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

Home-Based Infusion of Alglucosidase Alfa Can Safely be Implemented in Adults with Late-Onset Pompe Disease: Lessons Learned from 18,380 Infusions

BACKGROUND

Enzyme replacement therapy (ERT) with alglucosidase alfa is the treatment for patients with Pompe disease, a hereditary metabolic myopathy. Home-based ERT is unavailable in many countries because of the boxed warning alglucosidase alfa received due to the risk of infusion-associated reactions (IARs). Since 2008, home infusions have been provided in The Netherlands.

OBJECTIVES

This study aimed to provide an overview of our experience with home-based infusions with alglucosidase alfa in adult Pompe patients, focusing on safety, including management of IARs.

METHOD

We analysed infusion data and IARs from adult patients starting ERT between 1999 and 2018. ERT was initially given in the hospital during the first year. Patients were eligible for home treatment if they were without IARs for multiple consecutive infusions and if a trained home nurse, with on-call back-up by a doctor, was available. The healthcare providers graded IARs.

RESULTS

We analysed data on 18,380 infusions with alglucosidase alfa in 121 adult patients; 4961 infusions (27.0%) were given in hospital and 13,419 (73.0%) were given at home. IARs occurred in 144 (2.9%) hospital infusions and 113 (0.8%) home infusions; 115 (79.9% of 144) IARs in hospital and 104 (92.0% of 113) IARs at home were mild, 25 IARs (17.4%) in hospital and 8 IARs (7.1%) at home were moderate, and very few severe IARs occurred (4 IARs in hospital [2.8%] and 1 IAR at home [0.9%]). Only one IAR in the home situation required immediate clinical evaluation in the hospital.

CONCLUSION

Given the small numbers of IARs that occurred with the home infusions, of which only one was severe, we conclude that alglucosidase alfa can be administered safely in the home situation, provided the appropriate infrastructure is present.

Cost-effectiveness of miglustat versus symptomatic therapy of Niemann-Pick disease type C

BACKGROUND

Niemann-Pick disease type C (NP-C) is a progressive neurodegenerative disorder with early infantile (< 2 years), late infantile (2-6 years), juvenile (7-15 years) and adolescent (> 15 years) onset. The mainstay of therapy for NP-C patients with neurological symptoms is miglustat, a drug that may modify the course of the disease.

AIM

Our aim was to evaluate the cost-effectiveness of miglustat in comparison to symptomatic therapy in patients with NP-C in the socio-economic settings of the Republic of Serbia, an upper-middle-income European economy.

METHOD

The perspective of the Serbian Republic Health Insurance Fund was chosen for this study, and the time horizon was eighty years. The main outcomes of the study were quality-adjusted life years gained with miglustat and comparator, and direct costs of treatment. The study was conducted through the generation and simulation of the Discrete-Event Simulation model. The model results were obtained after Monte Carlo microsimulation of a sample with 1000 virtual patients.

RESULTS

Treatment with miglustat was not cost-effective when compared with symptomatic therapy and was associated with negative values of net monetary benefit regardless of the onset of neurological manifestations (- 110,447,627.00 ± 701,614.00 RSD, - 343,871,695.00 ± 2,577,441.00 RSD, - 1,397,908,502.00 ± 23,084,235.00 RSD and - 2,953,680,879.00 ± 33,297,412.00 RSD) for early infantile, late infantile, juvenile and adolescent cohorts, respectively).

CONCLUSION

When traditional pharmacoeconomic evaluation is employed, miglustat is not a cost-effective option in comparison to symptomatic therapy for the treatment of NP-C. However, given the proven efficacy of miglustat, there is a need to find ways to make this drug available to all patients with NP-C.

Current care practices for patients with Duchenne muscular dystrophy in China

BACKGROUND

The coronavirus disease (COVID-19) pandemic has presented challenges in the care of patients with chronic diseases. We identified the challenges faced by Chinese patients with Duchenne muscular dystrophy (DMD) during the pandemic.

METHODS

An online cross-sectional survey was conducted between March 27 and June 30, 2021.

RESULTS

Of the 2105 valid questionnaire responses, 2,056 patients were from non-lockdown areas. In these areas, 42.8% reduced outside daily activities, 49.4% reduced rehabilitation service use, 39.7% postponed regular follow-ups, and 40.8% reported accelerated motor function decline. These figures generally increased for patients from lockdown areas-67.3% reduced outside daily activities, 44.9% reduced rehabilitation service use, 79.6% postponed regular follow-ups, and 55.1% reported accelerated motor function decline. Ambulation loss was most commonly reported in September and March before 2020; however, this trend was absent in 2020. Regarding the informed prices of disease-modifying drugs in Europe and the United States, 86.7% could afford a maximum of one-twentieth of the prices, 8.0% could afford one-tenth of the prices, and only 0.6% of the patients could afford the full prices.

