Healthcare Stakeholder Perspectives on a Value Assessment Approach for Duchenne Muscular Dystrophy Therapies

Purpose

Traditional value assessment frameworks are challenged in comprehensively assessing the societal value new therapies bring to individuals with rare, progressive, genetic, fatal, neuromuscular diseases such as Duchenne muscular dystrophy (DMD). The objective of this study was to identify how value assessment frameworks may need to be adapted to measure the value to society of DMD therapies.

Patients and Methods

Three stakeholder groups (6 patient advocates, 4 clinicians, 3 health economists; N = 13) participated in semi-structured interviews around the International Society for Pharmacoeconomics and Outcomes Research's Value Flower, which includes elements to consider within value assessments of healthcare technologies.

Results

All stakeholders agreed that traditional value assessment frameworks based on the quality-adjusted life year (QALY) are narrow and will undervalue new DMD therapies. All stakeholders expressed some level of concern that using the QALY as a key metric of value discriminates against patients with severe progressive diseases and disabilities. Some stakeholders saw value in using the QALY for cross-disease comparisons in resource-constrained environments if the methodology was appropriate. All stakeholders recommended considering additional elements of value in decision-making around new DMD therapies. These elements reflect: economic and humanistic costs incurred by patients, caregivers, and families with Duchenne, such as indirect out-of-pocket costs, lost productivity, and family spillovers; meaningful attributes for individuals with disabilities and high unmet need, such as severity of disease, value of hope, and real option value; and factors that contribute to improvements in population health, such as insurance value, equity, and scientific spillovers.

Conclusion

These findings highlight the need to expand traditional value assessment frameworks and take a holistic approach that incorporates the perspectives of individuals with Duchenne, caregivers, clinicians, and health economists when assessing the societal value of new DMD therapies. Broadening value assessment will prevent restricted or delayed access to therapies for individuals with Duchenne.

Discriminatory Properties of Quality-Adjusted Life Year Based Cost-Effectiveness Analyses for Patients With Disabilities: A Duchenne Muscular Dystrophy Case Study

OBJECTIVES

Quality-adjusted life years (QALYs) have been challenged as a measure of benefit for people with disabilities, particularly for those in low-utility health states or with irreversible disability. This study examined the impact of a QALY-based assessment on the price for a hypothetical treatment for Duchenne muscular dystrophy (DMD), a progressive, genetic neuromuscular disease.

METHODS

A previously published, 5-state model, which analyzed treatments for early ambulatory (EA) DMD patients, was replicated, validated, and adapted to include early nonambulatory (ENA) DMD patients. The model was used to assess a QALY-based threshold price (maximum cost-effective price) for a hypothetical treatment for 13-year-old ENA and 5-year-old EA patients (initial health states with lower and higher utility, respectively). All inputs were replicated including willingness-to-pay thresholds of $50 000 to $200 000/QALY.

RESULTS

In contrast to EA patients, ENA patients had a 98% modeled decline in QALY-based threshold price at a willingness-to-pay of $150 000/QALY or higher, despite equal treatment benefit (delayed progression/death). At $100 000/QALY or lower, net nontreatment costs exceeded health benefits, implying any treatment for ENA patients would not be considered cost-effective, even at $0 price, including an indefinite pause in disease progression.

CONCLUSIONS

For certain severe, disabling conditions, traditional approaches are likely to conclude that treatments are not cost-effective at any price once a patient progresses to a disabled health state with low utility value. These findings elucidate theoretical/ethical concerns regarding potential discriminatory properties of traditional QALY assessments for people with disabilities, particularly those who have lost ambulation or have other physical limitations.

Barriers to diverse clinical trial participation in Duchenne muscular dystrophy: Engaging Hispanic/Latina caregivers and health professionals

BACKGROUND

Despite the increasing availability of clinical trials in Duchenne muscular dystrophy, racial/ethnic minorities and other populations facing health disparities remain underrepresented in clinical trials evaluating products for Duchenne. We sought to understand the barriers faced by Hispanic/Latino families specifically and underrepresented groups more generally to clinical trial participation in Duchenne.

