- Email: [email protected]
Long-term efficacy of treatment of chronic hepatitis C with alpha interferon or alpha interferon and ribavirin
Journal of Hepatology 1999: 31: (Suppl.1): 244249 Printed in Denmark . All rights reserved Munksgaard Copenhagen
Copyright 0 European Association for the Study of the Liver 1999 Journal of Hepatology
ISSN 01694185 ISBN 87-16-16386-9
Long-term efficacy of treatment of chronic hepatitis C with alpha interferon or alpha interferon and ribavirin Eleanor
Barnes, George Webster, Ruth Jacobs and Geoffrey
Dusheiko
Department of Medicine, Royal Free and University College School of Medicine, London, United Kingdom
The major objective of treatment of chronic hepatitis C virus (HCV) infection is to prevent progression to cirrhosis, and thereby prevent complications of end-stage liver disease. The established treatment of chronic HCV is with alpha interferon. Recent results with ribavirin and alpha interferon together suggest that combination antiviral therapy will become the benchmark treatment. For both naive and relapsed patients, however, it has become important to assess the long-term outcome of treatment, in order to gauge whether treatment has indeed modified the natural history of chronic
hepatitis C virus infection. It seems likely that most sustained responders (85-W”/) treated with combination ribavirin and alpha interferon will continue to have a long-term biochemical and virological response, as has been demonstrated with alpha interferon alone, but further long-term follow-up of patients treated with combination therapy is required.
MAJORobjective of treatment of chronic hepatitis C virus (HCV) infection is to prevent progression to cirrhosis, and thereby prevent the complications of end-stage liver disease. The established treatment of chronic HCV is with alpha interferon. Recent results with ribavirin and alpha interferon together suggest that combination antiviral therapy will become the benchmark treatment. Earlier trials with alpha interferon monotherapy for both 6 and 12 months of treatment indicated the tendency of patients to relapse after an initial biochemical response to alpha interferon therapy. Combination therapy with alpha interferon and ribavirin therapy has proven superior to retreatment with alpha interferon monotherapy in patients who have relapsed after alpha interferon monotherapy, and to treatment with alpha interferon in naive patients. For both naive and relapsed patients, however, it has become important to assess the long-term outcome of treatment, in order to gauge whether treatment has indeed modified the natural history of chronic hepatitis C virus infection. This data has not
been easy to obtain, and surrogate markers are being used to assess disease outcome.
T”
Correspondence: Professor G. Dusheiko, Dept of Medicine, Royal Free and University College School of Medicine, Pond Street, Hampstead, London NW3 2QG, UK. Tel: + 44 171 830 2993. Fax: + 44 171 431 4581. e-mail: [email protected]
244
Key words: Alpha interferon; Antiviral response; Antiviral therapy; Chronic hepatitis C: Ribavirin.
Definition of long-term response Long-term response must be defined. The term is a relative one and the duration of follow-up to clearly define a “long-term” response has not been established. By convention, the primary outcome measure in several controlled trials has been the normalisation of serum ALT and AST 6 months after stopping treatment, defined as a sustained biochemical response. A second outcome measure has been negative serum HCV RNA, measured by PCR, 6 months after stopping treatment (defined as a sustained virological response). Histological assessment has been included as a primary or secondary outcome measure in several studies. Assessment of LTR requires a precise definition of the end-of-treatment response, and sustained response, as the long-term durability of a sustained virological response probably depends upon the absence of detectable HCV RNA 6 months after stopping treatment. Thus the sensitivity of HCV RNA measurement in serum by PCR could affect results, in the same way that the sensitivity and specificity of HCV RNA tests would affect the predictive value of a negative HCV RNA at the end of treatment and follow-up. Unfortunately, HCV RNA measurement remains poorly
Chronic HCV treatment
End of treatment Sustained Long term
ALT
HCV RNA
I-
6-12 Months
-I
6
Histological
Fig. 1. Dejinitions of response.
standardised. Likewise, quantitation and interpretation of histological response will also require further technical development, in order to interpret the consequences of apparently favourable antiviral therapy. Assessment of histological response will depend upon the development of acceptable scoring systems to measure necroinflammatory parameters and fibrosis. The sensitivity and agreement of measures of hepatocellular damage have not been confirmed. The definitions of tissue inflammation and necrosis are not stringent, and are subject to observer and sampling error. Also, patients are often not biopsied years after stopping therapy, and only a few studies have addressed the important question of long-term histological improvement. Other parameters might be able to be used to assess long-term response and disease modification. These could include measurement of HCV RNA in liver tissue, HCV antigens in liver tissue, serum markers of fibrosis, possibly seroreversion to negative anti-HCV,
or a decrease in titres and even disappearance of antiE2 antibodies. An assessment of symptoms and improvement in the quality of life is feasible after an apparent antiviral response. Studies to determine whether there is a reduced progression of liver disease to decompensation, hepatocellular failure, liver transplantation or the development of hepatocellular carcinoma will be important, particularly in patients with established or advanced fibrosis prior to antiviral treatment (1, 2).