CONCLUSIONS

Implementation of standardized care for DMD in China is consistent with global practices, and the COVID-19 pandemic has affected the care of patients with chronic diseases worldwide, particularly in lockdown areas. Telemedicine is an effective model for providing healthcare to such patients. Healthcare workers should assist patients and establish more robust chronic disease management systems. Collaboration between governmental and non-governmental entities could address the cost of disease-modifying drugs in China and other developing countries.

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.

Promoter considerations in the design of lentiviral vectors for use in treating lysosomal storage diseases

More than 50 lysosomal storage diseases (LSDs) are associated with lysosomal dysfunctions with the frequency of 1:5,000 live births. As a result of missing enzyme activity, the lysosome dysfunction accumulates undegraded or partially degraded molecules, affecting the entire body. Most of them are life-threatening diseases where patients could die within the first or second decade of life. Approximately 20 LSDs have the approved treatments, which do not provide the cure for the disorder. Therefore, the delivery of missing genes through gene therapy is a promising approach for LSDs. Over the years, ex vivo lentiviral-mediated gene therapy for LSDs has been approached using different strategies. Several clinical trials for LSDs are under investigation.Ex vivo lentiviral-mediated gene therapy needs optimization in dose, time of delivery, and promoter-driven expression. Choosing suitable promoters seems to be one of the important factors for the effective expression of the dysfunctional enzyme. This review summarizes the research on therapy for LSDs that has used different lentiviral vectors, emphasizing gene promoters.

Willingness to Pay for Health-Related Quality of Life Gains in Relation to Disease Severity and the Age of Patients

OBJECTIVES

Decision-making frameworks that draw on economic evaluations increasingly use equity weights to facilitate a more equitable and fair allocation of healthcare resources. These weights can be attached to health gains or reflected in the monetary threshold against which the incremental cost-effectiveness ratios of (new) health technologies are evaluated. Currently applied weights are based on different definitions of disease severity and do not account for age-related preferences in society. However, age has been shown to be an important equity-relevant characteristic. This study examines the willingness to pay (WTP) for health-related quality of life (QOL) gains in relation to the disease severity and age of patients, and the outcome of the disease.

METHODS

We obtained WTP estimates by applying contingent-valuation tasks in a representative sample of the public in The Netherlands (n = 2023). We applied random-effects generalized least squares regression models to estimate the effect of patients' disease severity and age, size of QOL gains, disease outcome (full recovery/death 1 year after falling ill), and respondent characteristics on the WTP.

RESULTS

Respondents' WTP was higher for more severely ill and younger patients and for larger-sized QOL gains, but lower for patients who died. However, the relations were nonlinear and context dependent. Respondents with a lower age, who were male, had a higher household income, and a higher QOL stated a higher WTP for QOL gains.

CONCLUSIONS

Our results suggest that-if the aim is to align resource-allocation decisions in healthcare with societal preferences-currently applied equity weights do not suffice.

Cost effectiveness of caplacizumab in acquired thrombotic thrombocytopenic purpura

Acquired thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease characterized by thrombotic microangiopathy leading to end-organ damage. The standard of care (SOC) treatment is therapeutic plasma exchange (TPE) alongside immunomodulation with steroids, with increasing use of rituximab ± other immunomodulatory agents. The addition of caplacizumab, a nanobody targeting von Willebrand factor, was shown to accelerate platelet count recovery and reduce TPE treatments and hospital length of stay in TTP patients treated in 2 major randomized clinical trials. The addition of caplacizumab to SOC also led to increased bleeding from transient reductions in von Willebrand factor and increased relapse rates. Using data from the 2 clinical trials of caplacizumab, we performed the first-ever cost-effectiveness analysis in TTP. Over a 5-year period, the projected incremental cost-effectiveness ratio (ICER) in our Markov model was $1 482 260, significantly above the accepted 2019 US willingness-to-pay threshold of $195 300. One-way sensitivity analyses showed the utility of the well state and the cost of caplacizumab to have the largest effects on ICER, with a reduction in caplacizumab cost demonstrating the single greatest impact on lowering the ICER. In a probabilistic sensitivity analysis, SOC was favored over caplacizumab in 100% of 10 000 iterations. Our data indicate that the addition of caplacizumab to SOC in treatment of acquired TTP is not cost effective because of the high cost of the medication and its failure to improve relapse rates. The potential impact of caplacizumab on health system cost using longer term follow-up data merits further study.

