Aug 29, 2006
Volume 44, Issue 3, Pages 721-727
Martijn J. ter Borg 1, Monika van Zonneveld 1, Stefan Zeuzem 2, Hakan Senturk 3, Ulus S. Akarca 4, Christopher Simon 5, Bettina E. Hansen 1 6, Bart L. Haagmans 7, Robert A. de Man 1, Solko W. Schalm 1, Harry L.A. Janssen 1 *, HBV 99-01 Study Group
1Department of Gastroenterology and Hepatology, Erasmus Medical Center Rotterdam, The Netherlands
2Medizinische Klinik und Poliklinik, Innere Medizin II, Universitatskliniken des Saarlandes, Homburg/Saar, Germany
3Department of Internal Medicine, Cerraphasa Medical Faculty, University of Istanbul, Istanbul, Turkey
4Department of Gastroenterology, Ege University Hospital, Izmir, Turkey
5Department and Clinic of Infectious Diseases, Medical University, Wroclaw, Poland
6Department of Epidemiology and Biostatistics, Erasmus Medical Center Rotterdam, The Netherlands
7Department of Virology, Erasmus Medical Center Rotterdam, The Netherlands
...To evaluate whether viral decline during therapy can predict a sustained off-treatment response (HBeAg loss) we analyzed viral decline in HBeAg-positive chronic hepatitis B patients treated with pegylated interferon alpha-2b (PEG-IFN) alone or in combination with lamivudine....
....In conclusion, combination therapy with PEG-IFN and lamivudine is more effective in suppressing HBV replication than PEG-IFN alone during treatment. However, this did not result in enhanced response (HBeAg loss) at the end of follow-up. Different patterns of viral decline during PEG-IFN monotherapy could be identified: a delayed decline pattern was associated with the highest HBeAg- and HBsAg loss. Furthermore, viral decline in responders and non-responders were different across HBV genotypes during PEG-IFN monotherapy. To reduce unnecessary prolonged exposure to costly and toxic PEG-IFN stopping rules are needed. In our population, such a stopping rule could only be retrieved for patients harboring genotype A. In those patients one log HBV DNA decline after 32 weeks of PEG-IFN monotherapy was a satisfactory predictor for sustained off-treatment response. This stopping rule needs to be validated in other studies.
Nucleos(t)ide analogues, such as lamivudine or adefovir dipivoxil strongly suppress viral replication and induce hepatitis B e antigen (HBeAg) loss in 12% to 33% of the patients.[1-5] However, the response of these agents may not be durable after discontinuation of therapy and prolonged therapy leads to the emergence of resistant hepatitis B virus (HBV) mutants in an increasing proportion of patients.[6-10]
Interferon alpha (IFN) has been shown to induce HBeAg seroconversion in approximately one third of patients, but has considerable side effects. The efficacy of IFN therapy is improved by using its pegylated form, resulting in higher response rates in patients with chronic hepatitis B.[12-15] The most important predictive baseline factors for response to pegylated interferon therapy are HBV genotype A or B, low HBV DNA and elevated alanine aminotransferase (ALT) levels. In the current consensus statements for the management of chronic hepatitis C stopping rules are used according to early viral decline. Until now, there are no stopping rules used in the management of chronic hepatitis B. The side effects and costs associated with the treatment of pegylated interferon make it worthwhile to investigate the possibility of a model to predict non-response at an early stage of treatment.
In chronic hepatitis B, it is difficult to predict an early therapeutic response. We investigated the viral decline during therapy with pegylated interferon alpha-2b (PEG-IFN) with or without lamivudine in 266 HBeAg-positive chronic hepatitis B patients.
In patients treated with PEG-IFN and lamivudine, a uniform biphasic viral decline pattern was found during therapy and there were no marked differences in viral load between those who lost HBeAg at the end of follow-up (response) or not.
In contrast, those treated with PEG-IFN monotherapy exhibited different viral decline patterns.
A delayed decline of at least two log from baseline HBV DNA after week 4 but before week 32 was associated with the highest response rate (63%).
In comparison, response was 52% for patients with an early decline (week 0-4), 38% for a late decline (week 32-52), 27% for a posttreatment decline (week 52-78) and 11% for patients with no substantial decline.
The HBsAg loss was 22% in the delayed decline pattern compared to 4% for those with early decline and none for other decline patterns.
In conclusion, different patterns of decline in viral load during treatment with PEG-IFN monotherapy were associated with different rates of HBeAg and HBsAg loss at the end of follow-up.
Since there was a considerable response, even in patients with a late or posttreatment decline pattern, prediction of response based on viral decline during the first months of therapy was difficult.
