Cost-effectiveness analysis of lamivudine and adefovir dipivoxil in the treatment of patients with HBeAg-negative chronic hepatitis B

Are Published Health Economic Models for Chronic Hepatitis B Appropriately Capturing the Benefits of HBsAg Loss? A Systematic Literature Review

OBJECTIVES

Sustained hepatitis B surface antigen (HBsAg) loss or 'functional cure' (FC) is considered an optimal treatment endpoint by international clinical guidelines for chronic hepatitis B (CHB), yet rarely is this achieved with current standard of care (SoC). This leads to an under-reporting of FC in clinical trials, observational studies and health economic (HE) models. This paper systematically identifies and assesses how FC is incorporated in published HE models of CHB.

METHODS

A systematic literature review was conducted in PubMed and Embase (conducted February 2019) to review how HBsAg loss is captured in HE models. The following items were extracted: rate of (and transition probabilities to) HBsAg loss, HBsAg loss health state costs, and HBsAg loss health state utilities.

RESULTS

Sixty-five economics evaluations were identified, and < 50% of these (27/65) incorporated HBsAg loss in their models. Only 15/27 stated HBsAg loss health state costs, 15/27 stated HBsAg loss health state utilities, and 11/27 mentioned treatment-specific transition probabilities to HBsAg loss. The majority of sources these inputs were derived from are not transparent.

CONCLUSIONS

The benefits of FC in current HE models are not well captured, as FC is often not reported or not directly related to modelled treatments. This has the potential for novel agents with higher efficacy compared with SoC to be overlooked and undervalued if their worth is not appropriately communicated. In order to ensure optimal access for patients to new and effective therapies, it is important that the benefits of FC are better assessed and captured within HE models.

Adefovir dipivoxil is less expensive than lamivudine and associated with similar prognosis in patients with hepatitis B virus-related hepatocellular carcinoma after radical resection

Aim

Lamivudine (LAM) and adefovir dipivoxil (ADV) are widely used in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC), but few studies have directly compared their therapeutic efficacy and treatment cost. This study aims to compare LAM with ADV head-to-head in these patients.

Methods

We retrospectively analyzed 201 patients with HBV-related HCC who underwent radical resection and subsequently received LAM (n=155) or ADV (n=46). The two groups were compared in terms of HBV-DNA levels, liver function, antiviral resistance, recurrence-free, and overall survival, as well as antiviral medication costs.

Results

Despite significant improvement in HBV-DNA and alanine aminotransferase level in the LAM group after 1 year of antiviral therapy, these parameters did not differ significantly between the two groups over the following 2 years. Incidence of antiviral resistance after 1, 2, and 3 years of antiviral treatment was significantly higher in the LAM group (19.5%, 45.7%, and 56.4%) than in the ADV group (0%, 3.3%, and 14.5%; P<0.001). Overall survival at 1, 2, and 3 years after resection was similar for the LAM group (84.5%, 69.3%, and 64.6%) and the ADV group (84.1%, 77.8%, and 63.4%; P=0.905). Recurrence-free survival at the three follow-up points was also similar for the LAM group (71.7%, 58.3%, and 43.9%) and the ADV group (81.1%, 66.1%, and 53.0%; P=0.452). Cox regression analysis confirmed that both nucleos(t)ide analogues were associated with similar overall and recurrence-free survival. However, the average medication costs after 1, 2, and 3 years of antiviral treatment were significantly higher in the LAM group (€3.0, €4.8, and €5.6 per person per day) than in the ADV group (€2.2, €2.4, and €3.1 per person per day; all P<0.05).

Conclusion

ADV and LAM are associated with similar survival benefit in patients with HBV-related HCC after radical resection, but ADV is more cost-effective.

A cost-utility analysis of drug treatments in patients with HBeAg-positive chronic hepatitis B in Thailand

BACKGROUND

Only lamivudine has been included for patients with chronic hepatitis B (CHB) in the National List of Essential Drugs (NLED), a pharmaceutical reimbursement list in Thailand. There have also been no economic evaluation studies of CHB drug treatments conducted in Thailand yet. In order to fill this gap in policy research, the objective of this study was to compare the cost-utility of each drug therapy (Figure 1) with palliative care in patients with HBeAg-positive CHB.