Long-term response data for alpha interferon monotherapy Biochemicallvirological response
There is relatively little data concerning LTR in patients with a sustained response to alpha interferon monotherapy. In general, these studies have followed patients for varying lengths of time but in some cases for several years. The definition of sustained response
TABLE 1 Long-term response (LTR) in patients with sustained response (SR) to alpha interferon monotherapy Author
n
Sustained response
Definition sustained response
Follow-up (years)
Mean follow-up
Normal ALT
Negative HCV RNA
Reichard 1999 Lau et al. (7) Camma et al. (8) Marcellin et al. (6) Chemello et al. (9)
115 10 410 450 440
27 5 62 80 107
HCV RNA negative Normal ALT and RNA negative Normal ALT 12 months Normal ALT and HCV RNA Negative Normal ALT 12 months
3.5-8.8 613 26 l-7.6 0.5-3
5.4 10 3 4 3
Vento et al. (11)
-
Normal ALT and RNA negative 12 months
&7.5
22126 (85% 4/5 (80%) 74/80 (93%) 19127with negative RNA l/29 (3%)
24126 (92%) s/s (100%) 56/62 (90%) 72l75 (96%) O/80 RNA negative O/29
29
6.5
245
E. Barnes et al.
has not been constant enough, however, to provide a starting point to determine LTR. Also, both biochemical and virological response have been used to determine response. When PCR was used to determine virological response, the sensitivity of the technique varied from 100 to 1000 copies/ml. Patients were treated within different protocols, with different doses of alpha interferon, and varying duration of treatment. Patients have been followed for varying lengths of time. Several authors have reported data after following patients to week 72 after 24 weeks of treatment, allowing some assessment of LTR. These have provided some information on LTR (3, 4). More recent studies examined patients who were HCV RNA negative by PCR 6-12 months after stopping alpha interferon monotherapy. Reichard et al. reported long-term follow-up of chronic hepatitis C patients with sustained virological responses to alpha interferon (5). The cohort initially included 115 patients who had been included in three trials of alpha interferon; 27 of these patients were defined as having a sustained virological response, based on HCV RNA negativity in serum at follow-up, 6 months after the end of treatment. These patients had received treatment for 36-60 weeks. Biochemical and virological long-term follow-up had been performed for 3.5-8.8 years (mean 5.4 years) after the end of interferon therapy. Twenty-two of 26 sustained virological responders (85%) had normal serum aminotransferase levels and 24 patients (92%) were HCV RNA negative in serum. Marcellin et al. examined the long-term outcome in 80 patients with a sustained response, who had a mean follow-up of 4.0 years (range l-7.6 years) after treatment (6). In this study, sustained response was defined as normal serum ALT levels every month for the first 6 months after stopping treatment, and negative serum HCV RNA by PCR (Amplicor, Roche Products) 6 months after treatment. During long-term follow-up, 93% of patients had persistently normal serum ALT levels and 96% remained serum HCV RNA negative. Lau et al. evaluated the long-term outcome of 10 patients with chronic hepatitis C who had been treated more than a decade ago with alpha 2b interferon. Among five patients who had a g-month sustained response after treatment, all had remained hepatitis C
RNA negative and four had normal serum ALT levels. These results compared favourably with five patients who did not have a sustained response and who continued to have HCV RNA in serum with elevated serum ALT levels. One patient had progressive hepatic decompensation and another required liver transplantation (7). Camma et al. (8) followed sustained responders from a cohort of 410 consecutive patients who were treated with alpha-interferon within two trials. Mean followup was 62 months. Response was detined as normal serum aminotransferases 12 months after stopping interferon. Fifteen per cent of the treated cohort were sustained responders. No biochemical relapse after 12 months was seen in sustained responders irrespective of the initial histology or genotype (8). Chemello et al. (9) noted that HCV RNA negative patients, followed beyond the first year after treatment, maintained normal serum ALT levels, and remained negative for HCV RNA, whereas a biochemical relapse was noted in 30% of viraemic patients. In this study, the estimated probability of a return to elevated serum ALT levels 4 years after cessation of treatment was 53% in viraemic patients, and 0% in the non viraemic patients (9). Others have reported fluctuating HCV RNA concentrations in responders demonstrated by intermittently positive serum HCV RNA, or even a marked lack of sustained efficacy after alpha interferon treatment of hepatitis C (10, 11). There is less information regarding long-term outcome of alpha interferon treatment in kidney transplantation patients, children, HIV positive carriers, haemophiliacs, thalassaemics or after liver transplantation (12). Histological response
Most studies examining the long-term efficacy of alpha interferon monotherapy have not included a histological assessment. Marcellin et al. examined liver biopsies taken from 48 sustained responders from 1 to 6 years after stopping treatment (6). Liver biopsies showed nearly normal histological findings in 62% of these patients. One to 5 years after treatment, liver HCV RNA was not detectable in any of the 27 patients tested. In the study by Lau et al. (7), liver biopsies 5-11 years
TABLE 2 Long-term response in patients with sustained response after ribavirin and alpha interferon treatment n
Sustained response
Definition of sustained response
Duration of treatment (months)
Follow-up (months)
Mean follow-up (months)
RNA negative and normal ALT
73
25
RNA neg and Normal ALT
1-12 months
1-21
9.6
21/25 (84%)
246
Chronic HCV treatment
