Peginterferon alfa and ribavirin for chronic hepatitis C in patients eligible for shortened treatment, re-treatment or in HCV/HIV co-infection: a systematic review and economic evaluation.

OBJECTIVE: to assess the clinical effectiveness and cost-effectiveness of peginterferon alfa and ribavirin for the treatment of chronic hepatitis c virus (HCV) in three specific patient subgroups affected by recent licence changes: those eligible for shortened treatment courses [i.e. those with low viral load (LVL) and who attained a rapid virological response (RVR) at 4 weeks of treatment], those eligible for re-treatment following previous non-response or relapse, and those co-infected with human immunodeficiency virus (HIV). DATA SOURCES: Fourteen electronic bibliographic databases, including the Cochrane Library, MEDLINE and EMBASE, were searched up to October 2009. Key hepatitis C resources and symposia, bibliographies of related papers and manufacturer submissions to the National Institute for Health and Clinical Excellence were also searched and clinical experts were contacted. REVIEW METHODS: A systematic review and economic evaluation were carried out. Titles and abstracts were screened for eligibility by one reviewer. Inclusion criteria were defined a priori and applied independently by two reviewers to the full text of retrieved references. For the clinical effectiveness review, studies were included if they were randomised controlled trials (RCTs) of adults with chronic HCV, restricted to the patient groups described above. The intervention was standard peginterferon and ribavirin combination therapy compared with shortened duration courses (24 weeks for genotype 1, 16 weeks for genotype 2/3) or best supportive care (BSC). Outcomes included sustained virological response (SVR), relapse rate and adverse events. In addition, full economic evaluations and studies of health-related quality of life were sought for this subgroup of patients. Data extraction and quality assessment were undertaken by two reviewers independently. Studies were synthesised through a narrative review with tabulation of results. Our previously published Markov state-transition model was adapted to estimate the cost-effectiveness of treatment strategies in subgroups of adults with chronic HCV who were eligible for shortened treatment and re-treatment and those with HCV/HIV co-infection. The model extrapolated the impact of SVR on life expectancy, quality-adjusted life expectancy and lifetime costs for each subgroup of patients with HCV. Categories of costs included in the model were drug acquisition, patient management, on-treatment monitoring, management of adverse events, and health-state costs for disease progression. RESULTS: In total, 2400 references were identified. Six RCTs were included in the review of clinical effectiveness, all reporting peginterferon alfa and ribavirin therapy in patients eligible for shortened treatment. In general, these RCTs were of good quality. No RCTs comparing peginterferon and ribavirin with BSC were identified for the re-treatment or co-infection populations. The results suggest that chronic HCV patients who have LVL at baseline and who achieve an RVR can be treated with shortened courses of therapy (24 weeks for genotype 1, 16 weeks for genotype 2/3) and achieve SVR rates that are comparable to those who receive the standard duration of treatment (ranges 84%-96% vs 83%-100%, respectively). However, patient numbers in the LVL/RVR subgroups were small and none of the trials was powered for this subgroup analysis, so results should be interpreted with caution. In the one trial reporting virological relapse rates in the subgroup of patients with LVL/RVR, rates were low and not statistically significantly different between those treated for 24 versus 48 weeks [3.6% vs 0%, respectively, difference 3.6%, 95% confidence interval (CI) -7.2% to 6.6%, p = 1.000]. In the cost-effectiveness analysis of shortened treatment with peginterferon alfa-2a, incremental cost-effectiveness ratios (ICERs) ranged from £35,000 to £65,000 for patients with genotype 1, whereas in patients with genotypes 2 and 3 shortened treatment dominated standard treatment. For patients with genotype 1 with LVL/RVR, shortened treatment with peginterferon alfa-2b dominated standard treatment. In patients with genotype 1 and those with genotype non-1 who were re-treated with peginterferon alfa-2a, the ICERs were £9169 and £2294, respectively. In patients with genotypes 1 and 4, who were re-treated with peginterferon alfa-2b, the ICER was £7681, whereas re-treatment dominated BSC for patients with genotypes 2 and 3. In patients co-infected with HCV/HIV, who were receiving peginterferon alfa-2a, the ICER was £7941 per quality-adjusted life-year (QALY) gained in patients with genotypes 1 and 4, whereas in patients with genotypes 2 and 3 peginterferon alfa-2a dominated BSC. In co-infected patients receiving peginterferon alfa-2b the ICER was £11,806 in genotypes 1 and 4, and £2161 in genotypes 2 and 3. CONCLUSIONS: The clinical trial evidence indicates that patients may be successfully treated with a shorter course of peginterferon combination therapy without compromising the likelihood of achieving an SVR. The economic evaluation shows that treatment with peginterferon alfa in the specified subgroups of patients with LVL/RVR will yield QALY gains, without excessive increases in costs, and may be cost saving in some situations. However, a judgement is required on the value of the QALY loss that may result from adopting a shorter treatment regimen, if shorter treatment is associated with a lower SVR than standard treatment duration. There is a need for further RCT evidence, particularly in people who have not responded to, or relapsed following, treatment. Phase II and Phase III trials are currently in progress, evaluating the safety and efficacy of protease inhibitors and nucleoside analogues for treatment-naive and treatment-experienced people with chronic HCV. FUNDING: The National Institute for Health Research Health Technology Assessment programme.