Patient characteristics have been previously described in detail. In short, 205 men (77%) and 61 women (23%) with a mean age of 35 ± 13 years were included. Ninety patients (34%) had genotype A, 23 (9%) genotype B, 39 (15%) genotype C, 103 (38%) genotype D, and eleven patients (4%) had other genotypes. The PEG-IFN monotherapy and PEG-IFN/lamivudine combination therapy groups were comparable with respect to all baseline parameters. HBeAg loss at the end of follow-up (response) was achieved in 36% of the PEG-IFN monotherapy therapy group and 35% of the combination group (P = .91). Of the 95 patients who lost HBeAg at the end of follow-up, 77 (81%) patients were also anti-HBe positive. This was 80% in the PEG-IFN monotherapy group and 83% in the combination therapy group. HBsAg loss was achieved in 9 patients (7%) of the PEG-IFN monotherapy group and in 9 patients (7%) of the combination group (P .92). Sixteen out of those 18 patients (89%) with HBsAg loss were also anti-HBs positive. Fifty-five patients (21%) had been treated previously with standard IFN, and 33 patients (12%) with lamivudine. In patients previously treated with IFN, 25% responded; in the treatment naive population the response rate was 39% (P = .17).
Viral Dynamics in PEG-IFN Monotherapy or Combined With Lamivudine.
The decline of HBV DNA during PEG-IFN monotherapy and combination therapy is shown in Fig. 1A. In the PEG-IFN monotherapy group, HBV DNA decline after 52 weeks was 2.27 ± 2.32 log; in the combination therapy group HBV DNA decline after 52 weeks was 5.34 ± 2.18 log. In individual patients, the decline of HBV DNA during monotherapy with PEG-IFN treatment and follow-up had a variable pattern whereas nearly all patients in the combination therapy group showed a biphasic decline pattern during treatment. HBV DNA decline was significantly slower in the monotherapy group than in the combination therapy group during the first 16 weeks (P < .01). Patients in the combination therapy group had significantly lower mean HBV DNA levels at all time points during therapy. Due to a relapse in HBV DNA during follow-up in the combination therapy group HBV DNA levels became comparable for both treatment groups at the end of follow-up (Fig. 1A).
In the combination treatment group, viral decline after 16 weeks was 5.06 ± 1.27 log for responders (HBeAg loss at the end of follow-up) and 4.44 ± 1.22 log for non-responders (P = .01). The large overlap in viral load reduction between responders and non-responders (0.62 log) precluded the use of on-treatment HBV DNA decline as a predictor for HBeAg loss to combination therapy. In contrast, in the PEG-IFN monotherapy group marked differences in viral decline between responders and non-responders were observed. The HBV DNA decline after 16 weeks was 2.26 ± 2.11 log for responders and 0.89 ± 1.03 log for non-responders (P < .001) (Fig. 1B-C).
Different Patterns of Viral Decline in PEG-IFN Monotherapy.
To investigate whether response could be predicted at an early time point during monotherapy with PEG-IFN (n = 136), HBV DNA decline from baseline to week 4, 16 and 32 were assessed as possible predictors of response. In this group of patients, the areas under the ROC curve for week 4, 16 and 32 were 0.63, 0.70 and 0.80, respectively. Response could be predicted best by a 1-log HBV DNA decline at week 32 of therapy, which included 82% of responders but excluded only 64% of the non-responders. The positive and negative predictive values were not more than 58% and 86%, respectively.
Patterns of Viral Decline.
