Benefit of Sustained Virological Response to Combination Therapy on Graft Survival of Liver Transplanted Patients with Recurrent Chronic Hepatitis C

Authors


*Corresponding author: Thierry Bizollon, thierry.bizollon@chu-lyon.fr

Abstract

Recurrent hepatitis C infection is an important cause of progressive fibrosis, cirrhosis and graft loss after liver transplantation. Treatment for post-transplant recurrence results in sustained virological response (SVR) in up to 30% of cases. The aim of this study was to evaluate the impact of SVR on patients and graft survival. Thirty-four patients with an SVR to IFN-ribavirin were included. Forty-six nonresponders to the combination formed the control group. Follow-up data were recorded every 6 months and included HCV RNA, and the occurrence of clinical problems (cirrhosis, decompensation, hepatocellular carcinoma, death). A graft biopsy was performed every year. The mean follow-up duration was 52 months in responders and 57 months in nonresponders. Two patients died in each group of patients. Two patients with SVR developed late virological relapse. Fibrosis decreased in 38% of patients with SVR, remained stable in 44% and worsened in 18%. In contrast, fibrosis increased in the majority of nonresponder patients (74%, p < 0.001). At the end of follow-up, no patient without cirrhosis at inclusion developed cirrhosis of the graft versus 9 among nonresponder patients (p = 0.009). No difference in patient survival was observed in the two groups. In conclusion, this study shows that HCV eradication has a positive impact on graft survival.

Introduction

Despite the improved efficacy of antiviral therapy, hepatitis C virus (HCV) infection remains the predominant cause of cirrhosis and hepatocellular carcinoma (HCC) in the United States and Western Europe (1,2). Liver disease due to hepatitis C has become one of the leading indication for liver transplantation. Unfortunately, almost all recipients of transplants for HCV disease develop recurrent infection of the liver allograft (3). The risk of progression from chronic hepatitis to cirrhosis is accelerated in comparison to immunocompetent patients: at 5 years post-orthotopic liver transplantation (OLT), more than 20% of patients have severe graft damage (4,5). Recently, it has been shown that HCV-related graft disease is more severe in the most recently transplanted patients (6). Donor age seems to be the major determinant of the rate of fibrosis progression (7,8). Due to a growing demand for liver transplants and an increasingly acute shortage of cadaveric donor organs, the need to optimize outcomes following liver transplantation is one of the most pressing issues facing the transplant community. Our recent studies have shown that interferon/ribavirin combination therapy may achieve a 20% sustained virological response (SVR) (9,10) and is superior to the absence of treatment. However, little information is available on histological outcome and the question of the long-term benefits of combination therapy with regard to HCV clearance and histological improvement remains to be answered. In a previous study we reported durable eradication of HCV infection in 13 patients after a 3-year follow-up (11). However, in this small study the question of the benefit of SVR on the natural history of HCV infection after OLT was not completely resolved. Furthermore, the absence of control group in this study was a serious limitation in interpreting the clinical implications of our results. A study of HCV-infected liver transplant recipients treated with combination therapy comparing those with SVR and nonresponders was necessary to assess whether SVR had an impact on patients and grafts survival.

Patients and Methods

Between October 1990 and May 2001, 142 patients underwent OLT for HCV cirrhosis at our institution. Since 1994, patients have been treated with IFN-ribavirin combination therapy for 48 weeks if they fulfilled the following criteria: (1) survival over 6 months after OLT; (2) detection of HCV RNA in serum and (3) presence of chronic hepatitis on graft biopsy. All patients were treated with nonpegylated IFN. Antiviral therapy was usually started within 6 months after diagnosis of HCV recurrence. Patients with normal ALT could be included. Patients should be on cyclosporin or tacrolimus at the time of inclusion, but some patients did not receive the same immunosuppressive medication during the antiviral therapy. Immunosuppression was not adjusted in liver recipients with histologically documented recurrent chronic hepatitis C after OLT. Among the 80 patients with recurrent chronic hepatitis who were treated with combination therapy in our center between 1994 and 1998 (before the availability of pegylated IFN), some patients with therapy failure due to ribavirin withdrawal (16%) were retreated using erythropoietin and achieved SVR after the second course of therapy.

