An Innovative Approach to Modelling the Optimal Treatment Sequence for Patients with Relapsing-Remitting Multiple Sclerosis: Implementation, Validation, and Impact of the Decision-Making Approach.

INTRODUCTION: An innovative computational model was developed to address challenges regarding the evaluation of treatment sequences in patients with relapsing-remitting multiple sclerosis (RRMS) through the concept of a 'virtual' physician who observes and assesses patients over time. We describe the implementation and validation of the model, then apply this framework as a case study to determine the impact of different decision-making approaches on the optimal sequence of disease-modifying therapies (DMTs) and associated outcomes. METHODS: A patient-level discrete event simulation (DES) was used to model heterogeneity in disease trajectories and outcomes. The evaluation of DMT options was implemented through a Markov model representing the patient's disease; outcomes included lifetime costs and quality of life. The DES and Markov models underwent internal and external validation. Analyses of the optimal treatment sequence for each patient were based on several decision-making criteria. These treatment sequences were compared to current treatment guidelines. RESULTS: Internal validation indicated that model outcomes for natural history were consistent with the input parameters used to inform the model. Costs and quality of life outcomes were successfully validated against published reference models. Whereas each decision-making criterion generated a different optimal treatment sequence, cladribine tablets were the only DMT common to all treatment sequences. By choosing treatments on the basis of minimising disease progression or number of relapses, it was possible to improve on current treatment guidelines; however, these treatment sequences were more costly. Maximising cost-effectiveness resulted in the lowest costs but was also associated with the worst outcomes. CONCLUSIONS: The model was robust in generating outcomes consistent with published models and studies. It was also able to identify optimal treatment sequences based on different decision criteria. This innovative modelling framework has the potential to simulate individual patient trajectories in the current treatment landscape and may be useful for treatment switching and treatment positioning decisions in RRMS.

Mapping EQ-5D-3L to EQ-5D-5L.

OBJECTIVES: The original 3-level EQ-5D (EQ-5D-3L) includes 5 dimensions with 3 levels of problems per dimension. Since 2010, a more sensitive version with 5 levels of problems per dimension (EQ-5D-5L) has become available. Population value sets have been developed for both versions of the questionnaire. The objective of this research was to develop a mapping function to link EQ-5D-3L responses to value sets for the EQ-5D-5L. METHODS: Various algorithms were developed to link EQ-5D-3L and EQ-5D-5L responses using data from an observational study including members of 10 subgroups (N = 3580) who completed both versions of the questionnaire. Nonparametric and ordinal logistic regression models were fit to the data and compared using Akaike's information criterion (AIC) as well as the mean absolute error and root mean squared error of predictions. Results were contrasted qualitatively and quantitatively with those of an alternative copula-based approach. RESULTS: Including indicants of problems for other EQ-5D-3L dimensions as regressors in the modeling yielded the greatest improvement in prediction accuracy. Adding age and gender lowered the AIC without improving predictions, while including a latent factor lowered the AIC further and slightly improved predictive accuracy. Models that conditioned on problems in other EQ-5D-3L dimensions yielded more accurate predictions than the alternative copula-based approach in subgroups defined by age and gender. CONCLUSION: We present novel algorithms to map EQ-5D-3L responses to EQ-5D-5L value sets. The recommended approach is based on an ordinal logistic regression that disregards age and gender and accounts for unobserved heterogeneity using a latent factor.

Cost-effectiveness of edoxaban compared to warfarin for the treatment and secondary prevention of venous thromboembolism in the UK.

