Factors associated with the virological response of lamivudine-resistant hepatitis B virus during combination therapy with adefovir dipivoxil plus lamivudine

Long-term outcomes and dynamics of mutants associated with lamivudine-adefovir rescue therapy in patients with lamivudine-resistant chronic hepatitis B

Background/Aims

To investigate the association between the baseline profiles and dynamics of hepatitis B virus (HBV) DNA polymerase gene mutations and the long-term virological response of lamivudine (LAM)-adefovir (ADV) combination therapy in patients with LAM-resistant chronic hepatitis B.

Methods

Seventy-five patients who received LAM-ADV combination therapy for more than 12 months were analyzed. Restriction fragment mass polymorphism assays were used to detect and monitor the dynamics of LAM- and ADV-resistant mutations.

Results

The median duration of LAM-ADV combination therapy was 26 months (range, 12 to 58 months). The baseline mutation profiles, rtM204I (p=0.992), rtM204I/V (p=0.177), and rtL180M (p=0.051), were not correlated with the cumulative virological response, and the baseline HBV DNA level (p=0.032) was the only independent predictive factor for cumulative virological response. Tests for LAM- and ADV-resistant mutations were performed in 12 suboptimal responders in weeks 48 and 96. The population of rtM204 mutants persisted or increased in 8 of 12 patients, and rtA181T mutants newly emerged as a minor population in four patients until 96 weeks. Nevertheless, the viral loads progressively decreased during rescue therapy, and these dynamics did not correlate with virological response.

Conclusions

The baseline profile and dynamics of LAM-resistant mutations during LAM-ADV combination therapy are not associated with a virological response.

Long-term efficacy and emergence of multidrug resistance in patients with lamivudine-refractory chronic hepatitis B treated by combination therapy with adefovir plus lamivudine

BACKGROUND

Few studies have investigated the emergence of multidrug resistance to adefovir dipivoxil (ADV) plus lamivudine (LAM) combination therapy for patients with LAM-refractory chronic hepatitis B (CHB). In this retrospective study, we investigated the long-term clinical course of these patients with or without multidrug resistance mutations.

METHODS

We analyzed 406 Japanese patients with LAM-refractory CHB treated with combination therapy with follow-up for a median of 5.4 (0.5-9.5) years. Multidrug resistance of hepatitis B virus (HBV) DNA was analyzed using direct sequencing or cloning methods at baseline and viral breakthrough or insufficient decline during combination therapy.

RESULTS

Ratio of patients with undetectable serum HBV DNA levels (<2.6 log copies/mL) during combination therapy was 63, 72, 75, 79, 82, 80 and 85 % at years 1 through 7, respectively. Substitutions associated with multidrug resistance were identified in 11 patients (2.7 %) at baseline, and in 12 patients (3 %) during therapy. HBV DNA levels of patients with rtA181S mutation at baseline and emergence of rtA181T + rtN236T double mutation or a wide variety of mutations during combination therapy could not be suppressed. Moreover, using ultra-deep sequencing, rtA181T/V mutations were detected at baseline in 7 of 10 patients with emergent multidrug resistance during combination therapy, although 6 of these 7 patients had very low frequency (<1 %) variants.

CONCLUSION

Long-term ADV plus LAM combination therapy is effective in LAM-refractory patients. However, HBV DNA levels of the patients with multidrug resistance at baseline or during combination therapy sometimes could not achieve complete suppression or were re-elevated after a decrease.

Renal dysfunction and hypophosphatemia during long-term lamivudine plus adefovir dipivoxil therapy in patients with chronic hepatitis B

BACKGROUND

Renal dysfunction and Fanconi's syndrome associated with hypophosphatemia caused by long-term administration of low-dose adefovir dipivoxil (ADV) has been reported in recent years. The aim of this retrospective study was to determine the incidence and factors associated with renal dysfunction and hypophosphatemia in patients with hepatitis B infection on long-term treatment with ADV and lamivudine (LAM).

METHODS

The study subjects were 292 patients treated with 10 mg/day ADV and 100 mg/day LAM for more than 6 months. We evaluated estimated glomerular filtration rate (eGFR), serum creatinine and serum phosphate level at the start of ADV and every 6 months.

