Cost-effectiveness of enzyme replacement therapy with alglucosidase alfa in classic-infantile patients with Pompe disease

Therapeutics in paediatric genetic diseases: Current and future landscape

There are more than 7,000 paediatric genetic diseases (PGDs) but less than 5% have treatment options. Treatment strategies targeting different levels of the biological process of the disease have led to optimal health outcomes in a subset of patients with PGDs, where treatment is available. In the past 3 decades, there has been rapid advancement in the development of novel therapies, including gene therapy, for many PGDs. The therapeutic success of treatment relies heavily on knowledge of the genetic basis and the disease mechanism. Specifically, gene therapy has been shown to be effective in various clinical trials, and indeed, these trials have led to regulatory approvals, paving the way for gene therapies for other types of PGDs. In this review, we provide an overview of the treatment strategies and focus on some of the recent advancements in therapeutics for PGDs.

A systematic review of economic evaluations of enzyme replacement therapy in Lysosomal storage diseases

Objective

The objective of this paper is to assess the economic profile of enzyme replacement therapy (ERT) to symptomatic patients with Pompe, Fabry, Gaucher disease and Lysosomal acid lipase (LAL) deficiency.

Methods

A systematic search was performed to retrieve and critically assess economic evaluations of enzyme replacement therapy. Publications were screened according to predefined criteria and evaluated according to the Quality of Economic Studies. Data were narratively synthesized.

Results

The Incremental Cost-Effectiveness Ratio greatly exceeded willingness to pay thresholds. The cost of the medication dominated the sensitivity analysis. For Infantile-onset Pompe’s disease, the incremental cost-effectiveness ratio (ICER) was estimated at €1.043.868 per Quality-adjusted life year (QALY) based on the dose of alglucosidase 40 mg/kg/ week, and €286.114 per QALY for 20 mg of alglucosidase/kg/2 weeks. For adults patients presenting with Pompe disease the reported was ICER € 1.8 million/ QALY. In the case of Fabry disease, the ICER per QALY amounts to 6.1 million Euros/QALY. Respectively for Gaucher’s disease, the ICER /QALY was estimated at € 884,994 per QALY. Finally, for patients presenting LAL deficiency NCPE perpetuated an ICER of €2,701,000/QALY.

Discussion

ERT comprise a promising treatment modality for orphan diseases; nevertheless, it is interlaced with a substantial economic burden. Moreover, the available data on the cost-effectiveness ratio are scarce. For certain diseases, such as Fabry, a thorough selection of patients could exert a beneficial effect on the reported ICER. Steep price reductions are imperative for these products, in the conventional reimbursement pathway or a new assessment framework should be elaborated, which in principle, should target uncertainty.

Health and economic outcomes of newborn screening for infantile-onset Pompe disease

PURPOSE

To estimate health and economic outcomes associated with newborn screening (NBS) for infantile-onset Pompe disease in the United States.

METHODS

A decision analytic microsimulation model simulated health and economic outcomes of a birth cohort of 4 million children in the United States. Universal NBS and treatment was compared with clinical identification and treatment of infantile-onset Pompe disease. Main outcomes were projected cases identified, costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) over the life course.

RESULTS

Universal NBS for Pompe disease and confirmatory testing was estimated to cost an additional $26 million annually. Additional medication costs associated with earlier treatment initiation were $181 million; however, $8 million in medical care costs for other services were averted due to delayed disease progression. Infants with screened and treated infantile-onset Pompe disease experienced an average lifetime increase of 11.66 QALYs compared with clinical detection. The ICER was $379,000/QALY from a societal perspective and $408,000/QALY from the health-care perspective. Results were sensitive to the cost of enzyme replacement therapy.

CONCLUSION

Newborn screening for Pompe disease results in substantial health gains for individuals with infantile-onset Pompe disease, but with additional costs.

Can the Consideration of Societal Costs Change the Recommendation of Economic Evaluations in the Field of Rare Diseases? An Empirical Analysis

OBJECTIVES

To analyze whether the adoption of a societal perspective would alter the results and conclusions of economic evaluations for rare disease-related healthcare technologies.

METHODS

A search strategy involving all the active substances considered as orphan drugs by the European Medicines Agency plus a list of 76 rare diseases combined with economic-related terms was conducted on Medline and the Cost-Effectiveness Registry from the beginning of 2000 until November 2018. We included studies that considered quality-adjusted life years as an outcome, were published in a scientific journal, were written in English, included informal care costs or productivity losses, and separated the results according to the applied perspective.