METHODS

We engaged two participant groups: Hispanic/Latino caregivers of children with Duchenne in the US, including Puerto Rico, and health professionals within the broader US Duchenne community. Caregiver interviews explored attitudes towards and experiences with clinical trials, while professional interviews explored barriers to clinical trial participation among socio-demographically underrepresented families (e.g., low income, rural, racial/ethnic minority, etc.). Interviews were analyzed aggregately and using a thematic analysis approach. An advisory group was engaged throughout the course of the study to inform design, conduct, and interpretation of findings generated from interviews.

RESULTS

Thirty interviews were conducted, including with 12 Hispanic/Latina caregivers and 18 professionals. We identified barriers to clinical trial participation at various stages of the enrollment process. In the initial identification of patients, barriers included lack of awareness about trials and clinical trial locations at clinics that were less likely to serve diverse patients. In the prescreening process, barriers included ineligibility, anticipated non-compliance in clinical trial protocols, and language discrimination. In screening, barriers included concerns about characteristics of the trial, as well as mistrust/lack of trust. In consent and recruitment, barriers included lack of timely decision support, logistical factors (distance, time, money), and lack of translated study materials.

CONCLUSIONS

Numerous barriers hinder participation in Duchenne clinical trials for Hispanic/Latino families and other populations experiencing health disparities. Addressing these barriers necessitates interventions across multiple stages of the clinical trial enrollment process. Recommendations to enhance participation opportunities include developing clinical trial decision support tools, translating prominent clinical trials educational resources such as ClinicalTrials.gov, fostering trusting family-provider relationships, engaging families in clinical trial design, and establishing ethical guidelines for pre-screening potentially non-compliant patients.

Decreased quality of life in Duchenne muscular disease patients related to functional neurological and cardiac impairment

In this prospective study involving 37 Duchenne muscular dystrophy (DMD) patients aged 8-18 years and older, we examined the impact of neurological and cardiac factors on quality of life (QoL). Our findings revealed a negative correlation between upper limb movement and overall mobility, self-service, and usual activities. Ambulatory and non-ambulatory DMD patients showed significant differences in mobility-related parameters. Cardiac evaluations demonstrated associations between mitral annular plane systolic excursion (MAPSE) and mobility-related aspects. The PEDSQL 3.0 neuromuscular model questionnaire further highlighted age-related and movement-related correlations with QoL. The loss of ambulatory status and reduced upper limb movement were negatively associated with QoL, while upper limb movement positively correlated with septal MAPSE. However, no significant associations were found between MAPSE and anxiety/depression. These findings underscore the multifaceted impact of DMD on QoL and emphasize the importance of considering both neurological and cardiac factors in comprehensive patient care.

Assessing validity of the EQ-5D-5L proxy in children and adolescents with Duchenne muscular dystrophy or spinal muscular atrophy

OBJECTIVE

To assess the psychometric properties of the EuroQol-5-Dimension five-level instrument (EQ-5D-5L) proxy in caregivers of children and adolescents with Duchenne muscular dystrophy (DMD) or spinal muscular atrophy (SMA).

METHOD

Data were collected using the EQ-5D-5L proxy for individuals with DMD or SMA, as reported by their caregivers. Ceiling and floor effects, reliability (Cronbach's alpha), convergent and divergent validity (Spearman's correlation coefficient and Bland-Altman plot) and known-group validity (analysis of variance) was used to assess the instrument's psychometric properties.

RESULTS

Totally, 855 caregivers completed the questionnaire. Significant floor effects were observed for most dimensions of the EQ-5D-5L in both SMA and DMD samples. The EQ-5D-5L was strongly correlated with the hypothesized subscales of the SF-12, which confirmed satisfactory convergent and divergent validity. The EQ-5D-5L can significantly differentiate between impaired functional groups for individuals, demonstrating satisfactory discriminative ability. The agreement between the EQ-5D-5L utility and EQ-VAS scores was poor.