SVR was achieved in 34 patients (42%). SVR was defined as no detectable HCV-RNA at the end of treatment and after 6 months of follow-up. Forty-six patients (58%) failed to respond to combination therapy. Nonresponse was defined as the persistence of HCV-RNA at the end of IFN-ribavirin combination therapy.

Data recorded

Follow-up data were recorded every 6 months and included measurement of serum aminotransferases, hematological monitoring parameters, immunosuppression levels at least every 3 months, HCV-RNA and the occurrence of clinical events (decompensation, HCC, death). Sustained virological responders were considered to have a late virological relapse if HCV RNA was detectable on any occasion, after 6 months of follow-up. Patients were considered to have decompensation if they showed any of the following symptoms: ascites, bleeding varices, jaundice or hepatic encephalopathy. Patients were classified as having developed cirrhosis on the basis of ultrasound (nodular contour, diminished hepatopetal flow, collaterals), serology (platelets <80 000, albumin <35g/L, clotting factors <50%) or liver biopsy. Patients were considered to have HCC if the α-fetoprotein was >400 μg and if ultrasound confirmed a focal lesion, or if biopsy proved so. Death was classified as liver related or liver unrelated.

Qualitative HCV RNA was determined by a polymerase chain reaction based assay (Amplicor HCV version 2.0). HCV RNA was detected in serum at baseline, and then every 6 months. This assay had a detection threshold of 100 copies/mL. Serum HCV RNA level was measured using the b-DNA signal amplification assay with a low-end detection limit of 100 000 genome equivalent/mL (Quantiplex HCV RNA, version 2.0; Chiron Corporation, Emeryville, CA).

Liver biopsy specimens were obtained at inclusion, every year and at the end of follow-up. Slides were stained with hematoxylin-eosin and trichrome. Biopsy specimens were read by the study pathologist in a blinded fashion regarding treatment virological response, and inflammatory activity and fibrosis were scored according to the METAVIR scoring system (12). Graft biopsy specimens were also examined for features of acute and chronic rejection.

End point

The primary objective was to determine the impact of SVR on patients and graft survival. The secondary objective was to confirm the durability of SVR over time.

Statistitical analysis

Categorical variables were analyzed by the X2 test or the Fisher's exact test when appropriate. Continuous numeric variables were analyzed by the Wilcoxon signed-rank test for related samples and the Mann-Whitney U test for independent samples. p values less than 0.05 were considered to be significant. The occurrence of liver cirrhosis was assessed using Kaplan-Meier analysis and the comparison according to treatment status was performed using the log-rank test.

Results

Patients'characteristics

Patients'characteristics are summarized in Table 1. There was no significant difference between the two groups relating to gender, genotype, immunosuppression type, severity of disease and time of inclusion, whereas a difference appeared for age, time between OLT and HCV recurrence, and duration of follow-up.

Table 1.  Patients'characteristics at inclusion
 Nonresponders
(n = 46)
Responders
(n = 34)

p
Mean age (range)54 (42–63)56 (44–68)0.03
Gender (M/F)35/1121/130.16
Genotype 1 (%)40 (87)30 (88)0.86
Immunosuppressive
 drugs
 Cyclosporin740.75
 Prograf3930 
Time between OLT and HCV recurrence (months)22 (18–34)27 (14–31)<0.001
Mean METAVIR scoreA1.8 F2.1A1.9 F2.2-
Period of inclusion (year)1997–20001996–2000-
Mean duration of follow-up (months)57 (32–72)52 (32–72)0.008

Clinical outcome

At the end of follow-up, 33 patients with SVR were alive. One patient died of myocardial infarction 23 months post-inclusion. In this patient group, one patient developed hepatic cholestasis, possibly due to chronic rejection, despite remaining persistently negative for HCV RNA. One nonresponder patient waiting retransplantation died 8 months after cirrhosis decompensation.