RESULTS

We found 14 articles that fulfilled the inclusion criteria. Productivity losses were considered in 12 studies, the human capital approach being the method most frequently used. Exclusively, informal care was considered in 2 articles, being valued through the opportunity cost method. The 14 articles selected resulted in 26 economic evaluation estimations, from which incremental cost-utility ratio values changed from cost-effective to dominant in 3 estimates, but the consideration of societal costs only modified the authors' conclusion in 1 study.

CONCLUSIONS

The presence of societal costs in the economic evaluation of rare diseases did not affect the conclusions of the studies except in a single specific case. In those studies where the societal perspective was considered, we did not find significant changes in the economic evaluation results due to the higher costs of treatments and the low quality-adjusted life-years gained.

Cost-effectiveness analysis of enzyme replacement therapy (ERT) for treatment of infantile-onset Pompe disease (IOPD) in the Iranian pharmaceutical market

Infantile-onset Pompe disease (IOPD) or acid maltase deficiency is a rare metabolic disorder. It is caused by a deficiency in functioning of the enzyme acid alpha-glucosidase and leads to the accumulation of glycogen in the liver, heart, muscle, and other tissues. Myozyme is an effective drug, but it imposes a heavy financial burden on societies and healthcare systems. Therefore, this study was conducted to analyze the cost-effectiveness of Myozyme compared to conventional therapy for the treatment of IOPD. PubMed, Scopus, Web of Science, and Cochrane library databases were searched on December 2018 to identify the effectiveness of Myozyme versus conventional therapy. Then, a cost-effectiveness and a cost utility study were conducted in patients suffering from IOPD. In this cost effectiveness and cost utility analysis, Markov and decision tree models were used for modeling. Model parameters were obtained from international data, and the perspective of the payer was considered. Every cycle was one year; the model was run for 22 cycles. TreeAge pro 2011 was used for analysis. Finally, one-way and probabilistic sensitivity analyses were performed. Two papers were included and 39 patients were evaluated as the treatment group in both studies. Results revealed the effectiveness of Myozyme. Results also revealed a wide range of adverse reactions. Enzyme replacement therapy (ERT) resulted in 4.21038 quality-adjusted life years (QALY) per $381,852. The incremental cost per QALY was $96,809 and the incremental cost per life years gained (LYG) was 74,429 over a 22-year time horizon. Sensitivity analysis indicated the robustness of the results. Myozyme is effective for IOPD and could increase the life expectancy of patients significantly. However, since the calculated incremental cost per QALY was 17 times higher than the GDP per capita of Iran, Myozyme is not cost effective in Iran.

Feasibility Study for Bedside Production of Recombinant Human Acid α-Glucosidase: Technical and Financial Considerations

OBJECTIVE

The high cost of orphan drugs limits their access by many patients, especially in low- and middle-income countries. Many orphan drugs are off-patent without alternative generic or biosimilar versions available. Production of these drugs at the point-of-care, when feasible, could be a cost-effective alternative.

METHODS

The financial feasibility of this approach was estimated by setting up a small-scale production of recombinant human acid alpha-glucosidase (rhGAA). The commercial version of rhGAA is Myozyme™, and Lumizyme™ in the United States, which is used to treat Pompe disease. The rhGAA was produced in CHO-K1 mammalian cells and purified using multiple purification steps to obtain a protein profile comparable to Myozyme™.

RESULTS

The established small-scale production of rhGAA was used to obtain a realistic cost estimation for the magistral production of this biological drug. The treatment cost of rhGAA using bedside production was estimated at $3,484/gram, which is 71% lower than the commercial price of Myozyme ™.

CONCLUSION

This study shows that bedside production might be a cost-effective approach to increase the access of patients to particular life-saving drugs.

A Systematic Review of the Health Economics of Pompe Disease

BACKGROUND

Pompe disease is a rare, severe neuromuscular disease with high mortality and substantial clinical and humanistic burden. However, the economic burden of Pompe disease and the health economic value of its treatments are not well understood. The objectives of this systematic review were to characterize the health economic evidence on Pompe disease, including healthcare resource use and costs (direct and indirect), health utilities, and the cost-effectiveness of current treatments used to manage patients with Pompe disease.