CONCLUSIONS

Based on the measurement properties assessed in this study, the EQ-5D-5L proxy is a valid and reliable tool for measuring the health-related quality of life of individuals with DMD or SMA rated by caregivers. Further studies should examine the content validity of the EQ-5D as well as the performance of its young version in these two patient groups.

Draft Guidance for Industry Duchenne Muscular Dystrophy, Becker Muscular Dystrophy, and Related Dystrophinopathies - Developing Potential Treatments for the Entire Spectrum of Disease

Background

Duchenne muscular dystrophy (DMD) and related dystrophinopathies are neuromuscular conditions with great unmet medical needs that require the development of effective medical treatments.

Objective

To aid sponsors in clinical development of drugs and therapeutic biological products for treating DMD across the disease spectrum by integrating advancements, patient registries, natural history studies, and more into a comprehensive guidance.

Methods

This guidance emerged from collaboration between the FDA, the Duchenne community, and industry stakeholders. It entailed a structured approach, involving multiple committees and boards. From its inception in 2014, the guidance underwent revisions incorporating insights from gene therapy studies, cardiac function research, and innovative clinical trial designs.

Results

The guidance provides a deeper understanding of DMD and its variants, focusing on patient engagement, diagnostic criteria, natural history, biomarkers, and clinical trials. It underscores patient-focused drug development, the significance of dystrophin as a biomarker, and the pivotal role of magnetic resonance imaging in assessing disease progression. Additionally, the guidance addresses cardiomyopathy's prominence in DMD and the burgeoning field of gene therapy.

Conclusions

The updated guidance offers a comprehensive understanding of DMD, emphasizing patient-centric approaches, innovative trial designs, and the importance of biomarkers. The focus on cardiomyopathy and gene therapy signifies the evolving realm of DMD research. It acts as a crucial roadmap for sponsors, potentially leading to improved treatments for DMD.

Estimating health state utilities in Duchenne muscular dystrophy using the health utilities index and EQ-5D-5L

BACKGROUND

The progression of Duchenne muscular dystrophy (DMD) is characterized by loss of ambulation, respiratory insufficiency, cardiomyopathy, and early mortality. DMD profoundly impacts health-related quality-of-life (HRQoL). However, few health state utility data exist; published utilities tend to be derived from small samples for a limited number of health states and are often based on caregiver-reported patient health status. This study estimated utility values for varied clinical and functional health states in DMD, based on patient-reported health status.

METHODS

Individuals with DMD in the US aged 12-40 years completed the EQ-5D (5-level) and Health Utilities Index (HUI) preference-based instruments. Based on responses to a clinical questionnaire, participants self-classified into functional health states according to level of lower and upper limb function, use of respiratory support, and presence of cardiomyopathy. Mean [standard deviation (SD)] utility and EQ-5D visual analogue scale (VAS) scores were estimated according to health state; and median (interquartile range) attribute levels calculated to understand which domains of health are most severely affected in DMD.

RESULTS

Of 63 males with DMD, mean (SD) age was 19.8 (6.1) years and 11 (17.5%) were ambulatory. Mean (SD) utility values were 0.92 (0.08; HUI2), 0.84 (0.20; HUI3), and 0.84 (0.13; EQ-5D) for ambulatory patients without cardiomyopathy (n = 10). For non-ambulatory patients with moderately impaired upper limb function, night and daytime ventilation without cardiomyopathy, mean (SD) utilities were 0.49 (0.07) for the HUI2, 0.16 (0.15) for the HUI3 and 025 (0.14) for the EQ-5D. Mean (SD) VAS scores for the same health states were 91 (9) and 83 (21), respectively. In addition to impairments in mobility/ambulation, and self-care, attributes like usual activities and pain also showed notable effects of DMD.

CONCLUSIONS

In DMD, although a relationship between disease progression and HRQoL is observed, there is large variability in utility within functional health states, and across instruments. Utility values for less severe non-ambulatory health states described by level of upper limb function are novel. These utility values, derived based on direct patient feedback rather than from caregiver report, are relevant to individuals of varying functional statuses and augment scarce DMD-specific utility data.