RESULT

During a median treatment duration of 64 months, 28 (9.6 %) patients developed renal impairment (defined as eGFR < 50 ml/min/1.73 m(2)), and 73 (27.1 %) developed hypophosphatemia, including 14 with persistent hypophosphatemia. The cumulative incidences of renal impairment at 1, 3, and 5 years were 1.4, 7.5, 10.5 %, respectively, and those of hypophosphatemia were 6.8, 20.6, 26.7 %, respectively. Multivariate analysis identified old age, liver cirrhosis and hypertension as determinants of renal impairment, and male sex, HCC, low baseline serum phosphate as determinants of hypophosphatemia. Three of the 14 patients with persistent hypophosphatemia developed Fanconi's syndrome; their serum creatinine level remained normal, but eGFR was lower than at baseline.

CONCLUSION

Long-term treatment of hepatitis B with low-dose (10 mg/day) ADV and LAM can potentially cause renal impairment and hypophosphatemia. We advocate regular monitoring of serum phosphate and evaluation of eGFR, in addition to serum creatinine, in such patients.

Comparison of clinical outcomes in hepatitis B virus-positive kidney transplant recipients with or without pretransplantation antiviral therapy

BACKGROUND

Antiviral agents have improved the outcomes of hepatitis B virus (HBV)-positive kidney transplant recipients (KTRs). Preemptive therapy has been the main approach to forestall HBV reactivation. We sought to compare prophylactic and preemptive approaches.

METHODS

We divided the 69 HBV-positive KTRs into treatment and historical control groups, according to the time of starting pretransplantation antiviral therapy. The treatment group was further divided into prophylactic and preemptive therapy groups.

RESULTS

The treatment group showed a significant improvement in 10-year graft (82% vs 34%) and patient (91% vs 57%) survivals. Among the historical control group, the main causes of graft failure were patient deaths (68%), which were mostly caused by liver diseases. In contrast, there was no liver-related death in the treatment group. In addition, there was no difference in graft or patient survival between the prophylactic and preemptive groups, but the incidence of HBV reactivation was lower in the prophylactic group. Antiviral therapy was an independent factor for the improved patient survival (P = .005).

CONCLUSIONS

Pretransplantation antiviral therapy is essential to improve clinical outcomes. Prophylactic may be better than preemptive antiviral therapy to decrease HBV reactivation.

HBV DNA level at 24 weeks is the best predictor of virological response to adefovir add-on therapy in patients with lamivudine resistance

BACKGROUND

The aim of this study was to investigate the relationship between HBV DNA levels at baseline and on-treatment and the virological response at 96 weeks after adefovir add-on therapy in chronic hepatitis B (CHB) patients with lamivudine resistance.

METHODS

Lamivudine and adefovir combination therapy was administered to 122 CHB patients for >24 months.

RESULTS

Virological response (HBV DNA negativity) was achieved in 53 (43.3%) and 62 patients (50.8%) at 48 and 96 weeks, respectively. The receiver operating characteristic curve analysis showed that the HBV DNA level at week 24 had a greater power (area under the receiver operating characteristic curve 0.978; 95% CI 0.949, 1.000; P<0.001) to predict the virological response at week 96 of treatment than did the pre-treatment HBV DNA level (area under the receiver operating characteristic curve 0.771; 95% CI 0.640, 0.902; P<0.001). The best cutoff value for the HBV DNA level, at week 24, for the prediction of the virological response at week 96 was 200 IU/ml (3 log(10) copies/ml), with a sensitivity and specificity of 90.3% and 95.0%, respectively. Using this time frame and cutoff value, 56 (90.3%) out of 62 patients that had a virological response at 96 weeks had <200 IU/ml HBV DNA at 24 weeks.

CONCLUSIONS

Although the HBV DNA level at baseline is often used to predict the antiviral potency of lamivudine and adefovir combination treatment in CHB patients with lamivudine resistance, the results of this study suggest that the HBV DNA level at 24 weeks is a better marker for the virological response.

[Add on lamivudine to adefovir monotherapy for the treatment of lamivudine-resistant chronic hepatitis B patients]

BACKGROUND/AIMS

Add on adefovir (ADV) to ongoing lamivudine (LAM) has been recommended as a standard therapy for the treatment of LAM resistance. In the past, switch to ADV monotherapy was suggested as an option for the treatment of LAM resistance, leading to frequent development of ADV resistance. However, ADV monotherapy has been still used in LAM-resistant patients because of low cost in Korea. The aims of this study were to evaluate the virologic response and virologic breakthrough during adding on LAM in LAM-resistant patients receiving ADV monotherapy.

METHODS

The study population comprised 99 patients with LAM-resistance. We divided them into 3 groups (Group 1: switch to ADV monotherapy, N=58, Group 2: add on ADV to ongoing LAM, N=25, Group 3: add on LAM to ADV monotherapy, N=16). HBV DNA levels were assessed at baseline and every 3 months during therapy. Serum HBV DNA levels were measured by bDNA assay or the COBAS TaqMan(TM) HBV test.

