The role of entecavir in preventing hepatitis B recurrence after liver transplantation

Authors


Qiang XIA, Department of Organ Transplantation, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200127, China. Email: xiaqiang@medmail.com.cn

Abstract

OBJECTIVE:  Although hepatitis B recurrence after liver transplantation has been reduced to 0%–10% since the application of the combination therapy of hepatitis B immunoglobulin (HBIG) and lamivudine, the viral mutation resistance of lamivudine is still an obstacle to the outcome of liver transplantation. Here we evaluate the role of entecavir in preventing hepatitis B recurrence after liver transplantation.

METHODS:

Patients who received a liver transplantation for hepatitis B virus (HBV)-related end-stage liver disease in our center from March 2006 to December 2008 were enrolled in this study. All patients received entecavir (0.5 mg orally, daily) or lamivudine (100 mg orally, daily) together with a long-term low dosage of HBIG to prevent hepatitis B recurrence after transplantation. Serum viral markers (HBsAg, anti-HBs, HBeAg, anti-HBc and anti-HBe) and HBV-DNA level were determined.

RESULTS:  Thirty patients receiving entecavir and 90 patients receiving lamivudine were matched with the same age and sex in both groups. No reinfection of hepatitis B was detected in the entecavir group. The hepatitis B surface antigen of patients in the entecavir group became negative within one week and no patient had any adverse effect relating to entecavir. There was no difference in the cumulative survival rate between the entecavir group and the lamivudine group (P > 0.05).

CONCLUSION:  This study shows that entecavir combined with low dosages of HBIG is effective and safe in preventing hepatitis B recurrence after liver transplantation, but its long-term effect is still under investigation and a large-sample study will be carried out in the future.

INTRODUCTION

Hepatitis B infection is a global health problem. It is estimated that there are 300–400 million people chronically infected with hepatitis B virus (HBV) and about 1 million patients die annually from either liver failure or hepatocellular carcinoma.1,2 Currently liver transplantation (LT) is the only effective treatment for HBV-related end-stage liver disease, but in the 1970s chronic hepatitis B (CHB) was still considered a contraindication to LT because of the high recurrence rate of HBV infection which can lead to immediate hepatic failure and death. The use of hepatitis B immunoglobulin (HBIG) has significantly reduced the post-transplantation HBV recurrence rate and therapy has changed the situation. A combination of HBIG and lamivudine (LAM) can further reduce the recurrence rate to <10%, hence, CHB end-stage disease can be reconsidered an indication for LT. Recently the United Network for Organ Sharing reported that patients receiving LAM have a post-transplant prognosis similar to and in some cases better than patients who received a transplant for other non-HBV-related liver diseases.3

Unfortunately, the long-term use of LAM incurs a high resistance rate of HBV (1 year 23%, 2 years 46%, 3 years 55%, 4 years 71%, 5 years 65%),4 and the incidence of developing resistance to LAM monotherapy in LT patients is approximately 10% after 1 year, reaching approximately 50% after 3 years of therapy.5 At present, other nucleotide analogues such as adefovir (ADV) and telbivudine have been used in the treatment of CHB disease. Several studies had revealed that the cumulative probabilities of 5-year genotypical resistance to adefovir in HBeAg negative patients was 29%6 and the 2-year virological breakthrough due to resistance to telbivudine was 21.6% and 8.6% in HBeAg-positive and HBeAg-negative patients, respectively.7 The viral mutation resistance of nucleotide analogues is still an obstacle to the outcome of LT. Therefore, a more effective nucleotide analogue with a lower resistance rate is required to prevent the recurrence of hepatitis B after LT.

A promising candidate is entecavir. In the two phase-III trials, nucleoside-naïve patients with HBeAg-positive or HBeAg-negative CHB receiving entecavir 0.5 mg daily for 48 weeks achieved a superior virology, histological and biochemical efficacy than those who received LAM 100 mg per day.8,9 It has been reported that the lowest rate of resistance of entecavir was only 1.2% in 5 year.10 Shakil et al.11 and Samuelson et al.12 have reported the effect of entecavir therapy in LT recipients with chronic HBV infection. However, all these reports have been in the form of abstracts, and a comprehensive analysis of the effectiveness of entecavir in preventing hepatitis B recurrence after LT is still lacking. This is the main focus of this study.

MATERIALS AND METHODS

Patients

Patients who received LT for HBV-related end-stage liver disease in our center from March 2006 to December 2008 were enrolled in this study. The primary end-point of the study was the recurrence of HBV infection, which was defined as reappearance of both serum HBsAg and HBV-DNA.

Antiviral prophylaxis

Patients receiving entecavir orally 0.5 mg or LAM 100 mg once daily were enrolled in the waiting list for LT.