METHODS

A systematic search of MEDLINE^® and Embase^® was performed to retrieve publications on the health economics of Pompe disease. Publications were screened according to predefined criteria, extracted, and quality assessed using the Newcastle-Ottawa Scale. Data were narratively synthesized.

RESULTS

Eight publications evaluated patients with infantile-onset Pompe disease (IOPD) (two studies), late-onset Pompe disease (LOPD) (four studies), or both (two studies). In IOPD, total cost of supportive therapy (excluding treatment) was €32,871 (equivalent to US$41,667 when adjusted for currency and inflation to 2017 US dollars) over a life expectancy of 0.4 years. In adult LOPD, the average annual cost per patient of supportive therapy was €22,475 (adjusted $28,489). Resource use in LOPD was high, with nursing home admissions accounting for 19% of annual direct medical costs. Health economic evaluations estimating incremental costs per quality-adjusted life year (QALY) gained with enzyme-replacement therapy (ERT) versus supportive therapy ranged from £109,991 (adjusted, $186,851) per QALY gained in Columbia to €1,043,868 (adjusted, $1,323,207) in the Netherlands.

DISCUSSION

Despite a full systematic literature search, only eight relevant publications were identified, most of which were of relatively poor quality. However, a significant economic burden of Pompe disease on patients, families, healthcare systems, and society was found, with the majority of costs driven by the only currently approved treatment, ERT. Health economic evaluations of ERT versus supportive therapy vary significantly, with the majority well above willingness-to-pay thresholds. New therapies and approaches to care are needed to address the persistent and lifelong economic burden of Pompe disease and the large incremental cost-effectiveness ratios observed.

Health utilities and parental quality of life effects for three rare conditions tested in newborns

BACKGROUND

Measurement of health utilities is required for economic evaluations. Few studies have evaluated health utilities for rare conditions; even fewer have incorporated disutility that may be experienced by caregivers. This study aimed to (1) estimate health utilities for three rare conditions currently recommended for newborn screening at the state or federal level, and (2) estimate the disutility, or spillover, experienced by parents of patients diagnosed with a rare, heritable disorder.

METHODS

A stated-preference survey using a time trade-off approach elicited health utilities for Krabbe disease, phenylketonuria, and Pompe disease at varying stages (mild, moderate, severe) and onset of disease symptoms (infancy, childhood, and adulthood). We recruited respondents from a nationally representative community sample (n = 862). Respondents valued disease specific health states in three consecutive question frames: (1) adult health state (> = 18 years of age), (2) child health state (< 18 years of age), and (3) as a parent of a child with a condition (parent spillover state). Corresponding mean utilities were calculated for plausible disease states in adulthood and childhood. Mean disutility was estimated for parental spillover. Predictors of utilities were evaluated using a negative binomial regression model.

RESULTS

More severe conditions and infant health states received lower estimated utility and greater estimated disutility among parents. Conditions with the lowest estimated health utilities were severe infantile Pompe disease (0.40, CI: 0.34-0.46) and infantile Krabbe disease (0.37, CI: 0.32-0.43). Disutility was evident for all conditions evaluated (range: 0.07-0.19).

CONCLUSIONS

Rare childhood conditions are associated with substantial estimated losses in quality of life. Evidence of disutility among parents further warrants the inclusion of spillover effects in cost-effectiveness analyses. Continued research is needed to assess and measure the effects of childhood disease from a family perspective.

Cost-Effectiveness of Ventricular Assist Device Destination Therapy for Advanced Heart Failure in Duchenne Muscular Dystrophy

Destination ventricular assist device therapy (DT-VAD) is well accepted in select adults with medically refractory heart failure (HF) who are not transplant candidates; however, its use in younger patients with progressive diseases is unclear. We sought to evaluate the cost-effectiveness of DT-VAD in Duchenne muscular dystrophy (DMD) patients with advanced HF. We created a Markov-state transition model (5-year horizon) to compare survival, costs, and quality of life (QOL) between medical management and DT-VAD in DMD with advanced HF. Model input parameters were derived from the literature. We used sensitivity analyses to explore uncertainty around model assumptions. DT-VAD had higher costs ($435,602 vs. $125,696), survival (3.13 vs. 0.60 years), and quality-adjusted survival (1.99 vs. 0.26 years) than medical management. The incremental cost-effectiveness ratio (ICER) for DT-VAD was $179,086 per quality-adjusted life year (QALY). In sensitivity analyses that were widely varied to account for uncertainty in model assumptions, the DT-VAD strategy generally remained more costly and effective than medical management. Only when VAD implantation costs were <$113,142 did the DT-VAD strategy fall below the $100,000/QALY willingness-to-pay threshold commonly considered to be "cost-effective." In this exploratory analysis, DT-VAD for patients with DMD and advanced HF exceeded societal expectations for cost-effectiveness but had an ICER similar to the accepted practice of DT-VAD in adult HF patients. While more experience and research in this population is needed, our analysis suggests that DT-VAD for advanced HF in DMD should not be dismissed solely based on cost.