Background: Venous thromboembolism (VTE), which includes pulmonary embolism (PE) and deep vein thrombosis (DVT), is the third most common acute cardiovascular disease and represents an important burden for patients and payers. Objective: The aim was to estimate the cost-effectiveness of edoxaban, a non-VKA oral anticoagulant vs. warfarin, the currently most prescribed treatment for VTE in the UK. Study design: A Markov model was built using data from the Hokusai-VTE randomised controlled trial to estimate the lifetime costs and quality-adjusted life years (QALYs) in patients with VTE treated with edoxaban or warfarin over a lifetime horizon, from the UK National Health Services perspective. The model included VTE recurrences, VTE-related complications (post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension), and several types of bleeds associated with anticoagulation treatment. Patients were treated during a period of 6 months after the first VTE event, followed by flexible treatment duration (from 6 months to lifetime) after recurrence, i.e., tertiary prevention. Results: Edoxaban was found dominant vs. warfarin with 0.033 additional QALY and £55 less costs. The reduction of patient management costs, specifically monitoring costs, outweighed the higher drug costs. Edoxaban was dominant in all subgroups (index DVT only, all PE cases (PE with or without DVT), PE without DVT and PE with DVT). Cost-savings ranged from £54 to £81 while additional QALYs ranged from 0.031 to 0.046. Edoxaban was found dominant in 88.6% of cases and cost-effective in additional 10.9% of cases considering a £20,000 threshold in the probabilistic sensitivity analysis. Conclusion: Edoxaban may improve patients' quality of life in a lifetime horizon without additional costs for the healthcare system due to lower bleeding risk and no monitoring cost compared to warfarin.

The Importance of Economic Perspective and Quantitative Approaches in Oncology Value Frameworks of Drug Selection and Shared Decision Making.

The debate around value in oncology drug selection has been prominent in recent years, and several professional bodies have furthered this debate by advocating for so-called value frameworks. Herein, we provide a viewpoint on these value frameworks, emphasizing the need to consider 4 key aspects: (1) the economic underpinnings of value; (2) the importance of the perspective adopted in the valuation; (3) the importance of the difference between absolute and relative measures of risk and measuring patient preferences; and (4) the recognition of multiple quality-of-life (QoL) domains, and the aggregation and valuation of those domains, through utilities within a multicriteria decision analysis, may allow prioritization of QoL above the tallying of safety events, particularly in a value framework focusing on the individual patient. While several frameworks exist, they incorporate different attributes and-importantly-assess value from alternative perspectives, including those of patients, regulators, payers, and society. The various perspectives necessarily lead to potentially different, if not sometimes divergent, conclusions about the valuation. We show that the perspective of the valuation affects the framing of the risk/benefit question and the methodology to measure the individual patient choice, or preference, as opposed to the collective, or population, choice. We focus specifically on the American Society of Clinical Oncology (ASCO) Value Framework. We argue that its laudable intent to assist in shared clinician-patient decision making can be augmented by more formally adopting methodology underpinned by micro- and health economic concepts, as well as application of formal quantitative approaches. Our recommendations for value frameworks focusing on the individual patient, such as the ASCO Value Framework, are 3-fold: (1) ensure that stakeholders understand the importance of the adopted (economic) perspective; (2) consider using exclusively absolute measures of risk and formal patient-preference methodology; and (3) consider foregoing safety parameters for higher-order utility considerations. DISCLOSURES: No funding was received for conceptualizing, writing, and/or editing this manuscript. Waldeck and White are employees of, and received stock option grants from, Celldex Therapeutics. Van Hout and Botteman are employees and shareholders of Pharmerit International. Pharmerit International is a research contractor for Celldex. All authors have retained editorial control of the content of the manuscript. Conceptualization of this viewpoint article was contributed primarily by Waldeck, along with Botteman, White, and van Hout. Data analysis and revision of the manuscript was contributed equally by all the authors. The manuscript was written by Waldeck, Botteman, van Hout, and White.

Modelling the cost-effectiveness of combination therapy for early, rapidly progressing rheumatoid arthritis by simulating the reversible and irreversible effects of the disease.