The low-dosage HBIG strategy was used in our center. In the anhepatic phase 2000 IU HBIG was administrated i.m. to neutralize the serum HBV. Patients continued to received entecavir or LAM plus HBIG 1600 IU post-transplantation daily till the HBsAg became negative and the level of HBsAb was >500 IU/L. After that, 800 IU was administered every week and the HBIG dosage was then adjusted to keep the trough level of HBsAb at ≥500 IU/L for 3 months after LT, then ≥300 IU/L for 3–6 month, ≥200 IU/L for 6–12 month, and ≥100 IU/L after 1 year.

Immunosuppressants

Primary immunosuppressants consisted of tacrolimus or cyclosporin A and prednisone with additional mycophenolate mofetil given in case of necessity. Prednisone was gradually reduced and was withdrawn 6 months post-transplantation.

Monitoring markers

Liver and renal functions were tested daily in the first 4 weeks after LT, then twice a week in the following 4 weeks and once a week thereafter. Serum antigens and antibodies (HBsAg, anti-HBs, HBeAg, anti-HBc and anti-HBe) were tested prior to and four times (day, 1, 3, 5 and 7) in the first week post-transplantation. Thereafter the viral markers were measured by standard commercially assays once a week in the first month after LT and then once a month thereafter. Serum HBV-DNA level was measured by quantitative PCR (the lowest level of detection being 103 copies/mL). A liver biopsy and histological examination were performed if the patient had liver dysfunction.

Statistical methods

Continuous variables were expressed as the median (range), unless specified otherwise. Categorical data were expressed as the number (percentage). Cumulative patient survival was calculated using the Kaplan–Meier method. P-values <0.05 were considered statistically significant.

RESULTS

Overall 372 patients with hepatitis B-related disease underwent LT during the period of March 2006 to December 2008. The latest follow-up was January 2009. Among them, 33 patients received entecavir before and after LT. The patients who switched to LAM or ADV after 1 year's treatment due to its high cost were excluded from the study. A total of 30 patients in the entecavir group (ETV group) remained. As patients receiving LAM were tenfold more than those who received entecavir, we used a case-control study method. Age and sex were the two matching factors between the ETV group and the LAM group (LAM group). One patient in the ETV group was matched with three patients in the LAM group by age and sex. The median age of the patients in the two groups were 48 years in the ETV group (range, 31–70) and 46 years in the LAM group (range, 28–64), P= 0.596. The proportion of male patients in the two groups was 87% (26/30 in the ETV group, 78/90 in the LAM group). All the patients in both groups were HBsAg (+) prior to LT, and 41 were HBeAg-positive (nine in the ETV group, 32 in the LAM group) and 79 were HBeAg-negative or HBeAb-positive (21 in the ETV group, 58 in the LAM group) before transplantation. HBV-DNA was positive in 18 patients at a level ranging from 1.52 × 103 copies/mL to 1.65 × 107 copies/mL in the ETV group and 52 patients at a level ranging from 1.32 × 103 copies/mL to 5.37 × 107 copies/mL in the LAM group. The mean level of HBV-DNA before LT in the ETV group and the LAM group was 1.21 × 107 copies/mL versus 1.39 × 107 copies/mL, P= 0.875. Twenty patients underwent deceased donor orthotopic LT and 10 patients underwent living donor orthotopic LT in the ETV group. The patients' characteristics are shown in Table 1.

Table 1.  Patient characteristics
 Entecavir group (n= 30)Lamivudine group (n= 90)P value
  1. HBV-DNA was regarded as positive if hepatitis B virus-DNA serum level >103 copies/mL. HBV, hepatitis B virus.

  2. P < 0.05.

  3. LDLT, Living donor liver transplantation.

Age, median (range)48 years (31–70)46 years (28–65)0.596
Gender  1.000
 Male/female (%)26/4 (87/13)78/12 (87/13) 
Indication  0.123
 Severe hepatitis (%)5 (17)8 (8.8)
 Liver cirrhosis (%)15 (50)41 (45.6)
 Hepatocellular carcinoma (%)9 (30)41 (45.6)
 Cholangiocellular carcinoma (%)1 (3)0 (0)
HBV-DNA (+) (%)18 (60)52 (58)0.831
HBeAg + (%)9 (30)32 (36)0.578
Operation  0.641
  orthotopic LT/LDLT (%)20/10 (67/33)70/20 (78/22) 

Patients in the ETV group achieved undetectable HBsAg earlier than those in the LAM group (median, 3 days; range, 1–7 days; vs median, 5 days; range, 1–21 days; P= 0.003). The HBV-DNA of those who had positive pre-transplantation were undetectable within 1 week in both groups, P= 0.641. The average HBeAg time of seroconversion was 4 days (range, 1–9 days) in the ETV group and 3 days (range, 1–14 days) in the LAM group, P= 0.356.