after therapy in five sustained responders showed improvements in inflammation and fibrosis with generally mild low-grade non-specific inflammatory changes; HCV RNA was not detected in the liver; liver biopsies showed little change in necrosis or inflammation in non sustained responders. Tsubota et al. (13) retrospectively analysed 105 paired liver biopsy specimens from 93 patients with biochemical remission and negative HCV RNA, for up to 60 months. They found that histological grading scores improved significantly after therapy. Most sustained virological responders showed disappearance of periportal necrosis (84/105), and lobular inflammation (65/105) post follow-up, but inflammatory cell infiltrates remained within the portal tracts for long periods; only 10 of 105 patients had disappearance of portal infiltrates (13). An improvement in the numerical score of fibrosis occurred in 66/ 93 sustained responders. Fibrosis scores showed complete or near normalisation in 5/93 sustained responders. Larghi et al. (14) followed 25 long-term responders for a median of 39 months after discontinuing alpha interferon. A liver biopsy was performed before treatment and 612 months after stopping alpha interferon. Both liver and serum HCV RNA were tested. Twenty two patients tested negative for HCV RNA in both liver and serum, two patients had detectable HCV RNA in both liver and serum and one had detectable HCV RNA only in the liver. Post treatment liver histology was markedly improved, including in those with persistent RNA (14). Liver biopsies before treatment and at the end of treatment were compared. No significant change in fibrosis was found (total morphometric collagen). Duchatelle et al. morphometrically evaluated hepatic fibrosis, including total collagen and Disse space collagen deposits, using an automated image analysis system with Picrosirius staining, up to 18 months after treatment in 70 patients treated with alpha 2b interferon (15). A decrease in Disse space collagen was observed at the end of treatment and 6 months later, which was also observed (although non significant) up to 18 months after treatment. Interestingly, there was no relationship between this decrease and a biochemical or virological response. These data would suggest that alpha interferon may have an anti-fibrogenic effect. Symptomatic response
Symptoms and quality of life may improve after successful treatment of hepatitis C, suggesting that this objective of treatment can be met. For example, health related quality of life indices, particularly anxiety and
depression, during and following alpha interferon therapy have been evaluated. In one study these measures were compared with the results of healthy adults in the general population. Anxiety scores improved significantly after alpha interferon in comparison with pretreatment results. Most important, alpha interferon responders who were aware of their serum aminotransferase results had lower scores on anxiety scales during and after therapy and had fewer emotional problems following therapy (16).
Long-term response data for combination therapy with ribavirin and alpha interferon Biochemicallvirological response
Large placebo controlled trials have recently shown that 40% of patients treated with alpha interferon in combination with ribavirin achieve a virological sustained response (17, 18). It is not yet known if these patients maintain a virological response beyond this time frame. We have examined long-term response, defined as an absence of HCV RNA detectable by RT PCR of the S’non-coding region and normal serum aminotransaminases beyond the period defined as a sustained response. We studied 73 patients (45 male, 28 female) who received combination therapy with alpha interferon and ribavirin between May 1995 and March 1998. Alpha interferon was administered at a dose of 3 MU three times a week with ribavirin at a dose ranging from 300 mg to 1.2 g daily. Patients who achieved a sustained response were then further analysed to assess the long-term response to treatment. Results were unavailable for 12 patients who had moved out of the area or who had failed to attend follow-up appointments. Of the remaining 61 patients, 27 had no response (NR) to combination treatment (defined as elevated transaminases or HCV RNA detectable by RT PCR at the end of treatment). The mean duration of treatment in this group was 5.4 months (range 1-12). However, one patient with NR to 6 weeks of combination treatment later achieved a long-term virological and biochemical response of 29 months. (An end of treatment response (ETR) was observed in five patients who failed to achieve a sustained response and in two patients who were followed up for less than 6 months following treatment). We observed a virological and biochemical sustained response in 25 patients. A long-term virological and biochemical response was observed in 21 of these patients (84%), with a mean long-term follow-up of 9.4 months (range 1-21 months). These patients were treated for a mean of 8.4 months (range 3-12 months). The remaining four patients (16%) achieved a longterm biochemical response only, with a mean follow247
E. Barnes et al.
up of 11 months (range 9-12 months). These four patients were treated for a mean of 7.8 months (range 67 months) but after a mean of 7.5 months, HCV RNA was again detectable by RTPCR. There was no significant difference in the genotypes of patients who achieved a long-term response and patients who failed to maintain a long-term virological response. Thus, a virological and biochemical sustained response was achieved in 25/73 (35%) of patients treated with combination therapy, in support of recently published randomised controlled trials. A long-term virological and biochemical response was achieved in 84% of patients who achieved a sustained response with a mean followup of 9.4 months. Most sustained responders treated with combination ribavirin and alpha interferon will probably continue to have a long-term biochemical and virological response, as has been demonstrated for LTR with interferon alone, but further long-term follow-up of patients treated with combination therapy is required.
Disease progression in long-term responders We are at a point where it should be possible to determine whether the disease outcome can be modified by treatment. It has been noted in several trials that sustained virological responders appear less likely to progress to the complications of liver disease, although the number of patients has been relatively small. Camma et al. (8) reported that the complications of liver disease, including development of ascites, portal hypertension, and hepatocellular carcinoma, occurred in relapsers and non responders, but that event-free survival was significantly longer in sustained responders. Multivariate analysis showed that sustained response to interferon, younger patients and absence of pre-treatment cirrhosis were independent predictors of event-free survival. However, when a subgroup analysis limited to patients with cirrhosis was performed, neither sustained response to interferon nor age was a significant predicator of disease free survival, suggesting the importance of cirrhosis in determining outcome.