METHODS

A cost-utility analysis using an economic evaluation model was performed to compare each drug treatment for HBeAg-positive CHB patients. A Markov model was used to estimate the relevant costs and health outcomes during a lifetime horizon based on a societal perspective. Direct medical costs, direct non-medical costs, and indirect costs were included, and health outcomes were denoted in life years (LYs) and quality-adjusted life years (QALYs). The results were presented as an incremental cost effectiveness ratio (ICER) in Thai baht (THB) per LY or QALY gained. One-way sensitivity and probabilistic sensitivity analyses were applied to investigate the effects of model parameter uncertainties.

RESULTS

The ICER values of providing generic lamivudine with the addition of tenofovir when drug resistance occurred, generic lamivudine with the addition of tenofovir based on the road map guideline, and tenofovir monotherapy were -14,000 (USD -467), -8,000 (USD -267) , and -5,000 (USD -167) THB per QALY gained, respectively. However, when taking into account all parameter uncertainties in the model, providing generic lamivudine with the addition of tenofovir when drug resistance occurred (78% and 75%) and tenofovir monotherapy (18% and 24%) would yield higher probabilities of being cost-effective at the societal willingness to pay thresholds of 100,000 (USD 3,333) and 300,000 (USD 10,000) THB per QALY gained in Thailand, respectively.

CONCLUSIONS

Based on the policy recommendations from this study, the Thai government decided to include tenofovir into the NLED in addition to generic lamivudine which is already on the list. Moreover, the results have shown that the preferred treatment regimen involves using generic lamivudine as the first-line drug with tenofovir added if drug resistance occurs in HBeAg-positive CHB patients.

[Evaluation of the costs of transient elastography (FibroScan(®)) in the diagnosis of liver fibrosis in HIV patients with hepatitis C virus]

INTRODUCTION

The assessment of liver fibrosis is crucial for taking therapeutic decisions in patients infected with HIV/AIDS coinfected with HCV, because it allows the prognosis of the disease and the prioritization of hepatitis C treatment in these patients.

METHODS

A discrete events model simulation (DEMS) and a Markov model have been developed to represent the evolution of liver fibrosis to cirrhosis in patients coinfected with HIV/HVC. The model evaluated two alternatives for the diagnosis and monitoring of these patients, transient elastography performed annually and liver biopsy performed every seven years. The models have been developed under Health Care System perspective and only considered direct medical costs (disease treatment and health state costs). One-way sensitivity analyses were carried out to assess the impact of parameters with higher uncertainty. A discount rate of 3% was applied.

RESULTS

Base case analysis shows that the diagnosis and monitoring of patients with transient elastography is a dominant strategy compared with to liver biopsy, resulting in greater life expectancy at lower cost. The sensitivity analysis performed confirmed the robustness of these results.

CONCLUSION

Transient elastography has proved to be a dominant strategy compared to liver biopsy in the diagnosis and monitoring of liver fibrosis in patients coinfected with HIV/HCV in Spain.

Management options for lamivudine-resistant chronic hepatitis B patients with suboptimal virological suppression by adefovir

BACKGROUND

In chronic hepatitis B (CHB) patients, adefovir is commonly used as a rescue therapy for lamivudine resistance, but often results in incomplete virological suppression.

AIM

To study the factors predicting response to adefovir rescue, and the treatment response of tenofovir and entecavir in suboptimal responders to adefovir in CHB patients.

METHODS

Chronic hepatitis B patients who took adefovir for at least 6 months for lamivudine resistance were studied. Early virological response was defined as undetectable HBV DNA at month 6. Maintained virological response was defined as undetectable HBV DNA till the last follow-up.

RESULTS

Among 136 patients on adefovir for 39 (5-117) months, 30 (22%) had early virological response. The 3-year cumulative probability of maintained virological response was similar between patients on adefovir monotherapy (n = 53, 57.9%) and those on combination of lamivudine and adefovir treatment (n = 83, 56.5%). The month 6 HBV DNA was the only independent factor associated with maintained virological response (adjusted hazard ratio 0.49, 95% confidence interval 0.37-0.65, P < 0.001). Twenty-six of 30 (87%) early responders and 36 of 106 (34%) non-early responders had maintained virological response on adefovir (P < 0.001). Among 106 non-early responders, 18 and 11 were switched to tenofovir and entecavir, respectively. The 1-year cumulative probability of maintained virological response was higher in patients switched to tenofovir (87.5%) than those switched to entecavir (37.5%; P = 0.048) or continued with adefovir (8.7%; P < 0.001).