OBJECTIVE: To estimate the cost-effectiveness of adalimumab plus methotrexate (MTX) versus MTX monotherapy in early, aggressive rheumatoid arthritis (RA) when explicitly modelling short-term (reversible) and long-term (irreversible, ie, joint damage) disease activity and physical function. METHODS: A microsimulation model was developed to unify, in a single cost-effectiveness model, measures of reversible and irreversible disease activity and physical function based on data from the PREMIER trial. Short term, reversible disease activity was modelled using DAS28 variables, including swollen joint counts, tender joint counts, C reactive protein concentration and pain. The DAS28 variables were then used in a logistic regression to predict short-term American College of Rheumatology (ACR) responses, which informed treatment continuation and switches. Long term, irreversible, radiographically documented joint damage was modelled using modified Total Sharp Score (mTSS). The model then linked both short-term disease activity and mTSS to the Health Assessment Questionnaire score, which was used to calculate direct and indirect costs, and quality adjusted life-years (QALYs). RESULTS: When both reversible and irreversible effects of therapy were included, combination therapy was estimated to produce 6-month 50% ACR responses in 75% of patients versus 54% in MTX monotherapy. Compared to MTX monotherapy, combination therapy resulted in 2.68 and 3.04 discounted life years and QALYs gained, respectively. Combination therapy also resulted in a net increase in direct costs of £106,207 for a resulting incremental cost/QALY gain of £32,425. When indirect costs were included in the analysis, the ICER (incremental cost-effectiveness ratio) decreased to £27,238. Disregarding irreversible effects increased the incremental cost-effectiveness ratio to £78,809 (when only direct costs were included). CONCLUSIONS: Starting with adalimumab plus MTX combination therapy in early, aggressive RA is cost-effective when irreversible damage is adequately considered.

Cost-effectiveness Analysis of Rivaroxaban in the Secondary Prevention of Acute Coronary Syndromes in Sweden.

BACKGROUND: Worldwide, coronary heart disease accounts for 7 million deaths each year. In Sweden, acute coronary syndrome (ACS) is a leading cause of hospitalization and is responsible for 1 in 4 deaths. OBJECTIVE: The aim of this analysis was to assess the cost-effectiveness of rivaroxaban 2.5 mg twice daily (BID) in combination with standard antiplatelet therapy (ST-APT) versus ST-APT alone, for the secondary prevention of ACS in adult patients with elevated cardiac biomarkers without a prior history of stroke/transient ischemic attack (TIA), from a Swedish societal perspective, based on clinical data from the global ATLAS ACS 2-TIMI 51 trial, literature-based quality of life data and costs sourced from Swedish national databases. METHODS: A Markov model was developed to capture rates of single and multiple myocardial infarction (MI), ischemic and hemorrhagic stroke, thrombolysis in myocardial infarction (TIMI) major, minor, and "requiring medical attention" bleeds, revascularization events, and associated costs and utilities in patients who were stabilized after an initial ACS event. Efficacy and safety data for the first 2 years came from the ATLAS ACS 2-TIMI 51 trial. Long-term probabilities were extrapolated using safety and effectiveness of acetylsalicylic acid data, which was estimated from published literature, assuming constant rates in time. Future cost and effects were discounted at 3.0%. Univariate and probabilistic sensitivity analyses were conducted. RESULTS: In the base case, the use of rivaroxaban 2.5 mg BID was associated with improvements in survival and quality-adjusted life years (QALYs), yielding an incremental cost per QALY of 71,246 Swedish Krona (SEK) (€8045). The outcomes were robust to changes in inputs. The probabilistic sensitivity analysis demonstrated rivaroxaban 2.5 mg BID to be cost-effective in >99.9% of cases, assuming a willingness-to-pay threshold of SEK 500,000 (€56,458). CONCLUSION: Compared with ST-APT alone, the use of rivaroxaban 2.5 mg BID in combination with ST-APT can be considered a cost-effective treatment option for ACS patients with elevated cardiac biomarkers without a prior history of stroke/TIA in Sweden. FUNDING: Bayer Pharma AG.

Assessing uncertainties surrounding combined endpoints for use in economic models.