EQ-5D and SF-6D health utility scores in patients with spinal and bulbar muscular atrophy

OBJECTIVE

This study assessed patient-reported health-related quality of life (HRQoL) using two generic preference-based measures in Chinese patients with spinal and bulbar muscular atrophy (SBMA) and identified demographic and clinical determinants of health utility scores in this population.

METHODS

This study used cross-sectional data of 212 Chinese patients with SBMA who completed both the EQ-5D and SF-6D. Association between response to EQ-5D and SF-6D dimensions was examined using Spearman's correlation coefficient, and the association between the two utility scores was assessed using Pearson's correlation coefficient. The variations in utility scores across patients in different subgroups were compared using one-way ANOVA. Bland-Altman (B-A) plot was used to assess the agreement of utility scores between EQ-5D and SF-6D. A multivariate Tobit regression model was employed to estimate the association between utility scores and the presence of symptoms and chronic conditions.

RESULTS

The mean utility scores for the EQ-5D and SF-6D were 0.54 and 0.56, respectively. The hypothesized correlation between the EQ-5D and SF-6D dimensions ranged from 0.31 to 0.58, and the correlation between their utility scores was 0.64. An acceptable agreement between EQ-5D and SF-6D utility scores was identified by B-A plot. Patients with chronic diseases, misdiagnosis, high financial burden, and several clinical symptoms were highly likely to report a low health utility score.

CONCLUSIONS

This study is the first to investigate the HRQoL of patients with SBMA worldwide. The estimated health utility scores for EQ-5D and SF-6D can be utilized as baseline data for future cost-utility analyses of SBMA-related interventions.

People Diagnosed with Myasthenia Gravis have Lower health-related quality of life and Need More Medical and Caregiver Help in Comparison to the General Population: Analysis of Two Observational Studies

INTRODUCTION

Myasthenia gravis (MG) is a neuromuscular disease causing extreme muscular fatigue, triggering problems with vision, swallowing, speech, mobility, dexterity, and breathing. This analysis intended to estimate the health-related quality-of-life impact, the medical burden, and the need for caregiver help of people diagnosed with MG.

METHODS

MyRealWorld-MG (MRW) is an observational study among adults diagnosed with MG in 9 countries. The General Population Norms (POPUP) observational study enrolled representative members of the general population in 8 countries. In both digital studies, respondents entered personal characteristics and provided data on medical conditions, EQ-5D-5L, HUI3, MG-Activities of Daily Living (MG-ADL), sick leave, caregiver help, and medical care utilization.

RESULTS

In MRW (n = 1859), 58.4% of respondents had moderate-to-severe MG. Average utility values were lower in MRW versus POPUP (0.739 vs. 0.843 for EQ-5D-5L; 0.493 vs. 0.746 for HUI3), and declined with more severe disease (0.872, 0.707, 0.511 EQ-5D-5L utilities and 0.695, 0.443, 0.168 HUI3 utilities for mild, moderate, and severe MG, respectively). Taking sick leave in the past month was 2.6 times more frequent among people diagnosed with MG compared to the general population (34.4% vs. 13.2%) and four times more people diagnosed with MG reported needing help from a caregiver (34.8% vs. 8.3%). Use of medical care was twice as likely in MRW in comparison with POPUP (51.9% vs. 24.6%).

CONCLUSION

This direct comparison of people diagnosed with MG and the general population using two large international studies revealed significant negative impact of MG. Results were consistent across all outcomes, in all countries.

A comprehensive qualitative framework for health-related quality of life in Duchenne muscular dystrophy

PURPOSE

Duchenne muscular dystrophy (DMD) is a rare x-linked neuromuscular condition predominantly affecting boys and men. There is a paucity of research qualitatively detailing the lived experience of health-related quality of life (HRQoL) for people with DMD. The aim of this study was to identify a comprehensive framework for better understanding HRQoL in DMD.