Rescue of Pompe disease in mice by AAV-mediated liver delivery of secretable acid α-glucosidase

Glycogen storage disease type II or Pompe disease is a severe neuromuscular disorder caused by mutations in the lysosomal enzyme, acid α-glucosidase (GAA), which result in pathological accumulation of glycogen throughout the body. Enzyme replacement therapy is available for Pompe disease; however, it has limited efficacy, has high immunogenicity, and fails to correct pathological glycogen accumulation in nervous tissue and skeletal muscle. Using bioinformatics analysis and protein engineering, we developed transgenes encoding GAA that could be expressed and secreted by hepatocytes. Then, we used adeno-associated virus (AAV) vectors optimized for hepatic expression to deliver the GAA transgenes to Gaa knockout (Gaa^-/-) mice, a model of Pompe disease. Therapeutic gene transfer to the liver rescued glycogen accumulation in muscle and the central nervous system, and ameliorated cardiac hypertrophy as well as muscle and respiratory dysfunction in the Gaa^-/- mice; mouse survival was also increased. Secretable GAA showed improved therapeutic efficacy and lower immunogenicity compared to nonengineered GAA. Scale-up to nonhuman primates, and modeling of GAA expression in primary human hepatocytes using hepatotropic AAV vectors, demonstrated the therapeutic potential of AAV vector-mediated liver expression of secretable GAA for treating pathological glycogen accumulation in multiple tissues in Pompe disease.

Induced pluripotent stem cell models of lysosomal storage disorders

Induced pluripotent stem cells (iPSCs) have provided new opportunities to explore the cell biology and pathophysiology of human diseases, and the lysosomal storage disorder research community has been quick to adopt this technology. Patient-derived iPSC models have been generated for a number of lysosomal storage disorders, including Gaucher disease, Pompe disease, Fabry disease, metachromatic leukodystrophy, the neuronal ceroid lipofuscinoses, Niemann-Pick types A and C1, and several of the mucopolysaccharidoses. Here, we review the strategies employed for reprogramming and differentiation, as well as insights into disease etiology gleaned from the currently available models. Examples are provided to illustrate how iPSC-derived models can be employed to develop new therapeutic strategies for these disorders. We also discuss how models of these rare diseases could contribute to an enhanced understanding of more common neurodegenerative disorders such as Parkinson’s disease, and discuss key challenges and opportunities in this area of research.

Summary: This Review discusses how induced pluripotent stem cells (iPSCs) provide new opportunities to explore the biology and pathophysiology of lysosomal storage diseases, and how iPSCs have illuminated the role of lysosomes in more common disorders.

Economic Evaluations of Pharmaceuticals Granted a Marketing Authorisation Without the Results of Randomised Trials: A Systematic Review and Taxonomy

BACKGROUND

Pharmaceuticals are usually granted a marketing authorisation on the basis of randomised controlled trials (RCTs). Occasionally the efficacy of a treatment is assessed without a randomised comparator group (either active or placebo).

OBJECTIVE

To identify and develop a taxonomic account of economic modelling approaches for pharmaceuticals licensed without RCT data.

METHODS

We searched PubMed, the websites of UK health technology assessment bodies and the International Society for Pharmacoeconomics and Outcomes Research Scientific Presentations Database for assessments of treatments granted a marketing authorisation by the US Food and Drug Administration or European Medicines Agency from January 1999 to May 2014 without RCT data (74 indications). The outcome of interest was the approach to modelling efficacy data.