BACKGROUND: To increase power to detect a treatment effect, trials may combine multiple endpoints such as survival, myocardial infarctions, and strokes. When such trials are used to define the uncertainty associated with input parameters in an economic model, the output uncertainty will depend on the way in which the dependency between individual endpoints is modeled. OBJECTIVE: To develop a flexible approach to model the interrelationship between individual components of a combined endpoint. METHODS: A standard independent Dirichlet approach is compared with a dependent Dirichlet approach and logistic approaches. The logistic approaches use a link between the various endpoints by either an observed clinical variable (cholesterol) or a latent one. The logistic and Dirichlet methods are compared using 6 statin trials including 5 endpoints: myocardial infarction (MI), stroke, fatal MI, fatal stroke, and other cardiovascular death. The results are compared using the point estimates and uncertainty in a simplified cardiovascular model to calculate point estimates and uncertainty of estimated incremental life-years when applying probabilistic sensitivity analysis. The influence of the link between endpoints is tested by changing the prior in the logistic approaches. RESULTS: The dependent Dirichlet approach reduces uncertainty up to 29% and changes the point estimate by up to 28%. The logistic approach with uninformative priors does not affect the uncertainty and point estimates. When strong priors are used, the uncertainty margins get smaller (up to 49%) and point estimates vary more. Including information about cholesterol has limited impact. CONCLUSIONS: The logistic approaches offer a flexible way to reflect one's beliefs about the interrelationships between individual endpoints, potentially decreasing uncertainty margins. The approach works equally well with and without data concerning the underlying disease process.

Cost-effectiveness of additional blood screening tests in the Netherlands.

BACKGROUND: During the past decade, blood screening tests such as triplex nucleic acid amplification testing (NAT) and human T-cell lymphotropic virus type I or I (HTLV-I/II) antibody testing were added to existing serologic testing for hepatitis B virus (HBV), human immunodeficiency virus (HIV), and hepatitis C virus (HCV). In some low-prevalence regions these additional tests yielded disputable benefits that can be valuated by cost-effectiveness analyses (CEAs). CEAs are used to support decision making on implementation of medical technology. We present CEAs of selected additional screening tests that are not uniformly implemented in the EU. STUDY DESIGN AND METHODS: Cost-effectiveness was analyzed of: 1) HBV, HCV, and HIV triplex NAT in addition to serologic testing; 2) HTLV-I/II antibody test for all donors, for first-time donors only, and for pediatric recipients only; and 3) hepatitis A virus (HAV) for all donations. Disease progression of the studied viral infections was described in five Markov models. RESULTS: In the Netherlands, the incremental cost-effectiveness ratio (ICER) of triplex NAT is €5.20 million per quality-adjusted life-year (QALY) for testing minipools of six donation samples and €4.65 million/QALY for individual donation testing. The ICER for anti-HTLV-I/II is €45.2 million/QALY if testing all donations, €2.23 million/QALY if testing new donors only, and €27.0 million/QALY if testing blood products for pediatric patients only. The ICER of HAV NAT is €18.6 million/QALY. CONCLUSION: The resulting ICERs are very high, especially when compared to other health care interventions. Nevertheless, these screening tests are implemented in the Netherlands and elsewhere. Policy makers should reflect more explicit on the acceptability of costs and effects whenever additional blood screening tests are implemented.

Cross-sectional study into the costs and impact on family functioning of 4-year-old children with aggressive behavior.

Early-onset aggressive behavior is known for its negative developmental consequences, and the associated high costs for families, the health care system and wider society. Although the origins of aggressive behavior are to be found in early childhood, the costs incurred by aggressive behavior of young children have not been studied extensively. The present study aimed to investigate whether preschool children with a high level of aggressive behavior already differ in the generated amount of costs and impact on family functioning from children with lower levels of aggressive behavior. A population-based sample of 317 preschool children was divided into four groups with different levels of aggression (moderate, borderline, clinical). Parents filled out questionnaires to assess service use (lifetime and past 3 months) and impact on family functioning. Over the past 3 months as well as over the first 4 years of life, children with a clinical level of aggression were more costly than children with a low level of aggression (mean total costs over the past 3 months: low € = 167,05 versus clinical € = 1034,83 and mean lifetime costs: low € = 817,37 versus clinical € = 1433,04), due to higher costs of services used by the child. In addition, families of children with a borderline or clinical level of aggressive behavior reported more impairment in their daily functioning than families of children with lower levels of aggression. The findings demonstrate that a high level of aggressive behavior results in high costs and impaired family functioning in the preschool years already.

A modeling approach to evaluate long-term outcome of prophylactic and on demand treatment strategies for severe hemophilia A.

