The effectiveness and cost-effectiveness of enzyme and substrate replacement therapies: a longitudinal cohort study of people with lysosomal storage disorders.

OBJECTIVES: To determine natural history and estimate effectiveness and cost of enzyme replacement therapy (ERT) and substrate replacement therapy (SRT) for patients with Gaucher disease, Fabry disease, mucopolysaccharidosis type I (MPS I), mucopolysaccharidosis type II (MPS II), Pompe disease and Niemann-Pick type C (NPC) disease. DESIGN: Cohort study including prospective and retrospective clinical- and patient-reported data. Age- and gender-adjusted treatment effects were estimated using generalised linear mixed models. Treated patients contributed data before and during treatment. Untreated patients contributed natural history data. SETTING: National Specialised Commissioning Group-designated lysosomal storage disorder (LSD) treatment centres in England. PARTICIPANTS: Consenting adults and children with a diagnosis of Gaucher disease (n = 272), Fabry disease (n = 499), MPS I (n = 126), MPS II (n = 58), NPC (n = 58) or Pompe disease (n = 93) who had attended a treatment centre in England. INTERVENTIONS: ERT and SRT. MAIN OUTCOME MEASURES: Clinical outcomes chosen by clinicians to reflect disease progression for each disorder; patient-reported quality-of-life (QoL) data; cost of treatment and patient-reported service-use data; numbers of hospitalisations, outpatient and general practitioner appointments; medication use; data pertaining to associated family/carer costs and QoL impacts. RESULTS: Seven hundred and eleven adults and children were recruited. In those with Gaucher disease (n = 175) ERT was associated with improved platelet count, haemoglobin, liver function and reduced risk of enlarged liver or spleen. No association was found between ERT and QoL. In patients with Fabry disease (n = 311) increased time on ERT was associated with small decreases in left ventricular mass and improved glomerular filtration rate, but not with changes in risk of stroke/transient ischaemic attacks or the need for a hearing aid. There was a statistically significant association between duration of ERT use and worsening QoL and fatigue scores. We found no statistical difference in estimates of treatment effectiveness between the two preparations, agalsidase beta (Fabrazyme(®), Genzyme) (n = 127) and agalsidase alpha (Replagal(®), Shire HGT) (n = 91), licensed for this condition. In Pompe disease (n = 77) our data provide some evidence of a beneficial effect on muscle strength and mobility as measured by a 6-minute walk test in adult-onset patients; there were insufficient data from infantile-onset Pompe patients to estimate associations between ERT and outcome. Among subjects with MPS I (n = 68), 42 of the 43 patients with MPS I subtype Hurler's disease had undergone a bone marrow transplant. No significant associations were found between ERT and any outcome measure for the MPS I subtype Scheie disease and heparan sulphate patients. An association between duration of ERT and growth in children was the only statistically significant finding among patients with MPS II (n = 39). There were insufficient data for patients with NPC disease to draw any conclusions regarding the effectiveness of SRT. The current annual cost to the NHS of the different ERTs means that between 3.6 and 17.9 discounted quality-adjusted life-years (QALYs) for adult patients and between 2.6 and 10.5 discounted QALYs for child patients would need to be generated for each year of being on treatment for ERTs to be considered cost-effective by conventional criteria. CONCLUSIONS: These data provide further evidence on the effectiveness of ERT in people with LSDs. However, the results need to be interpreted in light of the fact that the data are observational and the relative lack of power due to the small numbers of patients with MPS I, MPS II, Pompe disease and NPC disease. Future work should aim to effectively address the unanswered questions and this will require agreement on a common set of outcome measures and their consistent collection across all treatment centres. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 16, No. 39. See the HTA programme website for further project information.

Stakeholder involvement in expensive drug recommendation decisions: an international perspective.

OBJECTIVES: To describe stakeholder involvement in the priority setting and appeals processes across five drug reimbursement recommendation committees. METHODS: We conducted qualitative case studies of how five independent drug advisory committees from Canada, Israel, England and Wales, Australia, and the USA made funding decisions for six expensive drugs. Interviews with 48 informants were conducted with committee members, patient groups, and industry representatives. RESULTS: Different stakeholders were allowed, in varying degrees, to participate in the formal mechanisms for revisions and appeals of decisions. Participants identified a number of stakeholder groups who were already involved in the process, as well as stakeholders whom they believed should be included in the decision-making process. CONCLUSIONS: A central component of a legitimate and fair priority setting process is to make priority setting explicit and to involve both pertinent values and stakeholders in decision-making. Study participants believed that the involvement of multiple stakeholder groups within the deliberative and appeals/revisions processes would contribute to a fair and legitimate drug reimbursement process.

Modelling the resource implications of managing adults with Fabry disease in Italy.