Recurrent hepatitis B and HBsAb levels

No HBV reinfection was detected by the time of the latest follow up in the ETV group, but 10 patients were diagnosed as having HBV reinfection in the LAM group (Table 2). Four patients were tested for YMDD mutant, of whom two displayed a LAM-resistant viral YMDD mutant. ADV was added to these four patients and all had undetectable HBsAg. Four patients took entecavir instead of LAM when diagnosed with HBV reinfection. One of the four patients died of severe organ dysfunction 1 month after HBV recurrence. The other three patients died of recurrence of hepatocellular carcinoma. The dosage of HBIG was increased in the remaining two patients and one became HBsAg-negative. The other died of recurrence of hepatocellular carcinoma.

Table 2.  Hepatitis B recurrence
 HBV positive (%)P value
  1. P < 0.05.

Entecavir group0 (0)0.049
Lamivudine group10 (11.1)

The median serum anti-HBs level in the ETV group and the LAM group was 527 IU/L (range, 41.2–1000) and 519 IU/L (range, 0–1000), respectively, at week 1 post-transplantation, 667 IU/L (range, 173–1000) and 706 IU/L (range, 65–1000) at 1 month, and 297 IU/L (range, 55.8–543) and 305 IU/L (range, 75–693) at 12 months post-transplantation (Figs 1,2).

Figure 1.

Plasma HBsAb level versus time in entecavir group.

Figure 2.

Plasma HBsAb level versus time in lamivudine group.

Patient survival

Two patients in the ETV group and one patient in the LAM group died within the first month following transplantation from multi-organ failure. Two patients died later 1 month after post-transplantation in the ETV group: one died of infectious fungal endocarditis and one of multi-organ failure. The other 26 patients are all surviving at the time of writing and are being followed up currently. In the LAM group, nine patients died 1 month after post-transplantation: one patient died of cerebral hemorrhage, one died of severe pneumonia, six had recurrence of disease and one had severe organ dysfunction due to HBV reinfection. There was no difference in the survival rates of the two groups (P= 0.339). The cumulative survival rate of 30 months by Kaplan–Meier in the two groups was 81% for both (Fig. 3).

Figure 3.

Post-transplantation survival in entecavir (ETV) and lamivudine (LAM) groups.

Complications

Biliary complications were present in four patients in the ETV group (one bile leakage, three biliary stricture). One, who was prepared to receive re-transplantation, progressed gradually to hepatic and renal failure, the other three patients recovered after endoscopic retrograde cholangiography treatment. One patient was complicated with a systemic fungal infection after transplantation and he was then treated with antifungal drugs. He was still alive at the last follow up. Another patient had psychological problems for a short period post-transplantation. Acute rejection occurred in one patient and drug-induced liver dysfunction was detected in one patient by liver biopsy. None of these complications were considered related to entecavir.

Biliary complications (n= 17), pneumonia (n= 6), cerebral hemorrhage (n= 1) and liver dysfunction (n= 15) occurred in the LAM group. One patient died of liver failure because of HBV reinfection.

DISCUSSION

China has the largest number of chronic hepatitis B-infected patients in the world. Approximately 112 million Chinese citizens are chronically infected with HBV13. Hepatitis B-related liver disease is the main indication for LT in China. Nevertheless the high recurrence rate of HBV after surgery impedes the progress of LT and the outcome of post-transplantation patients. Without any antiviral prophylaxis, the hepatitis B recurrence rate can be as high as 80–100% after LT. LAM combining with HBIG, which can reduce the recurrence rate to 0–10% in a short time, is the basic antiviral therapy in most LT centers currently. But the prolonged use of LAM therapy often has been accompanied by high rates of virological and biochemical breakthroughs due to lamivudine-resistant mutant HBV strains. Patients with hepatitis B-related disease need to have long-term antiviral therapy after LT. Therefore, the choice of a new nucleotide analogue with a high genetic barrier to resistance is especially important in the outcome of post-transplantation patients.