BACKGROUND: Severe hemophilia requires life-long treatment with expensive clotting factor concentrates; studies comparing effects of different therapeutic strategies over decades are very difficult to perform. A simulation model was developed to evaluate the long-term outcome of on demand, prophylactic and mixed treatment strategies for patients with severe hemophilia A. DESIGN AND METHODS: A computer model was developed based on individual patients' data from a Dutch cohort study in which intermediate dose prophylaxis was used and a French cohort study in which on demand treatment was used, and multivariate regression analyses. This model simulated individual patients' life expectancy, onset of bleeding, life-time joint bleeds, radiological outcome and concentrate use according to the different treatment strategies. RESULTS: According to the model, life-time on demand treatment would result in an average of 1,494 joint bleeds during the hemophiliac's life, and consumption of 4.9 million IU of factor VIII concentrate. In contrast, life-time intermediate dose prophylaxis resulted in a mean of 357 joint bleeds and factor consumption of 8.3 million IU. A multiple switch strategy (between prophylactic and on demand treatment based on bleeding pattern) resulted in a mean number of 395 joint bleeds and factor consumption of 6.6 million IU. The estimated proportion of patients with Pettersson scores over 28 points was 32% for both the prophylactic and the multiple switching strategies, compared to 76% for continuous on demand treatment. CONCLUSIONS: The present model allows evaluation of the impact of various treatment strategies on patients' joint bleeds and clotting factor consumption. It may be expanded with additional data to allow more precise estimates and include economic evaluations of treatment strategies.

Quantifying cost-effectiveness of controlling nosocomial spread of antibiotic-resistant bacteria: the case of MRSA.

BACKGROUND: The costs and benefits of controlling nosocomial spread of antibiotic-resistant bacteria are unknown. METHODS: We developed a mathematical algorithm to determine cost-effectiveness of infection control programs and explored the dynamical interactions between different epidemiological variables and cost-effectiveness. The algorithm includes occurrence of nosocomial infections, attributable mortality, costs and efficacy of infection control and how antibiotic-resistant bacteria affect total number of infections: do infections with antibiotic-resistant bacteria replace infections caused by susceptible bacteria (replacement scenario) or occur in addition to them (addition scenario). Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia was used for illustration using observational data on S. aureus bacteremia (SAB) in our hospital (n = 189 between 2001-2004, all being methicillin-susceptible S. aureus [MSSA]). RESULTS: In the replacement scenario, the costs per life year gained range from 45,912 euros to 6590 euros for attributable mortality rates ranging from 10% to 50%. Using 20,000 euros per life year gained as a threshold, completely preventing MRSA would be cost-effective in the replacement scenario if attributable mortality of MRSA is > or = 21%. In the addition scenario, infection control would be cost saving along the entire range of estimates for attributable mortality. CONCLUSIONS: Cost-effectiveness of controlling antibiotic-resistant bacteria is highly sensitive to the interaction between infections caused by resistant and susceptible bacteria (addition or replacement) and attributable mortality. In our setting, controlling MRSA would be cost saving for the addition scenario but would not be cost-effective in the replacement scenario if attributable mortality would be < 21%.

Costs and consequences of clopidogrel versus aspirin for secondary prevention of ischaemic events in (high-risk) atherosclerotic patients in Sweden: a lifetime model based on the CAPRIE trial and high-risk CAPRIE subpopulations.