The only sustained virological responder with cirrhosis at inclusion did not develop decompensation of cirrhosis or HCC. Nine nonresponder patients developed cirrhosis on the graft (p = 0.009, Figure 1). Among these patients, four with cirrhosis developed decompensation after a mean period of 14 months (range: 6–18 months). None of them developed HCC but three were retransplanted due to liver failure.

Figure 1.

Occurrence of liver cirrhosis in relation to response to therapy. The occurrence of liver cirrhosis was assessed using Kaplan-Meier analysis and the comparison according to treatment status was performed using the log-rank test.

Virological response

During the long-term follow-up period, serum HCV-RNA was persistently undetectable in 32 of 34 (94%) patients with SVR. Two patients developed virological relapse at 8 and 15 months. For the second relapser, the reappearance of HCV RNA occurred 3 months after two treatments with steroid bolus therapy for severe rejection. In this case, the rejection occurred about 6 months after a decrease in immunosuppressive treatment justified by renal disease. In contrast, HCV RNA remained detectable at the end of follow-up in all patients in the nonresponder group. HCV RNA level was not different between the inclusion and the end of follow-up in nonresponders (4.9 Meq/mL vs. 5.4 Meq/mL, p = 0.2).

Histological response

We observed a decrease in necrotico-inflammatory activity in 62% of patients with SVR at the end of follow-up versus 15% in nonresponder patients (Table 2). This improvement is present in 16% of patients after 1 year of follow-up, 28% at 2 years, 36% at 3 years and 62% at the end of follow-up. Fibrosis decreased in 38% of patients with SVR, remained stable in 44% and worsened in 18%. In contrast, fibrosis increased in the majority of nonresponder patients (74%, p < 0.001). None of the patients with SVR developed cirrhosis on the graft during the study. Among nonresponder patients, cirrhosis occurred in nine (20%).

Table 2.  Change in activity score and fibrosis score at the end of follow-up (METAVIR score)
 Nonresponders
(n = 46)
Responders
(n = 34)

p
Necrotico-inflammatory <0.001
 activity 
 Improvement7 (15%)21 (62%) 
 No change15 (33%)10 (29%) 
 Worsening24 (52%)3 (9%) 
Fibrosis <0.001
 Improvement013 (38%) 
 No change12 (26%)15 (44%) 
 Worsening34 (74%)6 (18%) 

Despite the absence of viremia, six recipients had increased fibrosis 2 years after SVR. Among them, three patients suffered chronic rejection without severe ductopenia. Two patients developed late hepatic artery thromboses documented by Doppler ultrasound and angiogram examination of the allograft. In one patient, fibrosis progression may have been due to other mechanisms, such as a drug induced problem or atypical rejection.

Discussion

Although the recurrence of HCV in allografts is universal, preliminary results with a short-term follow-up study in HCV-infected patients suggested that patient and graft survival were similar to those with other indications for OLT. Recently enthusiasm for transplantation in this indication has been tempered by reports of increasing rates of cirrhosis and graft survival loss from recurrent hepatitis beyond the first 5 years after OLT (13–15). It has been suggested that progression to advanced disease occurs at a faster rate in patients who have recently been transplanted (after 1996). Although the reasons are not clear, this may be in part related to more aggressive immunosuppressive regimens and the use of older donors. It is now established that the use of IFN and ribavirin combination therapy is associated with a 10%–30% SVR rate. However the durability of SVR in the setting of chronic immunosuppression and the impact on long-term graft and patient survival has not yet been evaluated.