Conclusions The bulk of evidence suggests that the majority (90%) of patients with a sustained virological response to alpha interferon monotherapy, assessed with sensitive RTPCR to detect viraemia months after therapy, will remain HCV RNA negative for 5 years after stopping therapy. These patients show a decrease in total inflammatory activity and may show some decrease in the reversible components of fibrosis. It seems reasonable to conclude that in most patients with sustained
248
virological responses there will be a favourable longterm biochemical and histological outcome. It is not yet clear whether these parameters are equivalent to a “cure” of hepatitis C, and this may not reflect definitive viral clearance. Only a few studies have looked for HCV RNA in the liver. Most of these studies did not find detectable liver HCV RNA but one study reported the presence of detectable HCV RNA in the liver in serum HCV RNA negative patients accompanied by ongoing inflammatory change (19). However, if serum HCV RNA mirrors the hepatic burden of hepatitis C virus, and the risk of disease progression is related to the hepatic burden of HCV RNA, then perhaps most sustained virological responders can be considered to be at less risk of disease progression. Recently published studies have shown that a higher frequency of sustained response is seen in patients treated with combination therapy than with alpha interferon monotherapy. A preliminary analysis of patients who received combination therapy suggests that LTR is maintained in most who achieve a sustained virological and biochemical response. Further studies are required, involving larger numbers of patients followed over a longer period, to confirm the initial promise of combination therapy in chronic HCV
Future studies Measurement of HCV RNA in liver tissue may be important to establish viral clearance. Research studies could concentrate on alterations in the immune response after viral clearance, including CTL and proliferative T cell responses and cytokine patterns (2& 24). These studies could determine whether the absence of detectable viraemia is due to an immune response which contains residual HCV infection, or is due to non productively infective cells, or to clearance via infected hepatocyte turnover. Research may also show whether there is an association between HLA class II genotype and long-term clearance of hepatitis C viraemia as has been reported for spontaneous clearance of hepatitis C viraemia (25). The natural history of the disease in these patients requires continued monitoring, but the lasting biochemical and particularly virological responses provide a rationale and an economic argument for treatment of chronic hepatitis C.
References 1. Benvegnh L, Chemello L, Noventa F, Fattovich G, Pontisso P, Alberti A. Retrospective analysis of the effect of interferon therapy on the clinical outcome of patients with viral cirrhosis. Cancer 1998: 83: 901-909. 2. Fattovich G, Giustina G, Degos F, Diodati G, Tremolada F, Nevens F et al. Effectiveness of interferon alpha on incidence of
Chronic HCV treatment hepatocellular carcinoma and decompensation in cirrhosis type C. J Hepatol 1997: 27: 201-205. 3. Manesis EK, Papaioannou C, Gioustozi A, Kafiri G, Koskinas J, Hadziyannis SJ. Biochemical and virological outcome of patients with chronic hepatitis C treated with interferon alpha-2b for 6 or 12 months: A 4-year follow-up of 211 patients. Hepatology 1997: 26: 734-739. 4. Saracco G, Rosina F, Abate ML, Chiandussi L, Gallo V, Cerutti E et al. Long-term follow-up of patients with chronic hepatitis C treated with different doses of interferon-azb. Hepatology 1993: 18: 130&1305. 5. Reichard 0, Glaumann H, Fryden A, Norkrans G, Wejstal R, Weiland 0. Long-term follow up of chronic hepatitis C patients with sustained virological response to alpha interferon. J Hepatol 1999: in press. 6. Marc&n E Boyer N, Gervais A, Martinot M, Pouteau M, Castelnau C et al. Long-term histologic improvement and loss of detectable intrahepatic HCV RNA in patients with chronic hepatitis C and sustained response to interferon-a therapy. Ann Intern Med 1997: 127: 875-881. 7. Lau DT, Kleiner DE, Ghany MG, Park Y, S&mid P, Hoofnagle JH. lo-year follow-up after interferon-a therapy for chronic hepatitis C. Hepatology 1998: 28: 1121-1127. 8. Camma C, Di Marco V, Lo I, Ahnasio E Giunta M, Fuschi P et al. Long-term course of interferon-treated chronic hepatitis C. J Hepatol 1998: 28: 531-537. 9. Chemello L, Cavalletto L, Casarin C, Bonetti E Bernardinello E, Pontisso P et al. Persistent hepatitis C viremia predicts late relapse after sustained response to interferon-a in chronic hepatitis C. Ann Intern Med 1996: 124: 1058-1060. 10. Castillo I, Bartolome J, Navas S, Gonzalez S, Herrero M, Carrefio V Virological and biochemical long-term follow-up of patients with chronic hepatitis C treated with interferon. Hepatology 1994: 19: 1342-1346. 11. Vento S, Concia E, Ferraro T. Lack of sustained efficacy of interferon in patients with chronic hepatitis C. N Engl J Med 1996: 334: 1479-1480. 12. Biden K, Young J, Buttenshaw R, Searle J, Cooksley G, Xu DB, Leggett B. Frequency of mutation and deletion of the tumor suppressor gene CDKN2A (MTSllpl6) in hepatocellular carcinoma from an Australian population. Hepatology 1997: 25: 593-597. 13. Tsubota A, Kumada H, Chayama K, Arase Y, Saitoh S, Koida I et al. Time course of histological changes in patients with a sustained biochemical and virological response to interferon-a therapy for chronic hepatitis C virus infection. J Hepatol 1997: 21: 49-55.