BACKGROUND: Antiplatelet therapy plays a central role in the prevention of atherothrombotic events. Both acetylsalicylic acid (aspirin) and clopidogrel have been shown to reduce the risk of recurrent cardiovascular events in various subgroups of patients with vascular disease. OBJECTIVE: To estimate the cost effectiveness of clopidogrel versus aspirin in Sweden for the prevention of atherothrombotic events based on CAPRIE trial data. The focus of this study is on two high-risk subpopulations: (i) patients with pre-existing symptomatic atherosclerotic disease; and (ii) patients with polyvascular disease. METHODS: A Markov model combining clinical, epidemiological and cost data was used to assess the economic value of clopidogrel compared with aspirin during a patient's lifetime. A societal perspective was used, with costs stated in Swedish kronor (SEK), year 2007 values. For the first 2 years, the clinical input for the model was based on the relevant subpopulations in the CAPRIE trial. Thereafter, transition probabilities were extrapolated, taking account of increased risks related to age and to a history of events. Cost effectiveness of 2 years of therapy is presented as cost per life-year gained (LYG) and as cost per QALY. Univariate and multivariate sensitivity analyses were performed to investigate robustness of results. RESULTS: For patients resembling the total CAPRIE population, who were treated with clopidogrel, the expected cost per LYG was SEK217,806 and the cost per QALY was estimated at SEK169,154. For the high-risk CAPRIE subpopulations, costs per QALY were lowest for patients with pre-existing symptomatic atherosclerotic disease (SEK38,153). Using a 'willingness-to-pay' perspective indicated that treatment with clopidogrel instead of aspirin in high-risk patients is associated with a high probability for cost effectiveness; 81% using a threshold of SEK100,000 per QALY and 98% using a threshold of SEK500,000 per QALY. Overall, the results appeared to be robust over the sensitivity analyses performed. CONCLUSION: When considering the cost-effectiveness categorization as proposed by the Swedish National Board of Health and Welfare, clopidogrel appears to be associated with costs per QALY that range from intermediate in the total CAPRIE population to low in high-risk atherosclerotic patients.

Comparative effectiveness of antibiotics for the treatment of MRSA complicated skin and soft tissue infections.

OBJECTIVE: With a growing number of studies and comparators in MRSA skin infections, a unified framework for comparing treatments is needed for health technology assessment (HTA). The objective was to systematically assess the success rates of common antimicrobial agents for the treatment of complicated skin and soft tissue infections (cSSTIs) caused by MRSA. METHODS: MEDLINE, EMBASE, and Cochrane databases were searched to identify published clinical trials in which dalbavancin, daptomycin, linezolid, telavancin, teicoplanin, tigecycline, and vancomycin were used to treat cSSTIs. Pooled efficacy estimates were generated from clinical and microbiological determinations of success for the MRSA-subgroups in cSSTI clinical trials using a Bayesian meta-analytic approach. Success rates for each antibiotic were reported with 95% Bayesian confidence intervals (called credible intervals [CrI]). In sensitivity analyses the impact of different model parameters and article quality were investigated. RESULTS: Out of 36 identified studies, 14 studies on six antibiotics with 28 treatment arms (n = 1840) were included in the analysis. No MRSA data in cSSTI were found for teicoplanin. The pooled success rate and CrI(95%) for each agent was: vancomycin (74.7%; CrI(95%): 64.1%-83.5%), dalbavancin (87.7%; CrI(95%): 74.6%-95.4%), linezolid (84.4%; CrI(95%): 76.6%-90.6%), telavancin (83.5%; CrI(95%): 73.6%-90.8%), daptomycin (78.1%; CrI(95%): 54.6%-93.2%) and tigecycline (70.4%; CrI(95%): 48.0%-87.6%). Comparisons between antibiotics suggested differences versus vancomycin for linezolid (+9.7%; CrI(95%): 4.4%-15.8%), dalbavancin (+13.1%; CrI(95%): 1.0%-23.8%), and telavancin (+8.8%; CrI(95%): 1.5-16.7%). The finding of lower vancomycin efficacy in MRSA cSSTI did not change in sensitivity analyses. CONCLUSION: The results of this meta-analysis suggest higher success rates for linezolid and the new glycopeptides (dalbavancin and telavancin) in MRSA-confirmed cSSTIs. The uncertainty margins reflect the study limitations including number of cases and indirect nature of the comparisons. This example of Bayesian meta-analysis for MRSA cSSTI provides a potential framework for comparisons that is useful for HTA and formulary decision-making.

Modelling approaches: the case of schizophrenia.