In a previous study (11) we showed that durable HCV eradication was possible after antiviral therapy, and observed only one relapser among 13 patients with SVR after 3 years of follow-up. In this study, we underlined that the histological benefit, present at the end of treatment, did not increase during follow up. However the absence of a control group was a serious limitation to our conclusions. A study with a longer follow-up was thus necessary to establish whether SVR had an impact on histological evolution and graft survival.

Although it was a retrospective study including a small number of patients, some interesting data should be underlined.

First of all, the present study confirms that durable eradication of HCV is possible in the transplant setting. Indeed, thirty-two patients out of 34 (94%) had an SVR at the end of follow-up. In our previous study, we reported that the late virological relapser was the only patient positive for HCV RNA in the graft at inclusion. A separate manuscript detailing our center's experience about using tissue HCV RNA RT-PCR as a more accurate predictor of SVR is currently in preparation. In fact, many questions, such as the optimal duration of therapy have still not been resolved in the treatment of recurrent HCV infection and it is interesting to speculate that the direct detection of HCV RNA may suggest longer durations, resulting in improved SVR (16,17), especially in patients with genotype 1.

Of the two relapsers, one developed virological relapse 3 months after steroid bolus therapy for severe rejection. In this case, rejection was largely favored by a significant decrease in immunosuppressive therapy justified by impaired renal function. This case does suggest maintaining a stable immunosuppressive therapy in patients with SVR.

The rate of HCV eradication observed in this study is similar to that reported in immunocompetent patients. Marcellin et al. reported a 96% SVR rate (18) and other authors found similar results (19,20). In the transplant setting, only one study by Abdelmalek et al. reported no late relapse after a mean follow-up of 24 months after discontinuing therapy (21).

Most nonresponders were retreated during this period of follow-up with a mean treatment duration of 39 months (range: 18–49). Despite prior treatment in many patients, we observed a progression of fibrosis in most patients. We already made this observation in a previous study (22). These data suggest that the loss of HCV RNA is needed for treatment to confer any beneficial effect in patients with recurrent HCV. Experience in the immunocompetent patient population has been reported to be different (23,24). In such patients, fibrosis generally tends to improve despite the persistence of HCV RNA. Also, large multicenter studies are necessary to confirm the role of long-term IFN therapy in improving liver histology despite the absence of SVR.

In this study we observed a decreased of activity score in 62% of SVR patients. In patients with SVR, analysis of biopsies showed that the improvement was observed in most patients after the second year of follow-up. Two explanations can be put forward for this result. First, the constant presence of inflammatory infiltrates may be due to the persistence of some degree of graft immune response to HCV, which probably takes many years to disappear. Second, the technique may not be sufficiently sensitive to detect low levels of HCV RNA replication and the explanation that there is a continuing low level of HCV RNA replication cannot be entirely excluded. An ideal assessment of this phenomenon would be to assay the liver graft tissue for HCV RNA and follow the host and immune cytokine mediated response over time in those patients who respond to treatment.

Among responder patients without cirrhosis at inclusion, none developed cirrhosis at the end of the follow-up. In nonresponders, 9 of 48 (19%) developed cirrhosis on the graft after a mean period of 32 months (range: 12–45). Four out of nine patients had decompensated cirrhosis. Three patients underwent retransplantation after a mean period of 7 months following diagnosis of cirrhosis. Also, we show in this study that SVR protects from the occurrence of graft loss due to recurrent hepatitis C infection.

One patient had cirrhosis on the graft at inclusion. In this patient, no decompensation or HCC occurred. The last two biopsies in this patient showed the absence of activity. Although only one patient had cirrhosis at inclusion, this case confirms that a clearance of HCV is possible even if cirrhosis is present on the graft.

In conclusion, this study confirms that eradication of HCV can be achieved after transplant in the chronic immunosuppression setting. SVR halts histological disease progression in the majority of patients and prevents the loss of graft. Although no differences in patient survival appeared in this study, new studies with longer follow-up periods should confirm the positive benefit of SVR on patient survival.

Ancillary