METHODS

Eighteen boys and men (aged 7 to ≥ 40 years) with DMD were recruited from charity Duchenne UK, a DMD support group, and 5 UK National Health Service Trusts. Semi-structured interviews were conducted using a topic guide informed by a review into HRQoL in DMD. Generic, preference-based, patient-reported outcome measures (PROs) were used as prompts. Interviews were audio recorded, transcribed verbatim and analysed using framework analysis.

RESULTS

Thirty-seven themes were coded, within seven categories. Six categories were conceptualised as components of HRQoL (autonomy, daily activities, feelings and emotions, identity, physical aspects, social relationships) and one considered an input (healthcare, support, and environment). Three additional themes were used to code feedback on the generic PROs (CHU-9D, EQ-5D, HUI). Social relationships received most coverage in the data and was noted as an omission from the PROs.

CONCLUSION

A 30-item framework for HRQoL in DMD has been developed, which was used as input into a new condition-specific HRQoL PRO and preference-based measure: the DMD-QoL. The data has value in its own right in highlighting the lived experience of HRQoL for people with DMD and as a barometer for assessing the content of HRQoL PROs for use in DMD.

A Comparison of Caregiver and Patient Preferences for Treating Duchenne Muscular Dystrophy

Background and Objectives

Caregivers routinely inform medical and regulatory decision making in rare pediatric diseases. While differences in treatment preferences across caregivers and patients have been observed for Duchenne muscular dystrophy, this evidence was limited by small samples of patients and results were confounded by patient age and disease progression. We tested caregiver and patient preference concordance for treating Duchenne.

Methods

Preferences and demographic/clinical information from 115 caregivers and 107 patients were collected in an international study (response = 80%) using a previously developed discrete-choice experiment consisting of 12 experimentally controlled choice tasks. Each task presented two profiles that varied across four attributes: disease progression, drug failure probability, kidney damage risk, and fracture risk. Caregivers and patients were matched 1:1 based on patient age. We tested for concordance across each task and by comparing caregivers’ and patients’ maximum acceptable risk of drug failure, kidney damage, and fracture for a slowing of disease progression.

Results

The final analysis included 77 caregivers and 77 patients. No differences were observed in nationality (p = 0.969), disease stage (p = 0.180), or demographic/clinical factors (p = 0.093–0.857); however, patients were more optimistic (p = 0.030). Caregivers and patients chose similarly across tasks (p = 0.101–0.993). To slow disease progression by 1 year, caregivers and patients would tolerate a 9% and 11% increase in drug failure probability, respectively (p = 0.267). Alternatively, they would accept a 3% and 4% increase in the risk of kidney damage (p = 0.719) or a 15% and 20% increase in the risk of fracture (p = 0.534).

Conclusions

Caregivers and patients had concordant preferences for treating Duchenne. Providers and regulators can trust both caregiver and patient report of preferences to inform medical decision making.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40271-022-00574-y.

Health-Related Quality of Life and Perceived Burden of Informal Caregivers of Patients with Rare Diseases in Selected European Countries

Most of rare disease (RD) patients are assisted in their homes by their family as informal caregivers, causing a substantial burden among family members devoted to care. The role of informal caregivers has been associated with increased levels of stress, poor physical/mental health and impaired HRQOL. The present study assessed the impact on HRQOL and perceived burden of long-term informal caregiving, as well as the inter-relationships of individuals affected by different RD in six European countries, taking advantage of the data provided by the BURQOL-RD project (France, Germany, Italy, Spain, Sweden and UK). Correlation analysis was used to explore the relation between caregiver HRQOL and caregiver burden (Zarit Burden Interview). Multinomial logistic regression models were used to explore the role of explanatory variables on each domain of caregivers HRQOL measured by EQ-5D. Caregivers' HRQOL is inversely correlated with burden of caring. Mobility dimension of EQ-5D was significantly associated with patients age, time devoted to care by secondary caregivers, patient gender and patient utility index. Patients' age, burden scores and patient utility index significantly predict the capacity of caregivers to perform activities of daily living. Employed caregivers are less likely of reporting 'slight problems' in pain/discomfort dimensions than unemployed caregivers. The EQ-5D instrument is sensitive to measure differences in HRQOL between caregivers with different levels of burden of care.