Schizophrenia is a chronic disease characterized by periods of relative stability interrupted by acute episodes (or relapses). The course of the disease may vary considerably between patients. Patient histories show considerable inter- and even intra-individual variability. We provide a critical assessment of the advantages and disadvantages of three modelling techniques that have been used in schizophrenia: decision trees, (cohort and micro-simulation) Markov models and discrete event simulation models. These modelling techniques are compared in terms of building time, data requirements, medico-scientific experience, simulation time, clinical representation, and their ability to deal with patient heterogeneity, the timing of events, prior events, patient interaction, interaction between co-variates and variability (first-order uncertainty). We note that, depending on the research question, the optimal modelling approach should be selected based on the expected differences between the comparators, the number of co-variates, the number of patient subgroups, the interactions between co-variates, and simulation time. Finally, it is argued that in case micro-simulation is required for the cost-effectiveness analysis of schizophrenia treatments, a discrete event simulation model is best suited to accurately capture all of the relevant interdependencies in this chronic, highly heterogeneous disease with limited long-term follow-up data.

A probabilistic model for analyzing viral risks of plasma-derived medicinal products.

BACKGROUND: The prevention of transmission of viral infections by plasma-derived medicinal products is of concern to manufacturers, legislators, and patient representative groups. Recent European legislation requires a viral risk assessment for all new marketing applications of such products. STUDY DESIGN AND METHODS: A discrete event Monte Carlo model was developed to determine the viral transmission risks of the plasma-derived medicinal products. The model incorporates donor epidemiology, donation intervals, efficiency of screening tests for viral markers, inventory hold period, size and composition of the manufacturing pool, production time, process virus reduction capacity, and product yield. With the model, the human immunodeficiency virus (HIV) and hepatitis C virus (HCV) contamination risks of a typical hypothetical plasma product were calculated, and the sensitivity of the risk to various model variables was analyzed. RESULTS: The residual HIV and HCV risks of the finished products are linear in change with viral incidence rate and inversely linear with product yield and process virus reduction capacity. For the product analyzed in this article, the residual risk is less sensitive to changes in screening test pool size, donation frequency, and inventory hold period. There is only a limited dependency on the donation type (apheresis or whole-blood donations) and a negligible dependency on the manufacturing pool size. CONCLUSIONS: The use of probabilistic model simulation techniques is indispensable when estimating realistic residual viral risks of plasma-derived medicinal products. In contrast to conventional deterministic residual risk estimations, the probabilistic approach allows incorporation of specific manufacturing decisions and therefore provides the only feasible alternative for a correct assessment of residual risks.

Long-term clopidogrel therapy in patients receiving percutaneous coronary intervention.

BACKGROUND: The PCI-CURE (Percutaneous Coronary Intervention-Clopidogrel in Unstable Angina to Prevent Recurrent Events) and CREDO (Clopidogrel for the Reduction of Events During Observation) studies have demonstrated that, in addition to aspirin, pre-treatment with clopidogrel followed by long-term (i.e. 9-12 months) therapy significantly reduces the risk of atherothrombotic events in patients undergoing percutaneous coronary intervention (PCI). OBJECTIVE: To examine the economic implications, from the Dutch healthcare perspective, of the use of clopidogrel in patients undergoing PCI (elective procedures or in patients with acute coronary syndrome), comparing pre-treatment followed by long-term therapy with only 4 weeks of treatment. METHODS: A lifetime Markov model was used to combine data from the PCI-CURE and CREDO trials with data from the literature concerning epidemiology, costs and quality of life. The model was run separately for each trial. Only direct healthcare costs (euro, year 2004 values) were considered. Costs and outcomes were discounted at 4% per anum. For each trial, the cost effectiveness is expressed as costs per life-year and QALY gained. Uncertainties are addressed by uni- and probabilistic multivariate sensitivity analysis. RESULTS: When starting with the data from the PCI-CURE trial, pre-treatment plus 9-month clopidogrel therapy was predicted to save 1119 euros and gain 0.03 life-years and 0.07 QALYs per patient compared with short-term treatment. When starting with the data from the CREDO trial, the combination of pre-treatment and prolonged clopidogrel therapy (1 year) was estimated to save 497 euros and gain 0.10 life-years and 0.14 QALYs per patient. Univariate and probabilistic multivariate sensitivity analyses suggested that the conclusions were generally robust, but that the expected gain in survival for the PCI-CURE population was very sensitive to the effects on mortality within the combined endpoint of myocardial infarction/stroke-free survival. CONCLUSIONS: In The Netherlands, pre-treatment plus long-term (9-12 months) therapy with clopidogrel is estimated to save costs and increase (quality-adjusted) survival in the prevention of ischaemic events among patients undergoing elective PCI (CREDO) and in patients with acute coronary syndrome (PCI-CURE) compared with short-term treatment with clopidogrel without pre-treatment.