RESULTS

Fifty-one unique models were identified in 29 peer-reviewed articles, 30 health technology appraisals, and 15 International Society for Pharmacoeconomics and Outcomes Research abstracts concerning 30 indications (44 indications had not been modelled). We noted the high rate of non-submission to health technology assessment agencies (28/98). The majority of models (43/51) were based on 'historical controls'-comparisons to previous meta-analysis or pooling of trials (5), individual trials (16), registries/case series (15), or expert opinion (7). Other approaches used the patient as their own control, performed threshold analysis, assumed time on treatment was added to overall survival, or performed cost-minimisation analysis.

CONCLUSIONS

There is considerable variation in the quality and approach of models constructed for drugs granted a marketing authorisation without a RCT. The most common approach is of a naive comparison to historical data (using other trials/registry data as a control group), which has considerable scope for bias.

State of rare disease management in Southeast Asia

Background

Rare diseases, also referred to as orphan diseases, are characterised by their low prevalence with majority of them are chronically debilitating and life threatening. Given the low prevalence and the widely dispersed but very small patient base for each disease, there may often be a disproportion in the availability of treatments and resources to manage patients, spur research and train experts. This is especially true in Southeast Asian countries that are currently in the process of implementing or revising their universal health coverage schemes. This paper aims to examine the status of rare disease management in Southeast Asian countries. It will serve as the basis for a more active discussion on how countries in the region can address an under-recognised rare disease burden and enhance national and regional capacities.

Methods

The study consists of literature reviews and key stakeholders interviews in six focus countries, including the Philippines, Singapore, Malaysia, Indonesia, Vietnam, and Thailand and five countries as best practice, comprising of France, Canada, Australia, Taiwan, and South Korea. Rare disease management initiatives across each country were examined based on the World Health Organization’s framework for action in strengthening health systems.

Results

The results suggest rare disease management remains challenging across Southeast Asia, as many of the focus countries face fundamental issues from basic healthcare systems to funding. Nonetheless, there are substantial improvement opportunities, including leveraging best practices from around the world and organising a multi-stakeholder and regional approach and strategy.

Conclusions

Southeast Asian countries have made significant progress in the management of rare disease, but there remain key areas for substantial development opportunities.

Intracranial arterial abnormalities in patients with late onset Pompe disease (LOPD)

BACKGROUND AND OBJECTIVES

Pompe disease is a rare metabolic disorder due to lysosomal alpha-glucosidase (GAA) deficiency. It is considered as a multi-systemic disease since, although glycogen accumulation is largely prominent in heart, skeletal and respiratory muscles, other organs can also be affected. As regards the vascular system, few reports have documented cerebrovascular malformations in Pompe patients. The aim of this study was to define the presence and type of intracranial arterial abnormalities in a cohort of late onset Pompe disease (LOPD) patients.

METHODS

We have studied 21 LOPD patients with cerebral CT angiography (CTA), using maximum intensity projection and volume rendering technique for 3D-image reconstruction.

RESULTS

We found intracranial arterial abnormalities in 13/21 patients (62 %), of whom: 2/21 patients (9.5 %) showed an unruptured intracranial aneurysm (respectively 2 and 4 mm), 10/21 (47 %) had a vertebrobasilar dolichoectasia (VBD) and 1/21 a basilar artery fenestration. Signs of lacunar encephalopathy (insular, capsular and frontal subcortical lesions) were detected in 13/21 patients (62 %) and this correlated with the presence of respiratory impairment (p = 0.017).

CONCLUSIONS

These findings differ from what has been previously observed in healthy, aged-matched populations and confirm that cerebral arteries abnormalities, mainly involving the posterior circle, are not so rare in LOPD patients and are often accompanied by a lacunar encephalopathy that might represent a hypoxic-ischemic origin. A CTA or an MRA is recommended, in LOPD patients, for early detection of cerebrovascular malformations as they could lead to life-threatening events such as sub-arachnoid haemorrhage or brainstem compression.

Showing Value in Newborn Screening: Challenges in Quantifying the Effectiveness and Cost-Effectiveness of Early Detection of Phenylketonuria and Cystic Fibrosis

Decision makers sometimes request information on the cost savings, cost-effectiveness, or cost-benefit of public health programs. In practice, quantifying the health and economic benefits of population-level screening programs such as newborn screening (NBS) is challenging. It requires that one specify the frequencies of health outcomes and events, such as hospitalizations, for a cohort of children with a given condition under two different scenarios-with or without NBS. Such analyses also assume that everything else, including treatments, is the same between groups. Lack of comparable data for representative screened and unscreened cohorts that are exposed to the same treatments following diagnosis can result in either under- or over-statement of differences. Accordingly, the benefits of early detection may be understated or overstated. This paper illustrates these common problems through a review of past economic evaluations of screening for two historically significant conditions, phenylketonuria and cystic fibrosis. In both examples qualitative judgments about the value of prompt identification and early treatment to an affected child were more influential than specific numerical estimates of lives or costs saved.