We analyzed the different patterns of viral decline in patients treated with PEG-IFN monotherapy. A specific predefined pattern of viral decline could be assessed in 123 patients; 11 patients discontinued the therapy early due to side effects and of two patients insufficient HBV DNA measurements were available to assess HBV DNA decline patterns. According to earlier studies on viral kinetics we used week 4 as cutoff for early decline. Five different patterns of viral decline could be recognized: I. early decline defined as more than 1 log reduction in HBV DNA during week 0-4 of therapy (n = 23); II. delayed decline of at least 2 log from baseline HBV DNA during week 4-32 without early decline (n = 32); III. late decline of at least 2 log from baseline HBV DNA between week 32 and 52 without previous decline patterns (n = 13); IV. posttreatment decline of 2 log from baseline HBV DNA after week 52 without previous decline patterns (n = 11); V. no substantial decline at any time point (n = 44). Figure 2 shows the longitudinal HBV DNA reduction and the percentages of HBeAg (response) and HBsAg loss at the end of follow-up for each decline pattern. Response rate was 52% for patients with an early decline, 63% for a delayed decline, 38% for a late decline, 27% for a post-treatment decline and 11% for patients with no substantial decline. The difference in HBeAg loss among patients with an early or delayed decline compared to patients with a late, posttreatment or no decline pattern was significant (P = .001). Among the patients with a delayed decline (n = 32), 14 (44%) patients had genotype A, 2 (6%) genotype B, 4 (13%) genotype C and 10 (31%) genotype D. These differences were not significant, particularly because of the limited number of patients with HBV genotype B and C. During treatment and follow-up, 37 patients exhibited ALT flares, defined as a threefold increase in serum ALT compared with baseline levels. There was a clear and nearly significant difference in the amount of ALT flares between patients with a delayed decline (41%) and those with no decline (20%) (P = .056). ALT flares occurred in 17% of the patients with an early decline, in 23% of the patients with a late decline and in 18% of the patients with a posttreatment decline. In the group of patients with a delayed viral decline, the high HBeAg response was accompanied by a substantial loss of HBsAg (22%) and reduction of HBV DNA below 400 copies/mL (25%). In fact, 7 of 8 patients (88%) with HBsAg loss and all patients with HBV DNA below 400 copies/ml at the end of follow-up (n = 8) exhibited a delayed decline pattern. Only one patient with early viral decline and none with late or posttreatment decline became serum HBsAg negative.
Relation Between Viral Dynamics and Response in Different Hepatitis B Virus Genotypes
In patients treated with PEG-IFN monotherapy, marked differences were found between responders and non-responders according to HBV genotype (Fig. 3). For patients with genotype A (n = 47), responders had a pronounced decline of HBV DNA whereas non-responders remained flat during the treatment period and follow-up. In contrast to other HBV genotypes, a 1 log decline of HBV DNA at week 32 of treatment was highly predictive for response in genotype A; the area under the ROC curve was 0.96, with a sensitivity of 94%, a specificity of 92%, a positive predictive value of 89% and a negative predictive value of 96%. Using this 1 log HBV DNA decline at week 32 as a stopping rule would thus lead to exclusion of 4% of potential sustained responders.
In the other genotypes, i.e. B (n = 12), C (n=21) and D (n = 51), both responders and non-responders showed an on-treatment decline in HBV DNA, which persisted posttreatment only in responders (Fig. 3). The area under the ROC curve for a 1 log decline at week 32 was 0.83, 0.71 and 0.59, respectively for genotypes B, C and D. Five patients with other genotypes were not analyzed.
In the present study, different patterns of viral decline in 266 HBeAg-positive chronic hepatitis B patients were analyzed during treatment with pegylated interferon alpha-2b with or without lamivudine. HBV DNA showed a biphasic decline in the combination therapy group, as has previously been described for nucleoside analogues in chronic hepatitis B.[24-28] For PEG-IFN monotherapy we found significantly less decline of HBV DNA throughout the treatment period as compared to combination therapy. Despite these differences in HBV DNA decline, loss of HBeAg and HBsAg at the end of follow-up were similar in both treatment groups. We observed a pronounced HBV DNA relapse during posttreatment follow-up in the combination therapy group.
Patients with a delayed HBV DNA decline (>2 log HBV DNA decline between week 4 and 32) rather than those with an early HBV DNA decline, had the highest chance of response at the end of follow-up. Moreover, nearly all patients who became HBsAg negative (7 of 8; 88%) or HBV DNA negative by PCR (8 of 8; 100%) exhibited a delayed viral decline pattern. Both these findings suggest that early and vigorous suppression of HBV DNA is not always sufficient to tip the balance in favor of the host's immune response. It is assumed that an immunomodulatory effect of PEG-IFN rather than its direct antiviral effect leads to a sustained off-treatment response with high chances of HBsAg seroconversion after a long-term follow-up. In the delayed viral decline pattern, one could hypothesize that moderate viral decline in the first month of therapy reflects the direct but partial antiviral effect of PEG-IFN, whereas the strong viral load reduction thereafter is induced by a combined immunomodulatory and antiviral effect.
Patients with a late decline pattern between weeks 32-52 of treatment or even a posttreatment decline still had a considerable chance (31% and 27%, respectively) to lose HBeAg. It thus remains difficult to establish a good predictor of response early during PEG-IFN treatment in our total chronic hepatitis B population. This concurs with other studies on IFN or PEG-IFN treatment where primarily baseline factors (low viral load and high ALT) but not on-treatment factors could predict treatment response.