RESULTS

The median treatment duration for group 1, group 2, and group 3 was 42.0, 20.6, and 31.8 (18.7 mon. of ADV13.1 mon. of LAM) months, respectively. Cumulative rate of virologic breakthrough in group 1 was 5.2%, 19.0%, and 25.9% at 12, 24, and 36 months of treatment, respectively. Virologic breakthrough was not detected in group 2 and group 3 (p=0.016, group 1 vs. group 2 or 3). In group 3, median serum HBV DNA levels were 4.22 log10 copies/mL prior to LAM administration. Median serum HBV DNA changes from baseline (log10 copies/mL) were -0.91, -1.93, -1.87 and -1.74 at week 12, 24, 36 and 48, respectively.

CONCLUSIONS

Later add on LAM to ADV monotherapy prevented the development of ADV resistance in patients with LAM resistance effectively, comparable to ADV add on to continuing LAM therapy.

Avoiding and managing lamivudine resistance in chronic hepatitis B: current approaches and potential strategies including pegylated interferon

Since its approval for the treatment of chronic hepatitis B in 1998, lamivudine (LAM) has been used extensively throughout the world, because of its relatively low costs and favourable tolerability. However, clinical trials and cohort studies have demonstrated that a high rate of resistance to this drug develops and, as a result, it is no longer included as a first-line therapy in most current treatment guidelines. Nevertheless, because of its low cost, this drug continues to be used in many countries and the pool of patients who have developed resistance to LAM continues to increase. Thus, there is a clear need to develop coherent management strategies to treat such patients as well as limit the emergence of resistance in the first instance. The purpose of this review is to highlight the need to aim for long-term treatment success while limiting the emergence of drug resistance and its consequences for the future. In addition to add-on/switch strategies with other nucleos(t)ide analogs, currently available data suggest that interferon-based therapies, with their potential to induce a sustained response, are worthy of consideration not only for reducing de novo resistance but as an option for the management of those patients in whom drug resistance has already developed.

Development of HCC in patients receiving adefovir dipivoxil for lamivudine-resistant hepatitis B virus mutants

AIM

To identify factors for the development of hepatocellular carcinoma (HCC) in the patients who receive adefovir add-on lamivudine for treatment of lamivudine-resistant hepatitis B virus (HBV) mutants.

METHODS

A total of 247 patients who developed lamivudine-resistant HBV mutants, with an increase of HBV DNA >/= 1 log copies/mL, received adefovir dipivoxil 10 mg add-on lamivudine 100 mg daily during a median of 115 weeks (range: 25-282 weeks). They were followed for the development of HCC by imaging modalities every 3-6 months.

RESULTS

HCC developed in 18 of the 247 (7.3%) patients. Eight factors were in significant association with the development of HCC by the univariate analysis. They included age, cirrhosis, platelet counts, levels of bilirubin, aspartate aminotransferase (AST), alanine aminotransferase and alpha-fetoprotein, as well as YMDD mutants at the start of adefovir dipivoxil. By the multivariate analysis, AST levels, YIDD mutants, cirrhosis and age were independent factors for the development of HCC. By the Kaplan-Meier analysis, AST levels >/= 70 IU/L, YIDD mutants, cirrhosis and age >/= 50 years increased the risk of HCC (P = 0.018, P = 0.035, P = 0.002 and P = 0.014, respectively). HCC developed more frequently in the patients with than without cirrhosis at the start of adefovir (10/59 [16.9%] vs. 8/188 [4.3%], P = 0.002).

CONCLUSION

HCC can develop in cirrhotic patients receiving adefovir add-on lamivudine. Hence, the patients with baseline AST >/= 70 IU/L and YIDD mutants would need to be monitored closely for HCC.