14. Larghi A, Tagger A, Crosignani A, Ribero ML, Bruno S, Portera G et al. Clinical signiIicance of hepatic HCV RNA in patients with chronic hepatitis C demonstrating long-term sustained response to interferon-alpha therapy. J Med Virol 1998: 55: 715. Duchatelle V, Marcellin P, Giostra E, Bregeaud L, Pouteau M, Boyer N et al. Changes in liver fibrosis at the end of alpha interferon therapy and 6 to 18 months later in patients with chronic hepatitis C: quantitative assessment by a morphometric method. J Hepatol 1998: 29: 2&28. 16. Hunt CM, Dominitz JA, Bute BE Waters B, Blasi U, Williams DM. Effect of interferon-a treatment of chronic hepatitis C on health-related quality of life. Dig Dis Sci 1997: 42: 2482-2486. 17. McHutchison JG, Gordon SC, Schiff ER, Shiffman ML, Lee WM, Rustgi VK et al. Interferon alpha-2b alone or in combination with ribavirin as initial treatment for chronic hepatitis C. N Engl J Med 1998: 339: 1485-1492. 18. Davidson F, Simmonds E Ferguson JC, Jarvis LM, Dow BC, Follett EAC et al. Survey of major genotypes and subtypes of hepatitis C virus using RFLP of sequences amplified from the 5’ non-coding region. J Gen Virol 1995: 76: 1197-1204. 19. Dries V, Von Both I, Muller M, Gerken G, Schirmacher E Odenthal M et al. Detection of hepatitis C virus in paraffin-embedded liver biopsies of patients negative for viral RNA in serum. Hepatology 1999: 29: 22>229. 20. Chang KM, Rehermam B, Chisari FV Immunopathology of hepatitis C. Springer Sem Immunopathol 1997: 19: 57-68. 21. Spengler U, Lechmann M, Irrgang B, Dumoulin FL, Sauerbruch T. Immune responses in hepatitis C virus infection. J Hepatol 1996: 24: 20-25. 22. Bertoletti A, D’Elios MM, Boni C, De Carli M, Zignego AL, Durazzo M et al. Different cytokine profiles of intrahepatic T cells in chronic hepatitis B and hepatitis C virus infections. Gastroenterology 1997: 112: 193-199. 23. Cacciarelli TV Martinez OM, Gish RG, Villanueva JC, Krams SM. Immunoregulatory cytokines in chronic hepatitis C virus infection: Pre- and posttreatment with interferon alpha. Hepatology 1996: 24: 6-9. 24. Fabris C, Soardo G, Falleti E, Toniutto P Vitulli D, Federico E et al. Relationship among hepatic inflammatory changes, circulating levels of cytokines, and response to IFN-a in chronic hepatitis C. J Interferon Cytokine Res 1998: 18: 705-709. 25. Cramp ME, Carucci E Underhill J, Naoumov NV, Williams R, Donaldson PT. Association between HLA class II genotype and spontaneous clearance of hepatitis C viraemia. J Hepatol 1998: 29 (2): 207-213.
249
Copyright 0 European Association for the Study of the Liver 1999 Journal of Hepatology
ISSN 01694185 ISBN 87-16-16386-9
Long-term efficacy of treatment of chronic hepatitis C with alpha interferon or alpha interferon and ribavirin Eleanor
Barnes, George Webster, Ruth Jacobs and Geoffrey
Dusheiko
Department of Medicine, Royal Free and University College School of Medicine, London, United Kingdom
The major objective of treatment of chronic hepatitis C virus (HCV) infection is to prevent progression to cirrhosis, and thereby prevent complications of end-stage liver disease. The established treatment of chronic HCV is with alpha interferon. Recent results with ribavirin and alpha interferon together suggest that combination antiviral therapy will become the benchmark treatment. For both naive and relapsed patients, however, it has become important to assess the long-term outcome of treatment, in order to gauge whether treatment has indeed modified the natural history of chronic
hepatitis C virus infection. It seems likely that most sustained responders (85-W”/) treated with combination ribavirin and alpha interferon will continue to have a long-term biochemical and virological response, as has been demonstrated with alpha interferon alone, but further long-term follow-up of patients treated with combination therapy is required.
MAJORobjective of treatment of chronic hepatitis C virus (HCV) infection is to prevent progression to cirrhosis, and thereby prevent the complications of end-stage liver disease. The established treatment of chronic HCV is with alpha interferon. Recent results with ribavirin and alpha interferon together suggest that combination antiviral therapy will become the benchmark treatment. Earlier trials with alpha interferon monotherapy for both 6 and 12 months of treatment indicated the tendency of patients to relapse after an initial biochemical response to alpha interferon therapy. Combination therapy with alpha interferon and ribavirin therapy has proven superior to retreatment with alpha interferon monotherapy in patients who have relapsed after alpha interferon monotherapy, and to treatment with alpha interferon in naive patients. For both naive and relapsed patients, however, it has become important to assess the long-term outcome of treatment, in order to gauge whether treatment has indeed modified the natural history of chronic hepatitis C virus infection. This data has not
been easy to obtain, and surrogate markers are being used to assess disease outcome.