When analyzing the results according to HBV genotype we found that only for genotype A viral decline of responders (defined as HBeAg negative at the end of follow-up) and non-responders diverged apparently during early PEG-IFN monotherapy. Responders showed a pronounced decline in HBV DNA compared to non-responders. Therefore, in genotype A response could be predicted by a 1 log HBV DNA decline at week 32 with a high sensitivity and specificity. Earlier predictions were less accurate and not sufficient to be used in clinical practice. In patients with genotype B, C and D, both responders and non-responders show a decline in HBV DNA during PEG-IFN treatment. This precluded response prediction. However, this stopping rule was based on a relatively small number of patients and it may not work with pegylated interferon alpha-2a or with pegylated interferon alpha-2b at a different or constant dose, therefore it needs to be validated in other studies.
Although this study is the first to describe that prediction of response in patients with chronic HBeAg-positive hepatitis B treated with PEG-IFN is possible, there are two limitations. First, a relatively small number of patients with genotypes B and C were included in our study. Second, after 32 weeks a dose reduction of PEG-IFN from 100 g to 50 g once weekly was scheduled to limit early treatment discontinuation. This dose reduction could have led to suboptimal response and thus influence response prediction based on viral dynamics.
Recently, for patients treated with pegylated interferon alpha-2a sustained response could not be predicted sufficiently on the basis of viral decline during therapy. Farci et al. studied on-treatment predictors for sustained response in HBeAg-negative chronic hepatitis B treated with pegylated interferon alpha-2a. They found a 1 log drop in HBV DNA or HBV DNA reduction below 7 log by week 12 of some predictive value for response and concluded that these data are insufficient to be used as a stopping rule. In this study with pegylated interferon alpha-2a, the number of patients with genotype A was small.
In conclusion, combination therapy with PEG-IFN and lamivudine is more effective in suppressing HBV replication than PEG-IFN alone during treatment. However, this did not result in enhanced response (HBeAg loss) at the end of follow-up. Different patterns of viral decline during PEG-IFN monotherapy could be identified: a delayed decline pattern was associated with the highest HBeAg- and HBsAg loss. Furthermore, viral decline in responders and non-responders were different across HBV genotypes during PEG-IFN monotherapy. To reduce unnecessary prolonged exposure to costly and toxic PEG-IFN stopping rules are needed. In our population, such a stopping rule could only be retrieved for patients harboring genotype A. In those patients one log HBV DNA decline after 32 weeks of PEG-IFN monotherapy was a satisfactory predictor for sustained off-treatment response. This stopping rule needs to be validated in other studies.
Patients and Methods
A total of 266 patients were evaluated in an international multicenter randomized double-blinded study previously reported. The study was conducted in accordance with good clinical practice and the Declaration of Helsinki, and it was formally approved by the ethics committee of each participating center. Detailed and exclusion criteria are also reported elsewhere. Eligible patients were men and women over 16 years of age with HBeAg-positive chronic hepatitis B. All patients were HBV DNA positive (above 105 copies/mL) and had ALT levels of at least 2 times the upper limit of normal on two occasions within eight weeks before randomization.
Patients received pegylated interferon alpha-2b (PegIntron, Schering-Plough, Kenilworth, NJ) 100 g once weekly and were randomized to receive either lamivudine 100 mg once daily or placebo. The dose of PEG-IFN was reduced to 50 g once weekly after 32 weeks of therapy. Patients were treated for 52 weeks and followed for 26 weeks posttreatment. Serum samples for HBV DNA measurement were taken at the start of therapy, and monthly thereafter until the end of follow-up. HBV DNA levels were measured using an in-house developed TaqMan real-time PCR assay (dynamic range 4X102-1010 copies/mL). The Eurohep HBV DNA standard was used for validation of HBV DNA levels. The assessment of HBV genotypes was done by Inno-Lipa assay (Innogenetics, Ghent, Belgium). Hepatitis B surface antigen (HBsAg), HBeAg, antibodies to hepatitis B surface (anti-HBs) and e antigen (anti-HBe) were measured using a commercially available immunoassay (Abbott Laboratories, Abbott Park, Il). Response was defined as serum HBeAg negativity at the end of follow-up.
Comparisons between groups were done using the chi-square test or Fisher's exact test for categorical variables, and the Mann-Whitney test for continuous variables. To investigate whether response could be predicted during therapy, HBV DNA decline from baseline to the time points week 4, week 16 and week 32 were assessed as possible predictors of response. For each test, areas under the receiver operating characteristic (ROC) curves were calculated and compared. Also for each time point, different levels (in half-log steps) of HBV DNA decline from baseline were assessed to determine which cut-off level best excluded patients who failed to respond. All data were analyzed using SPSS (version 12.0.1 SPSS Inc., Chicago, IL). Where appropriate, mean values are given ± standard deviation. All tests for significance and resulting P values were two-sided, with a level of significance of .05.