AIMS: This study estimated the resource implications and budget impact of managing adults with Fabry disease in Italy, from the perspective of the Servizio Sanitario Nazionale (SSN). METHODS: A decision model was constructed using published clinical outcomes and clinician-derived resource utilisation estimates depicting the management of adults with Fabry disease in Italy. RESULTS: The expected annual cost of managing 220 existing and 20 new Fabry patients in Italy was estimated to be €28·3 million. In an average year, patients receiving enzyme replacement therapy (ERT) with 0·2 mg kg(-1) agalsidase alfa (Replagal; Shire Human Genetic Therapies, Basingstoke, Hampshire, UK) or 1·0 mg kg(-1) agalsidase beta (Fabrazyme; Genzyme Europe BV, Naarden, The Netherlands) are collectively expected to make 4500 hospital attendances to a day ward for infusions, which equates to 2000 eight-h days on the day ward associated with ERT. If all ERT-treated patients received their infusions at home, there would be a marginal reduction in the annual health care cost to manage these patients, and the total annual number of days on the day ward associated with ERT in the second year could potentially be reduced from a mean 2000 to zero, thereby releasing substantial hospital resources for use by non-Fabry patients. Currently, only agalsidase alfa is licensed for home treatment in Italy; hence, only patients receiving this enzyme could be offered home treatment. CONCLUSION: Use of agalsidase alfa (0·2 mg kg(-1) ) instead of agalsidase beta (1·0 mg kg(-1)) has the potential to reduce health care costs and release hospital resources in different specialities for alternative use by non-Fabry patients, thereby improving the efficiency of the public health care system in Italy.

Modelling the resource implications of managing adults with Fabry disease in Norway favours home infusion.

BACKGROUND: The aim of this study was to estimate the resource implications and budget impact of managing adults with Fabry disease in Norway, from the perspective of the publicly funded healthcare system. METHODS: A decision model was constructed using published clinical outcomes and clinician-derived resource utilization estimates. The model was used to estimate the annual healthcare cost of managing a cohort of 64 adult Fabry patients in an average year. RESULTS: The expected annual cost of managing 60 existing Fabry patients and four new patients in Norway each year was estimated to be NOK 55·8 million (€6·7 million). In an average year, patients receiving enzyme replacement therapy (ERT) with agalsidase alfa (Replagal(®)) at 0·2 mg kg⁻¹ or agalsidase beta (Fabrazyme(®)) at 1·0 mg kg⁻¹ are collectively expected to make 586 attendances to their family practitioner's office for their infusions, which equates to 128 eight-hour days associated with ERT. Encouraging more patients to undergo home-based infusions has substantial potential to free-up community-based resources. In comparison, the community-related benefit that can be obtained by switching from agalsidase beta (1·0 mg kg⁻¹) to agalsidase alpha (0·2 mg kg⁻¹) is marginal, and dependent on the two doses being clinically equivalent. CONCLUSION: Maximizing the proportion of adults with Fabry disease undergoing home-based infusions has the potential to release community-based resources for alternative use by non-Fabry patients, thereby improving the efficiency of the publicly funded healthcare system in Norway.

Enzyme replacement therapy in orphan and ultra-orphan diseases: the limitations of standard economic metrics as exemplified by Fabry-Anderson disease.

BACKGROUND: Fabry-Anderson disease is an x-linked deficiency of lysosomal alpha-galactosidase A (GALA), resulting in chronic renal failure, cardiac arrhythmia, hypertrophy, valvular disease, pain (acro-paraesthesiae) and stroke, together with premature mortality. The disease has a significant impact on quality of life (QOL), as illustrated by studies using the EQ-5D. A specific treatment is available for Fabry-Anderson disease consisting of intravenous enzyme replacement therapy (ERT) of the deficient enzyme. The variable clinical efficacy and cost of ERT has resulted in reluctance by some health providers to approve it. METHODS: We use the limited QOL data available in the Fabry-Anderson disease literature on ERT to derive standard economic metrics. These were derived by bootstrap estimates of the incremental net benefit (INB) statistics together with a cost-effectiveness acceptability curve relating the willingness to pay to the probability that the INB was >0. The estimates were further developed by adoption of a supplementary Bayesian approach utilising a sceptical and enthusiastic prior of the INB of ERT in Fabry-Anderson disease. RESULTS: ERT for Fabry-Anderson disease is not economically viable by standard health programme evaluation metrics. Based on current ERT costs (year 2005 values), derivation of the INB distribution, and a Bayesian analysis using an enthusiastic and sceptical prior of the INB, an upper (350,000 dollars over 1 year) and lower (175,000 dollars over 1 year) economic cost, respectively, of ERT was derived. CONCLUSION: The cost of ERT will always result in a net deficit to society under current costing and ERT efficacy as determined by the QALY metric. The rules of fair cooperation should govern decision making both for ERT in Fabry-Anderson disease and for funding therapeutic advances in other rare diseases belonging to the orphan and ultra-orphan categories.

[Fabry disease--a diagnostic and therapeutic challenge]. / Fabrys sykdom--en diagnostisk og terapeutisk utfordring.

BACKGROUND: Fabry disease, unlike most other metabolic diseases, is prone to familiar and regional clustering because of X-linked inheritance and normal fertility in affected men. Affected individuals can be offered intravenous enzyme replacement therapy. MATERIALS AND METHODS: In two counties in western Norway there are 41 affected individuals, giving a minimum prevalence of the disease of 1 in 17,000. The patient material is briefly presented. We discuss some of the administrative and financial challenges that this type of diseases present in our public health system. RESULTS AND INTERPRETATION: The great variability in disease expression and severity within and between families delays the diagnosis and necessitates a broad clinical follow up of affected persons. A false diagnosis is often made (e.g. MS, irritable colon, a psychiatric disorder, idiopathic hypertrophic cardiomyopathy, or kidney failure). The follow up regime is briefly described, with special emphasis on the practical and financial implications of enzyme replacement therapy in Norway.

Agalsidase alfa: specific treatment for Fabry disease.

Fabry disease is a rare genetic lysosomal storage disorder characterized by a deficiency of the enzyme alpha-galactosidase A. The recent availability of enzyme-replacement therapy with agalsidase alfa offers specific treatment for this serious, progressive condition.