T”
Correspondence: Professor G. Dusheiko, Dept of Medicine, Royal Free and University College School of Medicine, Pond Street, Hampstead, London NW3 2QG, UK. Tel: + 44 171 830 2993. Fax: + 44 171 431 4581. e-mail: [email protected]
244
Key words: Alpha interferon; Antiviral response; Antiviral therapy; Chronic hepatitis C: Ribavirin.
Definition of long-term response Long-term response must be defined. The term is a relative one and the duration of follow-up to clearly define a “long-term” response has not been established. By convention, the primary outcome measure in several controlled trials has been the normalisation of serum ALT and AST 6 months after stopping treatment, defined as a sustained biochemical response. A second outcome measure has been negative serum HCV RNA, measured by PCR, 6 months after stopping treatment (defined as a sustained virological response). Histological assessment has been included as a primary or secondary outcome measure in several studies. Assessment of LTR requires a precise definition of the end-of-treatment response, and sustained response, as the long-term durability of a sustained virological response probably depends upon the absence of detectable HCV RNA 6 months after stopping treatment. Thus the sensitivity of HCV RNA measurement in serum by PCR could affect results, in the same way that the sensitivity and specificity of HCV RNA tests would affect the predictive value of a negative HCV RNA at the end of treatment and follow-up. Unfortunately, HCV RNA measurement remains poorly
Chronic HCV treatment
End of treatment Sustained Long term
ALT
HCV RNA
I-
6-12 Months
-I
6
Histological
Fig. 1. Dejinitions of response.
standardised. Likewise, quantitation and interpretation of histological response will also require further technical development, in order to interpret the consequences of apparently favourable antiviral therapy. Assessment of histological response will depend upon the development of acceptable scoring systems to measure necroinflammatory parameters and fibrosis. The sensitivity and agreement of measures of hepatocellular damage have not been confirmed. The definitions of tissue inflammation and necrosis are not stringent, and are subject to observer and sampling error. Also, patients are often not biopsied years after stopping therapy, and only a few studies have addressed the important question of long-term histological improvement. Other parameters might be able to be used to assess long-term response and disease modification. These could include measurement of HCV RNA in liver tissue, HCV antigens in liver tissue, serum markers of fibrosis, possibly seroreversion to negative anti-HCV,
or a decrease in titres and even disappearance of antiE2 antibodies. An assessment of symptoms and improvement in the quality of life is feasible after an apparent antiviral response. Studies to determine whether there is a reduced progression of liver disease to decompensation, hepatocellular failure, liver transplantation or the development of hepatocellular carcinoma will be important, particularly in patients with established or advanced fibrosis prior to antiviral treatment (1, 2).
Long-term response data for alpha interferon monotherapy Biochemicallvirological response
There is relatively little data concerning LTR in patients with a sustained response to alpha interferon monotherapy. In general, these studies have followed patients for varying lengths of time but in some cases for several years. The definition of sustained response
TABLE 1 Long-term response (LTR) in patients with sustained response (SR) to alpha interferon monotherapy Author
n
Sustained response
Definition sustained response
Follow-up (years)
Mean follow-up
Normal ALT
Negative HCV RNA
Reichard 1999 Lau et al. (7) Camma et al. (8) Marcellin et al. (6) Chemello et al. (9)
115 10 410 450 440
27 5 62 80 107
HCV RNA negative Normal ALT and RNA negative Normal ALT 12 months Normal ALT and HCV RNA Negative Normal ALT 12 months
3.5-8.8 613 26 l-7.6 0.5-3
5.4 10 3 4 3
Vento et al. (11)
-
Normal ALT and RNA negative 12 months
&7.5
22126 (85% 4/5 (80%) 74/80 (93%) 19127with negative RNA l/29 (3%)