CONCLUSIONS

In adefovir rescue for lamivudine resistance, month 6 HBV DNA predicts maintained virological response in CHB patients. Switching to tenofovir achieved best viral suppression among suboptimal responders to adefovir.

Modeling the cost-effectiveness of different oral antiviral therapies in patients with chronic hepatitis B

BACKGROUND/AIMS

Chronic hepatitis B (CHB) is a common disease associated with high morbidity, mortality and impact on healthcare costs. Several oral antiviral therapies can lead to complete virologic response, which is associated with prevention of disease progression. The aim of this study was to estimate the cost-effectiveness of the oral antiviral treatments lamivudine, adefovir, telbivudine, entecavir and tenofovir, in patients with CHB.

METHODS

A Markov model was used to project the lifetime complications and costs in cohorts of both HBeAg-positive and HBeAg-negative CHB patients treated with one of the above drugs or no treatment. Rescue therapy with two different combination therapies (adefovir plus lamivudine or tenofovir plus entecavir) with their corresponding costs and efficacy rates was also considered. The probabilities of disease progression were based on serum HBV DNA levels. Disease and complication costs were assessed using the perspective of the Spanish National Health System.

RESULTS

The highest rate of virologic response was obtained with tenofovir, and this translated to its higher life years saved (LYS) and quality adjusted life years (QALY) compared with the rest of the alternatives in HBeAg-positive and HBeAg-negative patients. Tenofovir is associated with lower costs and higher efficacy over entecavir, telbivudine and adefovir in HBeAg-positive patients, and telbivudine and entecavir in HBeAg-negative patients. The incremental cost-effectiveness ratios with respect to the rest of the alternatives are below the common reference efficiency threshold of 30,000 euro per LYS/QALY.

CONCLUSION

In chronic HBV infected patients, tenofovir is a cost-effective or even cost-saving strategy compared with other available treatment options for CHB.

Cost-effectiveness analysis of switching antipsychotic medication to long-acting injectable risperidone in patients with schizophrenia : a 12- and 24-month follow-up from the e-STAR database in Spain

BACKGROUND

The availability of long-acting injectable risperidone may increase adherence to antipsychotic treatment and lead to improved clinical and economic outcomes for patients with schizophrenia.

OBJECTIVES

To investigate the cost effectiveness of treatment with long-acting injectable risperidone compared with previous antipsychotic regimens in patients with schizophrenia enrolled in the electronic Schizophrenia Treatment Adherence Registry (e-STAR) in Spain.

METHODS

e-STAR is an international, long-term, ongoing, observational study of schizophrenia patients who, during their routine course of clinical practice, are started on a new antipsychotic treatment. In e-STAR, data are collected at baseline, retrospectively over a minimum period of 12 months and up to a maximum of 24 months, and prospectively at 3-month intervals for 24 months after the start of a new antipsychotic drug. For the purpose of this study, patients who started treatment with long-acting injectable risperidone during their routine clinical management and were enrolled in the e-STAR study in Spain were eligible. The effectiveness of long-acting injectable risperidone compared with previous antipsychotic treatment, defined as the absence of hospitalizations or relapses, was assessed at 12 and 24 months of treatment. Acquisition costs of antipsychotic drug therapy were based on the official registered price. Drug prices from source were in euro, year 2005 values; hospital costs from source were in euro, year 2001 values, and were inflated to reflect 2005 costs. Complete follow-up data were available for 788 patients at 12 months after starting long-acting injectable risperidone and for 757 patients at 24 months.

RESULTS

In terms of effectiveness, at 12 months after switching to long-acting injectable risperidone, there was a higher percentage of patients who did not require hospitalization (89.1%), did not relapse (85.4%) or neither required hospitalization nor relapsed (82.4%) as compared retrospectively with the same period for the previous treatment (67%, 47.8% and 59.8%, respectively). The corresponding figures at 24 months also favoured treatment with long-acting injectable risperidone (85.2% vs 60%, 88.5% vs 47.4% and 77% vs 53.6%, respectively). Treatment with long-acting injectable risperidone was associated with higher medication costs per month compared with previous antipsychotic medication after 12 (euro 405.80 vs euro 128.16) and 24 months (euro 407.33 vs euro 142.77) of follow-up. Cost effectiveness per month per patient was lower for risperidone than previous antipsychotic medication in the three patient scenarios: without hospitalization (euro 539.82 vs euro 982.13), without relapse (euro 519.67 vs euro 1242.03) and without hospitalization and without relapse (euro 597.22 vs euro 1059.39).