Guidelines for the treatment of chronic hepatitis and cirrhosis due to hepatitis B virus infection for the fiscal year 2008 in Japan

In the 2008 guidelines for the treatment of patients with cirrhosis, who are infected with hepatitis B virus (HBV), the main goal is to normalize levels of alanine and aspartate aminotransferases by eliminating HBV or reducing viral loads. In patients with compensated cirrhosis, the clearance of HBV from serum is aimed for by entecavir, as the main resort, for histological improvement toward the prevention of hepatocellular carcinoma (HCC). In patients with decompensated cirrhosis, by contrast, meticulous therapeutic strategies are adopted for the reversal to compensation, toward the eventual goal of decreasing the risk of HCC. For maintaining liver function and preventing HCC, branched chain amino acids and nutrient supplements are applied, in addition to conventional liver supportive therapies. For patients with chronic hepatitis B, separate guidelines are applied to those younger than 35 years and those aged 35 years or older. Even for patients with chronic hepatitis who are negative for hepatitis e antigen (HBeAg), but who harbor HBV DNA in titers of 7 log copies/mL or more, a "drug-free state" is aimed for by sequential treatment with interferon (IFN) plus entecavir as the first line. For patients with chronic hepatitis B aged 35 years or older, who are HBeAg-negative and carry HBV DNA in titers of less than 7 log copies/mL, long-term IFN for 24-48 weeks is adopted anew. To HBeAg-negative patients who have either or both platelet counts of less than 150 x 10(3)/mm(3) and less than 7 log copies of HBV DNA, also, long-term IFN for 24-48 weeks is indicated.

Factors contributing to antiviral effect of adefovir dipivoxil therapy added to ongoing lamivudine treatment in patients with lamivudine-resistant chronic hepatitis B

PURPOSE

The antiviral effect of adefovir dipivoxil (ADV) added to ongoing lamivudine (LAM) treatment for LAM-resistant chronic hepatitis B (CHB) differs among patients. We investigated clinical factors affecting the response to ADV therapy in LAM-resistant CHB.

METHODS

The subjects were 75 LAM-resistant CHB patients treated with ADV in addition to LAM. Virological response (VR) was defined as HBV DNA clearance (<2.6 logcopies/ml) at 12 months after the start of ADV therapy. Clinical factors contributing to VR were examined by univariate and multivariate analyses.

RESULTS

Lower HBV DNA at baseline and negative hepatitis B e antigen (HBeAg) were significant factors affecting VR in univariate analysis. In multivariate analysis, lower HBV DNA at baseline (P = 0.005), negative HBeAg (P = 0.009), and higher ALT (P = 0.036) were significant independent factors contributing to VR. In HBeAg-positive patients, HBV DNA clearance was more frequently observed during ADV therapy in patients with baseline HBV DNA < or = 7.0 logcopies/ml than in those with baseline HBV DNA >7.0 logcopies/ml. By contrast, the link of lower HBV DNA at baseline to better therapeutic response was not evident in HBeAg-negative patients.

CONCLUSION

In ADV therapy added to ongoing LAM treatment for LAM-resistant CHB, lower baseline HBV DNA and negative HBeAg contributed to a better antiviral effect. Addition of ADV should be done promptly before marked increase in HBV DNA, especially in CHB patients showing LAM resistance positive for HBeAg.

Combination of baseline parameters and on-treatment hepatitis B virus DNA levels to start and continue patients with lamivudine therapy

BACKGROUND

This study aimed to identify the baseline hepatitis B virus (HBV) DNA, alanine aminotransferase (ALT) levels and on-treatment HBV DNA levels for favourable outcome in patients receiving 5-year lamivudine.

METHODS

Virological, serological and biochemical parameters were assessed in 74 hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) patients at year 5 of therapy.

RESULTS

Patients with baseline HBV DNA levels <9 log(10) copies/ml and ALT> or =2x the upper limit of normal (ULN) had a significantly higher chance of HBV DNA suppression to <4 log(10) copies/ml (76.5%) and HBeAg seroconversion (82.4%), and a lower chance of YMDD mutations (35.3%) compared with patients with HBV DNA<9 log(10) copies/ml and ALT<2xULN and patients with HBV DNA> or =9 log(10) copies/ml (all P<0.05). All patients with these two baseline parameters plus week 4 HBV DNA<4 log(10) copies/ml achieved HBV DNA<35 copies/ml, HBeAg seroconversion and ALT normalization without YMDD mutations at year 5. When these two baseline parameters were combined with week 24 HBV DNA<3 log(10) copies/ml, 60%, 80% and 90% of patients had HBV DNA<35 copies/ml, <3 log(10) copies/ml and <4 log(10) copies/ml, respectively at year 5. Overall, 90% of patients had HBeAg seroconversion and only 10% had YMDD mutations.

CONCLUSIONS

For HBeAg-positive patients with baseline HBV DNA<9 log(10) copies/ml and ALT> or =2xULN, lamivudine could be initiated. For those with HBV DNA<4 log(10) copies/ml at week 4 or <3 log(10) copies/ml at week 24, continuation of lamivudine treatment would be more likely to result in a good long-term response.