Unmet Therapeutic Needs of Non-Ambulatory Patients with Duchenne Muscular Dystrophy: A Mixed-Method Analysis

OBJECTIVE

Duchenne muscular dystrophy has been a launching pad for patient-focused drug development (PFDD). Yet, PFDD efforts have largely neglected non-ambulatory patients. To support PFDD efforts in this population, we primarily sought to understand the needs of non-ambulatory Duchenne patients and, secondarily, to examine these needs in the context of the PUL-PROM-a validated patient-reported outcome measure of upper limb functioning.

METHODS

Non-ambulatory Duchenne patients or their caregivers from eight countries answered open-ended survey questions about patients' needs related to their most significant symptoms and important benefits of new treatments. The PUL-PROM was used to evaluate patients' upper limb functioning and was compared to data collected on non-ambulatory stage and quality of life. We thematically analyzed open-ended data, descriptively analyzed close-ended data, and compared themes by non-ambulatory stage.

RESULTS

The study included 275 participants. Mean patient age was 24. Most patients were early-stage non-ambulatory (67%). Thematic analysis identified three congruent themes between significant symptoms and important benefits of new treatments: muscle functioning, especially upper limb function; body system functioning; and quality of life. Muscle functioning and body system functioning were endorsed more frequently in responses from early- and late-stage patients, respectively. Mean PUL-PROM total score was 22 with higher scores in early-stage patients (p ≤ 0.001). Upper limb function positively correlated with quality of life (r = 0.42, p ≤ 0.001).

DISCUSSION

Non-ambulatory Duchenne patients want new treatments that improve upper limb functioning and body system functioning, and not exclusively regaining ambulation. The PUL-PROM can be used as a patient-centric measure that accounts for the needs of later-stage Duchenne patients.

Factors associated with the health-related quality of life among people with Duchenne muscular dystrophy: a study using the Health Utilities Index (HUI)

Background

Data on health state utility in Duchenne muscular dystrophy (DMD) are few. This study estimated mean utility values by age, ambulatory status and over time, and investigated which aspects of health-related quality-of-life (HRQoL) are most strongly associated with utility in DMD.

Methods

Data from placebo-treated ambulant boys with DMD with exon 51 skip amenable mutations, (NCT01254019), were included. Ambulatory function assessments were conducted at baseline and every 12 weeks for the trial duration. Family member proxies completed the Health Utility Index (HUI) at baseline, 24 and 48 weeks; and HUI3 and HUI2 utility values were summarized. Changes in HUI attribute level over time, and predictors of changes in utility, were explored.

Results

Sixty-one boys (mean [range] age of 8.0 [5–16] years) were included in the analysis. Mean baseline utilities were 0.82 (HUI3) and 0.87 (HUI2); and utilities were 0.35 (HUI3) and 0.55 (HUI2) after loss of ambulation (LOA, where applicable). Over the follow-up period mean utility declined more among the older versus younger boys. Pain accounted for the highest proportion of variability (42%) in change in HUI3 utility from baseline to week 48, while for HUI2, self-care (39%) did. After LOA, change in ambulation levels explained 88% of the decline in mean HUI3 utility and change in mobility levels explained 66% of the decline in mean HUI2 utility.

Conclusions

Utility values among this sample were higher than previously published estimates. In younger boys utility remained relatively stable, but older boys and those losing ambulation experienced important declines over follow-up.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12955-022-02001-0.

Diagnostic experiences of Duchenne families and their preferences for newborn screening: A mixed-methods study