Value of predictive bioinformatics in inherited metabolic diseases

Typically, inherited metabolic diseases arise from point mutations in genes encoding metabolic enzymes. Although some of these mutations directly affect amino acid residues in the active sites of these enzymes, the majority do not. It is now well accepted that the majority of these disease-associated mutations exert their effects through alteration of protein stability, which causes a reduction in enzymatic activity. This finding suggests a way to predict the severity of newly discovered mutations. In silico prediction of the effects of amino acid sequence alterations on protein stability often correlates with disease severity. However, no stability prediction tool is perfect and, in general, better results are obtained if the predictions from a variety of tools are combined and then interpreted. In addition to predicted alterations to stability, the degree of conservation of a particular residue can also be a factor which needs to be taken into account: alterations to highly conserved residues are more likely to be associated with severe forms of the disease. The approach has been successfully applied in a variety of inherited metabolic diseases, but further improvements are necessary to enable robust translation into clinically useful tools.

The quality of economic evaluations of ultra-orphan drugs in Europe - a systematic review

An orphan disease is defined in the EU as a disorder affecting less than 1 in 2 000 individuals. The concept of ultra-orphan has been proposed for diseases with a prevalence of less than 1:50 000. Drugs for ultra-orphan diseases are amongst the most expensive medicines on a cost-per-patient basis. The extremely high prices have prompted initiatives to evaluate cost-effectiveness and cost-utility in EU-member states. The objective of this review was to evaluate the quality of cost-effectiveness and cost-utility studies on ultra-orphan drugs. We searched 2 databases and the reference lists of relevant systematic reviews. Studies reporting on full economic evaluations, or at least aiming at such evaluation, were eligible for inclusion. Quality was assessed with the use of the Consensus on Health Economic Criteria (CHEC)-list. Two-hundred-fifty-one studies were identified. Of these, 16 fitted our inclusion criteria. A study on enzyme replacement and substrate reduction therapies for lysosomal storage disorders did not perform a full economic evaluation due to the high drug costs and the lack of a measurable effect on either clinical or health-related quality of life outcomes. Likewise, a cost-effectiveness analysis of laronidase for mucopolysaccharidosis type 1 was considered unfeasible due to lack of clinical effectiveness data, while in the same study a crude model was used to estimate cost-utility of enzyme replacement therapy (ERT) for Fabry disease. Three additional studies, one on ERT for Fabry disease, one on ERT for Gaucher disease and one on eculizumab for paroxysmal nocturnal haemoglobinuria, used an approach that was too simplistic to lead to a realistic estimate of the incremental cost-effectiveness (ICER) or cost-utility ratio (ICUR). In all other studies (N = 11) more sophisticated pharmacoeconomic models were used to estimate cost-effectiveness and cost-utility of the specific drug, mostly ERT or drugs indicated for pulmonary arterial hypertension (PAH). Seven studies used a Markov-state-transition model. Other models used were patient-level simulation models (N = 3) and decision trees (N = 1). Only 4 studies adopted a societal perspective. All but 2 studies discounted costs and effects appropriately. Drugs for metabolic diseases appeared to be significantly less cost-effective than drugs indicated for PAH, with ICERs ranging from €43 532 (Gaucher disease) to €3 282 252 (Fabry disease). Quality of studies using a Markov-state-transition or patient-level simulation model is in general good with 14–19 points on the CHEC-list. We therefore conclude that economic evaluations of ultra-orphan drugs are feasible if pharmacoeconomic modelling is used. Considering the need for modelling of several disease states and the small patient groups, a Markov-state-transition model seems to be most suitable type of model. However, it should be realised that ultra-orphan drugs will usually not meet the conventional criteria for cost-effectiveness. Nevertheless, ultra-orphan drugs are often reimbursed. Further discussion on the use of economic evaluations and their consequences in case of ultra-orphan drugs is therefore warranted.