24126 (92%) s/s (100%) 56/62 (90%) 72l75 (96%) O/80 RNA negative O/29
29
6.5
245
E. Barnes et al.
has not been constant enough, however, to provide a starting point to determine LTR. Also, both biochemical and virological response have been used to determine response. When PCR was used to determine virological response, the sensitivity of the technique varied from 100 to 1000 copies/ml. Patients were treated within different protocols, with different doses of alpha interferon, and varying duration of treatment. Patients have been followed for varying lengths of time. Several authors have reported data after following patients to week 72 after 24 weeks of treatment, allowing some assessment of LTR. These have provided some information on LTR (3, 4). More recent studies examined patients who were HCV RNA negative by PCR 6-12 months after stopping alpha interferon monotherapy. Reichard et al. reported long-term follow-up of chronic hepatitis C patients with sustained virological responses to alpha interferon (5). The cohort initially included 115 patients who had been included in three trials of alpha interferon; 27 of these patients were defined as having a sustained virological response, based on HCV RNA negativity in serum at follow-up, 6 months after the end of treatment. These patients had received treatment for 36-60 weeks. Biochemical and virological long-term follow-up had been performed for 3.5-8.8 years (mean 5.4 years) after the end of interferon therapy. Twenty-two of 26 sustained virological responders (85%) had normal serum aminotransferase levels and 24 patients (92%) were HCV RNA negative in serum. Marcellin et al. examined the long-term outcome in 80 patients with a sustained response, who had a mean follow-up of 4.0 years (range l-7.6 years) after treatment (6). In this study, sustained response was defined as normal serum ALT levels every month for the first 6 months after stopping treatment, and negative serum HCV RNA by PCR (Amplicor, Roche Products) 6 months after treatment. During long-term follow-up, 93% of patients had persistently normal serum ALT levels and 96% remained serum HCV RNA negative. Lau et al. evaluated the long-term outcome of 10 patients with chronic hepatitis C who had been treated more than a decade ago with alpha 2b interferon. Among five patients who had a g-month sustained response after treatment, all had remained hepatitis C
RNA negative and four had normal serum ALT levels. These results compared favourably with five patients who did not have a sustained response and who continued to have HCV RNA in serum with elevated serum ALT levels. One patient had progressive hepatic decompensation and another required liver transplantation (7). Camma et al. (8) followed sustained responders from a cohort of 410 consecutive patients who were treated with alpha-interferon within two trials. Mean followup was 62 months. Response was detined as normal serum aminotransferases 12 months after stopping interferon. Fifteen per cent of the treated cohort were sustained responders. No biochemical relapse after 12 months was seen in sustained responders irrespective of the initial histology or genotype (8). Chemello et al. (9) noted that HCV RNA negative patients, followed beyond the first year after treatment, maintained normal serum ALT levels, and remained negative for HCV RNA, whereas a biochemical relapse was noted in 30% of viraemic patients. In this study, the estimated probability of a return to elevated serum ALT levels 4 years after cessation of treatment was 53% in viraemic patients, and 0% in the non viraemic patients (9). Others have reported fluctuating HCV RNA concentrations in responders demonstrated by intermittently positive serum HCV RNA, or even a marked lack of sustained efficacy after alpha interferon treatment of hepatitis C (10, 11). There is less information regarding long-term outcome of alpha interferon treatment in kidney transplantation patients, children, HIV positive carriers, haemophiliacs, thalassaemics or after liver transplantation (12). Histological response
Most studies examining the long-term efficacy of alpha interferon monotherapy have not included a histological assessment. Marcellin et al. examined liver biopsies taken from 48 sustained responders from 1 to 6 years after stopping treatment (6). Liver biopsies showed nearly normal histological findings in 62% of these patients. One to 5 years after treatment, liver HCV RNA was not detectable in any of the 27 patients tested. In the study by Lau et al. (7), liver biopsies 5-11 years
TABLE 2 Long-term response in patients with sustained response after ribavirin and alpha interferon treatment n
Sustained response
Definition of sustained response
Duration of treatment (months)
Follow-up (months)
Mean follow-up (months)
RNA negative and normal ALT
73
25
RNA neg and Normal ALT
1-12 months
1-21
9.6
21/25 (84%)
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Chronic HCV treatment
after therapy in five sustained responders showed improvements in inflammation and fibrosis with generally mild low-grade non-specific inflammatory changes; HCV RNA was not detected in the liver; liver biopsies showed little change in necrosis or inflammation in non sustained responders. Tsubota et al. (13) retrospectively analysed 105 paired liver biopsy specimens from 93 patients with biochemical remission and negative HCV RNA, for up to 60 months. They found that histological grading scores improved significantly after therapy. Most sustained virological responders showed disappearance of periportal necrosis (84/105), and lobular inflammation (65/105) post follow-up, but inflammatory cell infiltrates remained within the portal tracts for long periods; only 10 of 105 patients had disappearance of portal infiltrates (13). An improvement in the numerical score of fibrosis occurred in 66/ 93 sustained responders. Fibrosis scores showed complete or near normalisation in 5/93 sustained responders. Larghi et al. (14) followed 25 long-term responders for a median of 39 months after discontinuing alpha interferon. A liver biopsy was performed before treatment and 612 months after stopping alpha interferon. Both liver and serum HCV RNA were tested. Twenty two patients tested negative for HCV RNA in both liver and serum, two patients had detectable HCV RNA in both liver and serum and one had detectable HCV RNA only in the liver. Post treatment liver histology was markedly improved, including in those with persistent RNA (14). Liver biopsies before treatment and at the end of treatment were compared. No significant change in fibrosis was found (total morphometric collagen). Duchatelle et al. morphometrically evaluated hepatic fibrosis, including total collagen and Disse space collagen deposits, using an automated image analysis system with Picrosirius staining, up to 18 months after treatment in 70 patients treated with alpha 2b interferon (15). A decrease in Disse space collagen was observed at the end of treatment and 6 months later, which was also observed (although non significant) up to 18 months after treatment. Interestingly, there was no relationship between this decrease and a biochemical or virological response. These data would suggest that alpha interferon may have an anti-fibrogenic effect. Symptomatic response
Symptoms and quality of life may improve after successful treatment of hepatitis C, suggesting that this objective of treatment can be met. For example, health related quality of life indices, particularly anxiety and
depression, during and following alpha interferon therapy have been evaluated. In one study these measures were compared with the results of healthy adults in the general population. Anxiety scores improved significantly after alpha interferon in comparison with pretreatment results. Most important, alpha interferon responders who were aware of their serum aminotransferase results had lower scores on anxiety scales during and after therapy and had fewer emotional problems following therapy (16).