CONCLUSIONS

Treatment with long-acting injectable risperidone compared with previous antipsychotic medications resulted in a higher number of patients not requiring hospitalization, not relapsing, and not requiring hospitalization and not showing relapse, resulting in risperidone being more cost effective per month per patient.It is important to note that real-world variations in adherence would automatically be controlled from within a randomized control trial, and hence, any evaluation of variations in adherence inevitably requires a real-world focus. On the basis of these findings, which were obtained in real-world clinical practice, long-acting injectable risperidone is predicted to be the dominant strategy because it results in effective symptom control and direct medical cost savings. However, because of limitations in methodology, any conclusions should, at this stage, be treated as tentative, and confirmation in more detailed follow-up studies is required. Cost-effectiveness comparisons based on experimental evaluations of relapse minimization strategies are also required. In order to avoid estimation biases in the future, a prospectively designed study is needed.

Therapeutic strategies in the management of patients with chronic hepatitis B virus infection

Currently available options for the treatment of chronic hepatitis B virus (HBV) infection include standard and pegylated interferon alfa and four oral antiviral agents (lamivudine, adefovir, entecavir, and telbivudine). These treatment strategies are either therapies of finite duration that aim to achieve sustained off-therapy responses, or long-term treatments that aim to maintain on-therapy remission. Pegylated interferon alfa may offer higher sustained off-therapy responses after 1 year, but most patients do not respond. Oral antivirals are the only candidates for long-term treatment of patients with chronic HBV infection. Viral suppression has favourable effects on patients' outcome and modifies the natural history of the disease. Viral resistance is the main drawback of long-term antiviral therapy. Lamivudine monotherapy is associated with higher resistance (year 1, 10-27%; year 2, 37-48%; year 4, 60-65%) than adefovir (year 1, 0%; year 2, 3%; year 5, 29%) or telbivudine (year 1, 3-4%; year 2, 9-22%). Entecavir resistance is rare in naive individuals (year 4, <1%), but increases over time in lamivudine-resistant patients (year 4, 43%). The best strategy for long-term therapy in chronic HBV infection has yet to be established.

Economics of chronic hepatitis B and hepatitis C

Although not all patients develop progressive liver disease, chronic hepatitis B and chronic hepatitis C infections cause substantial morbidity and mortality worldwide. To address this need, many new antiviral treatments have become available over the past 10 years. While safety, efficacy, and therapeutic indications have been well established for these agents, the economics of antiviral treatment have become increasingly a focus of discussion for physicians, policymakers, and health payers. In this paper, we will elucidate some economic principles using examples from the treatment of hepatitis B and C. In particular, we will examine the considerations in estimating drug costs, methods for performing economic analyses and lastly summarize published cost-effectiveness analyses for antiviral treatments of chronic hepatitis B and chronic hepatitis C. This review should help clinicians understand economic issues regarding new drugs and answer questions about whether the clinical benefit provided by a medication justifies its expense.

Comparative cost-effectiveness of antiviral therapies in patients with chronic hepatitis B: a systematic review of economic evidence

BACKGROUND AND AIM

Economic efficiency of the alternative antiviral therapies for chronic hepatitis B has not been systematically investigated and their quality remains unknown. The aim of the present study was to systematically overview economic evidence of antiviral therapies for chronic hepatitis B.

METHODS

We searched six databases and eight major journals supplemented with screening references of eligible studies. Full economic evaluations comparing alternative antiviral therapies in patients with chronic hepatitis B virus infection were included. Two investigators assessed the study quality and transferability, independently. Data were analyzed qualitatively with adjustment when appropriate.