Duchenne muscular dystrophy is the most common form of muscular dystrophy diagnosed in childhood but is not routinely screened for prenatally or at birth in the United States. We sought to characterize the diagnostic experiences of families and describe their preferences for newborn screening (NBS). We conducted a registry-based survey of families with Duchenne and Becker muscular dystrophy that included open- and closed-ended questions regarding the journey to a diagnosis, preferences for when to learn of a diagnosis, and how knowledge of a diagnosis would impact life decisions. Open-ended responses were analyzed thematically, and closed-ended responses were analyzed descriptively. Sixty-five families completed the survey. The average ages of first concern and diagnosis were 2 and 4 years, respectively. One-third of families (30%) indicated that they would prefer to receive a diagnosis in the newborn period irrespective of treatment options available, and nearly all of the remaining families (93%) indicated that they would want to learn about a diagnosis if there were treatments that worked well during the newborn period. All families (100%) indicated that a diagnosis in the newborn period would impact life decisions. We identified three overarching themes, which described the stages of the diagnostic journey, including having concerns about the child, seeking answers, and receiving the diagnosis. NBS can facilitate improved health outcomes through early access to care, and inform families on major health and nonhealth decisions. The preferences and experiences of families and other stakeholders should be considered when determining the potential value and benefit of expanding NBS programs.

Assessing the value of orphan drugs using conventional cost-effectiveness analysis: Is it fit for purpose?

Conventional cost-effectiveness analysis—i.e., assessing pharmaceuticals through a cost per quality-adjusted life year (QALY) framework—originated from a societal commitment to maximize population health given limited resources. This "extra-welfarist" approach has produced pricing and reimbursement systems that are not well- aligned with the unique considerations of orphan drugs. This framework has been slow to evolve along with our increased understanding of the impact of rare diseases, which in turn has complicated the assessment of orphan drugs meant to treat rare diseases. Herein, we (i) discuss the limitations of conventional cost-effectiveness analysis as applied to assessing access to, as well as the pricing and reimbursement of, orphan drugs, (ii) critically appraise alternative and supplemental approaches, and (iii) offer insights on plausible steps forward.

Quantifying the Burden of Hyperphagia in Prader-Willi Syndrome Using Quality-Adjusted Life-years

BACKGROUND

Prader-Willi syndrome (PWS) is a rare disease associated with cognitive impairment, hypotonia, hyperphagia (an insatiable hunger), and obesity. Therapies that target hyperphagia are in development, but understanding the value of these therapies to inform patient-focused drug development (PFDD) requires valid data on disease burden. We estimated disease burden by measuring and comparing quality-adjusted life-years (QALYs) for 3 PWS health states relevant to current PFDD initiatives.

METHODS

Time trade-off (TTO) and a visual analog scale (VAS) were used to elicit PWS caregivers' values for 3 fixed health states for a standardized patient described with (1) untreated PWS, (2) PWS with controlled obesity, and (3) PWS with controlled obesity and hyperphagia. We excluded participants who left at least 1 TTO or VAS question blank or incomplete (noncompleters) and respondents who reported the same answer for all TTO scenarios (nontraders). The remaining group of respondents (traders) were used for all primary analyses. We assessed validity and bias of QALY estimates by comparing differences in health state valuations, treatment priorities, and characteristics among respondents who did and did not complete the TTO.

RESULTS

A total of 458 respondents completed the survey, including 226 traders, 93 nontraders, and 139 noncompleters. Traders valued untreated PWS at 0.69 QALYs, PWS with controlled obesity at 0.79 QALYs, and controlled hyperphagia/obesity at 0.91 QALY (P < 0.01 for differences among health state values). Reported VAS ratings were similar for traders versus nontraders for untreated PWS (38.64 vs 38.95, P = 0.89) and PWS with controlled obesity (57.36 vs 55.14, P = 0.35) but varied for PWS with controlled obesity and hyperphagia (70.70 vs 64.46, P = 0.02). Exclusion of noncompleters did not introduce obvious bias because traders and noncompleters were similar in treatment priorities and characteristics. The exclusion of nontraders did not meaningfully alter mean or distribution of valuations.

CONCLUSIONS

This study found that avoiding hyperphagia decreases the burden of PWS and that these results are robust, even once imposing strict inclusion criteria. Use of fixed health states to estimate QALYs addresses many of the complexities of measuring disease burden in rare and pediatric conditions, indicating the potential value of this approach to inform premarket decision makers in identifying outcome importance. (Clin Ther. 2021;XX:XXX-XXX) © 2021 Elsevier HS Journals, Inc.