Long-term response data for combination therapy with ribavirin and alpha interferon Biochemicallvirological response
Large placebo controlled trials have recently shown that 40% of patients treated with alpha interferon in combination with ribavirin achieve a virological sustained response (17, 18). It is not yet known if these patients maintain a virological response beyond this time frame. We have examined long-term response, defined as an absence of HCV RNA detectable by RT PCR of the S’non-coding region and normal serum aminotransaminases beyond the period defined as a sustained response. We studied 73 patients (45 male, 28 female) who received combination therapy with alpha interferon and ribavirin between May 1995 and March 1998. Alpha interferon was administered at a dose of 3 MU three times a week with ribavirin at a dose ranging from 300 mg to 1.2 g daily. Patients who achieved a sustained response were then further analysed to assess the long-term response to treatment. Results were unavailable for 12 patients who had moved out of the area or who had failed to attend follow-up appointments. Of the remaining 61 patients, 27 had no response (NR) to combination treatment (defined as elevated transaminases or HCV RNA detectable by RT PCR at the end of treatment). The mean duration of treatment in this group was 5.4 months (range 1-12). However, one patient with NR to 6 weeks of combination treatment later achieved a long-term virological and biochemical response of 29 months. (An end of treatment response (ETR) was observed in five patients who failed to achieve a sustained response and in two patients who were followed up for less than 6 months following treatment). We observed a virological and biochemical sustained response in 25 patients. A long-term virological and biochemical response was observed in 21 of these patients (84%), with a mean long-term follow-up of 9.4 months (range 1-21 months). These patients were treated for a mean of 8.4 months (range 3-12 months). The remaining four patients (16%) achieved a longterm biochemical response only, with a mean follow247
E. Barnes et al.
up of 11 months (range 9-12 months). These four patients were treated for a mean of 7.8 months (range 67 months) but after a mean of 7.5 months, HCV RNA was again detectable by RTPCR. There was no significant difference in the genotypes of patients who achieved a long-term response and patients who failed to maintain a long-term virological response. Thus, a virological and biochemical sustained response was achieved in 25/73 (35%) of patients treated with combination therapy, in support of recently published randomised controlled trials. A long-term virological and biochemical response was achieved in 84% of patients who achieved a sustained response with a mean followup of 9.4 months. Most sustained responders treated with combination ribavirin and alpha interferon will probably continue to have a long-term biochemical and virological response, as has been demonstrated for LTR with interferon alone, but further long-term follow-up of patients treated with combination therapy is required.
Disease progression in long-term responders We are at a point where it should be possible to determine whether the disease outcome can be modified by treatment. It has been noted in several trials that sustained virological responders appear less likely to progress to the complications of liver disease, although the number of patients has been relatively small. Camma et al. (8) reported that the complications of liver disease, including development of ascites, portal hypertension, and hepatocellular carcinoma, occurred in relapsers and non responders, but that event-free survival was significantly longer in sustained responders. Multivariate analysis showed that sustained response to interferon, younger patients and absence of pre-treatment cirrhosis were independent predictors of event-free survival. However, when a subgroup analysis limited to patients with cirrhosis was performed, neither sustained response to interferon nor age was a significant predicator of disease free survival, suggesting the importance of cirrhosis in determining outcome.
Conclusions The bulk of evidence suggests that the majority (90%) of patients with a sustained virological response to alpha interferon monotherapy, assessed with sensitive RTPCR to detect viraemia months after therapy, will remain HCV RNA negative for 5 years after stopping therapy. These patients show a decrease in total inflammatory activity and may show some decrease in the reversible components of fibrosis. It seems reasonable to conclude that in most patients with sustained
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virological responses there will be a favourable longterm biochemical and histological outcome. It is not yet clear whether these parameters are equivalent to a “cure” of hepatitis C, and this may not reflect definitive viral clearance. Only a few studies have looked for HCV RNA in the liver. Most of these studies did not find detectable liver HCV RNA but one study reported the presence of detectable HCV RNA in the liver in serum HCV RNA negative patients accompanied by ongoing inflammatory change (19). However, if serum HCV RNA mirrors the hepatic burden of hepatitis C virus, and the risk of disease progression is related to the hepatic burden of HCV RNA, then perhaps most sustained virological responders can be considered to be at less risk of disease progression. Recently published studies have shown that a higher frequency of sustained response is seen in patients treated with combination therapy than with alpha interferon monotherapy. A preliminary analysis of patients who received combination therapy suggests that LTR is maintained in most who achieve a sustained virological and biochemical response. Further studies are required, involving larger numbers of patients followed over a longer period, to confirm the initial promise of combination therapy in chronic HCV
Future studies Measurement of HCV RNA in liver tissue may be important to establish viral clearance. Research studies could concentrate on alterations in the immune response after viral clearance, including CTL and proliferative T cell responses and cytokine patterns (2& 24). These studies could determine whether the absence of detectable viraemia is due to an immune response which contains residual HCV infection, or is due to non productively infective cells, or to clearance via infected hepatocyte turnover. Research may also show whether there is an association between HLA class II genotype and long-term clearance of hepatitis C viraemia as has been reported for spontaneous clearance of hepatitis C viraemia (25). The natural history of the disease in these patients requires continued monitoring, but the lasting biochemical and particularly virological responses provide a rationale and an economic argument for treatment of chronic hepatitis C.
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