RESULTS

Fourteen studies (six modeling vs eight trials and database analyses) were included. Quality was high in five studies, moderate in one US and five Chinese studies, and low in three Chinese studies. The major problems of quality are costing methods and analysis and the presentation of results. In Australia and Poland, lamivudine-preferred strategies dominated interferon (IFN)-alpha and its related strategy from the health-care sector perspective. In the US, adefovir salvage produced US$8446 per additional quality-adjusted life years (QALY) compared with IFN-alpha. In Spain, the cost of adefovir was US$34,840 for additional virological response. In Taiwan, the use of pegylated IFN-alpha (pegIFN-alpha) produced US$11,711.4 per additional QALY, compared with lamivudine. In China, the incremental cost-effectiveness ratios of combination therapy lamivudine ranged from US$2860 to US$22,160 per additional loss of hepatitis B e antigen (HBeAg), and IFN-alpha versus lamivudine ranged from US$2490 to US$8890 per additional loss of HBeAg.

CONCLUSION

The cost-effectiveness frontiers of treatment alternatives vary and are influenced by the comparators and socioeconomic conditions of countries. Lamivudine-containing therapy is cost-effective when newer antiviral agents (e.g. adefovir/pegIFN-alpha) were not available. Economic methods should be further improved in studies, particularly in China.

A systematic review and economic evaluation of adefovir dipivoxil and pegylated interferon-alpha-2a for the treatment of chronic hepatitis B

Standard treatments for chronic hepatitis B (CHB) include interferon-alpha (IFN-alpha) and lamivudine (LAM), but these are associated with adverse effects and viral resistance, respectively. The aim of this systematic review and economic evaluation was to assess the clinical effectiveness and cost-effectiveness of two alternative drugs for the treatment of adults with CHB: adefovir dipivoxil (ADV) and pegylated IFN-alpha-2a. We searched electronic databases, including Cochrane Systematic Reviews and Medline, for literature that met criteria defined in a research protocol. Retrieved articles were independently assessed for inclusion by two reviewers. We developed a Markov state transition model to estimate the cost-effectiveness (cost-utility) of pegylated IFN-alpha-2a and of ADV compared with nonpegylated IFN-alpha-2a, LAM and best supportive care. Seven randomized controlled trials and two systematic reviews met the inclusion criteria for our review of clinical effectiveness. ADV was significantly more effective than placebo or ongoing LAM in reducing levels of hepatitis B virus (HBV) DNA. Rates of hepatitis B e antigen (HBeAg) seroconversion were higher among patients receiving ADV than either placebo or ongoing LAM. Patients treated with pegylated IFN-alpha-2a, either as monotherapy or in combination with LAM, showed significantly reduced HBV DNA levels compared with patients treated with LAM monotherapy. HBeAg seroconversion rates at follow-up were significantly higher for pegylated IFN-alpha-2a patients than for those receiving LAM monotherapy. Results of our cost-effectiveness analysis demonstrate that incremental costs per quality adjusted life year (QALY) for a range of comparisons were between 5,994 and 16,569 British Pound, and within the range considered by NHS decision-makers to represent good value for money.

Treatment of chronic hepatitis B: efficacy of current drugs and prospects for the future

Chronic hepatitis B is an important clinical problem often leading to severe complications. In this review, the results obtained in the last few years with the use of current drugs, such as interferon and nucleo(t)side analogues, are summarized and the problems of obtaining a sustained remission, which is only achieved in a small number of patients, are discussed. The new approaches, such as the use of combinations of drugs, to optimize long-term tolerable treatment are also considered.

Where does adefovir stand amongst newly developed antivirals: from pharmacology to virology

Adefovir, an acyclic nucleotide analog of adenosine monophosphate, has demonstrated potent activities against several viruses in vitro. Since 2002, the diester prodrug of this molecule, adefovir dipivoxil, has been approved as a well-tolerated and efficacious treatment for chronic hepatitis B. It is the first nucleotide analog to be approved for this indication and it is now challenged by several other molecules that also inhibit hepatitis B virus replication. In this article, we analyze the strengths and limitations of adefovir in the context of hepatitis B treatment and consider the other alternatives in the treatment of this difficult-to-treat chronic disease. Adefovir dipivoxil has offered a real opportunity for patients who developed lamivudine resistance and were facing a therapeutic deadlock; the next challenge for clinicians will be to offer the best therapeutic strategy to limit the inexorable selection of resistant strains.