A systematic review of moral reasons on orphan drug reimbursement

BACKGROUND

The number of market approvals of orphan medicinal products (OMPs) has been increasing steadily in the last 3 decades. While OMPs can offer a unique chance for patients suffering from rare diseases, they are usually very expensive. The growing number of approved OMPs increases their budget impact despite their low prevalence, making it pressing to find solutions to ethical challenges on how to fairly allocate scarce healthcare resources under this context. One potential solution could be to grant OMPs special status when considering them for reimbursement, meaning that they are subject to different, and less stringent criteria than other drugs. This study aims to provide a systematic analysis of moral reasons for and against such a special status for the reimbursement of OMPs in publicly funded healthcare systems from a multidisciplinary perspective.

RESULTS

With a systematic review of reasons, we identified 39 reasons represented in 243 articles (scientific and grey literature) for and against special status for the reimbursement of OMPs, then categorized them into nine topics. Taking a multidisciplinary perspective, we found that most articles came from health policy (n = 103) and health economics (n = 49). More articles took the position for a special status of OMPs (n = 97) than those against it (n = 31) and there was a larger number of reasons identified in favour (29 reasons) than against (10 reasons) this special status.

CONCLUSION

Results suggest that OMP reimbursement issues should be assessed and analysed from a multidisciplinary perspective. Despite the higher occurrence of reasons and articles in favour of a special status, there is no clear-cut solution for this ethical challenge. The binary perspective of whether or not OMPs should be granted special status oversimplifies the issue: both OMPs and rare diseases are too heterogeneous in their characteristics for such a binary perspective. Thus, the scientific debate should focus less on the question of disease prevalence but rather on how the important variability of different OMPs concerning e.g. target population, cost-effectiveness, level of evidence or mechanism of action could be meaningfully addressed and implemented in Health Technology Assessments.

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.

Molecular Approaches for the Treatment of Pompe Disease

Glycogen storage disease type II (GSDII, Pompe disease) is a rare metabolic disorder caused by a deficiency of acid alpha-glucosidase (GAA), an enzyme localized within lysosomes that is solely responsible for glycogen degradation in this compartment. The manifestations of GSDII are heterogeneous but are classified as early or late onset. The natural course of early-onset Pompe disease (EOPD) is severe and rapidly fatal if left untreated. Currently, one therapeutic approach, namely, enzyme replacement therapy, is available, but advances in molecular medicine approaches hold promise for even more effective therapeutic strategies. These approaches, which we review here, comprise splicing modification by antisense oligonucleotides, chaperone therapy, stop codon readthrough therapy, and the use of viral vectors to introduce wild-type genes. Considering the high rate at which innovations are translated from bench to bedside, it is reasonable to expect substantial improvements in the treatment of this illness in the foreseeable future.

Variable clinical features and genotype-phenotype correlations in 18 patients with late-onset Pompe disease

Background

Pompe disease is a lysosomal storage disorder caused by the deficiency of enzyme acid alpha-glucosidase (GAA) which results in accumulation of glycogen, particularly in the skeletal, cardiac, and smooth muscles. The late-onset form with symptoms presenting in childhood through adulthood, is characterized by proximal muscle weakness, respiratory insufficiency, and unlike the infantile-onset form often with no cardiac involvement.

Methods

We report our experience with 18 adult patients (14 males/4 females) with Pompe disease, several of whom had unique findings and novel pathogenic variants. Patients ranged in ages from 22-74 years (mean 53.7 years) and were diagnosed at an age range of 11-65 years (mean 43.6 years), often after a history of progressive muscle disease of several years' duration. All 18 patients were treated with alglucosidase alfa (Lumizyme) and their response to treatment was monitored by measurements of their pulmonary function and muscle weakness, six-minute walk test (6MWT), and other functional studies.

Results

Genetic sequencing revealed that 16 out of 18 individuals had the common c.-32-13T>G splicing variant, and six patients, including two sibships had four novel pathogenic variants: c.1594G>A, c.2655_2656delCG, c.1951-1952delGGinsT, and c.1134C>G. A male with the c.1594G>A variant developed an intracerebral aneurysm at the age of 43 years treated with surgery. Two siblings with the c.2655_2656delCG developed very high antibody titers, one of whom developed a severe infusion reaction. Other clinical features included BiPAP requirement in twelve, tinnitus in seven, scoliosis in five, cardiomyopathy in three, one individual was diagnosed with a cerebral aneurysm who underwent successful Penumbra coil placement, and another individual was diagnosed with both Graves' disease and testicular cancer.

Conclusions

Our study illustrates significant variability in the range of clinical features, and the variable clinical response to enzyme replacement therapy. It also alerts us to the importance of careful monitoring and early management of complications. Possible genotype-phenotype associations with the novel mutations identified may emerge with larger studies.