Cost-effectiveness of the unrestricted use of sirolimus-eluting stents vs. bare metal stents at 1 and 2-year follow-up: results from the RESEARCH Registry.

AIMS: To assess the cost-effectiveness of sirolimus-eluting stents (SESs) compared with bare metal stents (BMSs) as the default strategy in unselected patients treated in the Rapamycin Eluting Stent Evaluated At Rotterdam Cardiology Hospital (RESEARCH) Registry at 1 and 2-years following the procedure. METHODS AND RESULTS: A total of 508 consecutive patients with de novo lesions exclusively treated with SES were compared with 450 patients treated with BMS from the immediate preceding period. Resource use and costs of the index procedure, and clinical outcomes were prospectively recorded over a 2-year follow-up period. Follow-up costs were measured as unit costs per patient based on the incidence of clinically driven target vessel revascularization (TVR), to obtain cumulative costs at 1 and 2-years. Cost-effectiveness was measured as the incremental cost-effectiveness ratio (ICER) per TVR avoided. The use of SES cost euro 3,036 more per patient at the index procedure, driven by the price of SES. Follow-up costs after 1-year were euro 1,089 less with SES when compared with BMS, due to less TVR, resulting in a net excess cost of euro 1,968 per patient in the SES group, and reduced by a further euro 100 per patient in the second year. The incidence of death or myocardial infarction between groups was similar at 1 and 2 years. Rates of TVR in the SES and BMS groups were 3.7% vs. 10.4%, P<0.01 at 1 year, respectively; and 6.4% vs. 14.7%, P<0.001 at 2 years. The ICER per TVR avoided was euro 29,373 at 1 year, and euro 22,267 at 2 years. CONCLUSION: The use of SES, while significantly beneficial in reducing the need for repeat revascularization, was more expensive and not cost-effective in the RESEARCH registry at either 1 or 2-years when compared with BMS. On the basis of these results, in an unselected population with 1 year of follow-up, the unit price of SES would have to be euro 1,023 in order to be cost-neutral.

Costs and benefits of bacterial culturing and pathogen reduction in the Netherlands.

BACKGROUND: Bacterial contamination is a life-threatening risk of blood transfusion, especially with platelet (PLT) transfusions. Bacterial culturing (BCU) of PLTs as well as pathogen reduction (PRT) reduce the likelihood of such contamination. The cost-effectiveness (CE) of these interventions was analyzed after the introduction of the diversion pouch during blood collection. STUDY DESIGN AND METHODS: The balance between costs and benefits of preventing adverse events due to PLT transfusion was assessed with a mathematical decision model and Monte Carlo simulations. Model parameters were obtained from the literature and from Dutch Sanquin blood banks. The balance between costs and benefits is assessed in terms of costs per quality-adjusted life-year (QALY). RESULTS: The costs per 100,000 PLT concentrates in the Netherlands are estimated at $3,277,032 (euro2,520,794) for BCU and at $18,582,844 (euro14,294,495) for PRT. In comparison to the situation without BCU and PRT, costs per QALY are estimated at $90,697 (euro69,767) for BCU (95% confidence interval [CI], $18,149-$2,088,854) and at $496,674 (euro382,057) for PRT (95% CI, $143,950-$8,171,133). The ratio of differences in costs and QALYs between BCU and PRT (the relative CE) is estimated at $3,596,256 (euro2,766,351; 95% CI, $1,100,630-$24,756,615). Large uncertainty in sepsis complication rates and PLT recipient survival exist, causing large uncertainties in the absolute CE for both interventions. CONCLUSIONS: As a result of the unknown probability of sepsis complications and PLT recipient survival, the CE ratios of BCU and PRT in the Dutch setting are highly uncertain. Despite these large uncertainties, it can be concluded that BCU is without doubt more cost-effective than PRT.