Entecavir was approved by the US Food and Drug Administration on 29 March 2005 for the treatment of adult patients with chronic HBV infection. Lai et al.9 and Chang et al.8 have proved that entecavir is superior to LAM with regard to histological improvement, virological response and normalization of alanine aminotransferase (ALT) levels in healing both HBeAg-positive and negative naïve patients in two-phase III trails, respectively. Leung et al.14 compared entecavir with ADV in HBeAg-positive CHB patients with a high viral load (the mean baseline HBV-DNA was 10.26 and 9.88 lg10 copies/mL in each group, respectively). The HBV-DNA reduction was significantly greater in the case of entecavir as early as day 10. The ETV group showed a greater reduction in HBV-DNA at week 12 and week 48 than the ADV group (12 weeks, −6.23 vs−4.42 lg10 copies/mL, P < 0.0001; 48 weeks, −7.28 vs−5.08 lg10 copies/mL, respectively). At 48 weeks 58% vs 19% patients achieved undetectable HBV DNA (<300 copies/mL) by PCR, respectively. According to its excellent efficacy and low resistance rate entecavir has been approved as the first-line monotherapy for the treatment of CHB infection in European Association for the Study of the Liver clinical practice guidelines for management of chronic hepatitis B15. On the other hand, the Asian-Pacific Association for the Study of the Liver has pointed out that entecavir could be used as a primary treatment modality in patients with decompensated liver disease.16 However in China many CHB patients are still unwilling to choose entecavir as the first-line therapy because of the relatively high cost of the drug, just like the three patients in our center who finally switched from entecavir to other nucleotide analogues. In terms of the cost effectiveness of entecavir, many studies have reported that entecavir had the lowest median cost per cirrhosis prevented (USD$ 500 000) and cost per hepatocellular carcinomas prevented (USD$ 1.0 million) for full-paying patients.17 Compared to LAM/ADV salvage over 2 years' treatment, entecavir had an incremental cost-effectiveness ratio (ICER) of US$ 7600/quality-adjusted life years (QALY). Compared to adefovir, entecavir had an ICER of US$25 626 per QALY gained.17 Recently Yuan et al.18 evaluated the cost effectiveness of entecavir treatment compared with LAM in China. The authors showed that one year of entecavir therapy produced 0.305 QALY at an incremental cost of 5368 RMB, with a 3% annual discount and using entecavir cost an incremental 17 590 RMB per QALY. Longer term modeling also showed that 3, 5, or 10 years of ETV treatment would still be cost effective, yielding an incremental cost per QALY saved of 44 511, 54 358 and 67 874 in RMB, respectively. Therefore, ETV is more cost-effective in treating hepatitis B patients in the long run.

As regards the use of entecavir in patients after LT, Shail et al.11 assigned nine LT patients failing LAM therapy to receive 1 mg entecavir once daily for a mean duration of 42 weeks (range, 20–67 weeks). The median decrease in HBV-DNA was 1.7, 2.7, 2.8 and 3.0 lg10 at weeks 4, 12, 24 and 36, respectively. Normalization of ALT levels occurred in three patients with baseline ALT > 140 IU/L. The other four patients with ALT < 70 IU/L normalized or continued to have mild elevations by 24 weeks. No viral rebound or hepatitis flare occurred in these patients. Samuelson et al.12 retrospectively assessed the efficacy and tolerability of entecavir in patients following LT. Nine of 68 patients with HBV-related hepatic decompensation received entecavir combined with HBIG after LT. Four patients started on ETV 0.5–1.0 mg daily and an additional five patients switched to ETV due to the suspicion of ADV-induced renal insufficiency. The median post-transplant duration was 10 months (range 4–18 months). Compared with other treatment regimens, ETV demonstrated a lower rate of clinical resistance than LAM (0% vs 12.9%, P= 0.26) and a more favorable adverse effect profile than ADV (0% vs 55.6%, P= 0.047).

Our current data show that all patients who received entecavir as antiviral prophylaxis therapy post-transplantation had good responses. The characteristics of the patients in ETV and LAM groups were statistically the same. Patients with positive HBV-DNA achieved undetectable HBV-DNA within 1 week post-transplantion. The seroconversion of HBsAg occurred within 1 week in patients in the ETV group, which occurred earlier than in the LAM group. The mean level of HBsAb in the ETV group was 297 IU/L at 12 months' post-transplantation, which was higher than the recommended lowest HBsAb level (100 IU/L) for lifelong maintenance.19 The hepatitis B recurrence rate was lower in the ETV group than that in the LAM group (0% vs 11.1%, P= 0.049). It has been demonstrated that entecavir is superior to LAM in preventing hepatitis B recurrence after LT, and yet there was no difference in the cumulative survival rate between ETV group and LAM group. No entecavir-related complications occurred.

In conclusion, our study demonstrates that entecavir is safe and effective in the prevention of hepatitis B recurrence a short time after LT. Our study on the long term effect of entecavir in LT is still in process, and a large-sample study is needed in the future.

ACKNOWLEDGMENT

This research was supported by both Shanghai Science and Technology Committee grant (No. 07JC14040) and key disciplinary field development funding of Shanghai Jiaotong University.

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