Cost-effectiveness of natalizumab in multiple sclerosis: an updated systematic review

Untackling the economics of multiple sclerosis: A systematic review of economic evaluations of disease-modifying therapies indicated for multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS) comprises a chronic, neurodegenerative, and inflammatory illness of the central nervous system that affects 2.8 million people worldwide. MS is only treatable, and to this direction, the disease armamentarium has been significantly enriched with new agents, albeit with burgeoning costs and engulfed by uncertainty. The scope of this review is to assess the efficiency of MS agents.

METHODS

We performed a systematic literature review, spanning from 2000 to 2023 on adult patients with any form of MS, receiving any MS indicated modality and whose outcome was ICUR and ICER. The methodological quality of the studies was assessed with the Quality of Health Economics Studies tool.

RESULTS

We identified 57 studies that met the inclusion criteria. Studies were hailing from 20 countries and a multitude of methodological approaches were documented across several types of MS. A substantial level of divergence regarding results was noted. Country setting, study perspective (societal vs payer) the selection of the benchmark treatment, data extrapolation beyond the reported timeframe of the trial and time horizon of the model exerted a substantial impact on the results. Dimethyl fumarate was consistently interrelated with a positive cost-effectiveness ratio. The same applies for fampridine, while Cladribine was proved to be a dominating agent. Ocrelizumab also evinced efficiency. The same applies for the early data of Siponimod and ofatumumab, however the breadth of their studies lags compares to other agents, and these results have to be further corroborated. On the contrary Interferons demonstrated a non-efficient profile and their use as a comparative benchmark arm brought about several complications regarding the incremental financial aspect of economic evaluations, since they are commonly used as such. The results of fingolimod and natalizumab studies are embroiled in uncertainty. Moreover, the efficiency factor was positively correlated by earlier access of patients to these products, rather than delayed one. Result discrepancies among the same country were also imputed to the adopted utility and disutility values and the methodological approach for data extrapolation. Results were sensitive to an array of factors. Among them, the effectiveness of the products, coupled with the cost of the agents emerged as the most important drivers. Uncertainty was further compounded by several other parameters such as discounting, efficacy waning, horizon of the study, disability base rate and utility of the patients. We also outlined that the efficiency of product is pertinent to the disease type. Results such as dominance must be interpreted with caution since in certain cases a dominating agent was proved to be as such by capitalizing on marginal incremental health gains, compared to the standard comparative treatment.

CONCLUSIONS

An increasing body of evidence consisting of economic evaluations for MS was retrieved. These studies exhibited high quality, however, the consistency regarding results was impaired.

How have Economic Evaluations in Relapsing Multiple Sclerosis Evolved Over Time? A Systematic Literature Review

INTRODUCTION

The introduction of disease-modifying therapies (DMTs) for relapsing multiple sclerosis (RMS) over the last two decades has prompted the economic assessments of these treatments by reimbursement authorities. The aim of this systematic literature review was to evaluate the modeling approach and data sources used in economic evaluations of DMTs for RMS, identify differences and similarities, and explore how economic evaluation models have evolved over time.

METHODS

MEDLINE®, Embase®, and EBM Reviews databases were searched using Ovid® Platform from database inception on 25 December 2019 and subsequently updated on 17 February 2021. In addition, health technology assessment agency websites, key conference proceedings, and gray literature from relevant websites were screened. The quality of included studies was assessed using the Drummond and Philips checklists.

RESULTS

A total 155 publications and 30 Health Technology Assessment (HTA) reports were included. Most of these were cost-utility analysis (73 studies and 25 HTA reports) and funded by medicines manufacturers (n = 65). The top three countries where studies were conducted were the USA (n = 29), the UK (n = 16), and Spain (n = 10). Studies predominantly used Markov cohort models (94 studies; 25 HTAs) structured based on the Expanded Disability Status Scale (EDSS) with 21 health states (20 studies; 12 HTA reports). The London Ontario and British Columbia data sets were commonly used sources for natural history data (n = 33; n = 13). Twelve studies and ten HTAs from the UK assumed a waning of DMT effect over the long term, while this was uncommon in studies from other countries. Nineteen studies adjusted for multiple sclerosis (MS)-specific mortality estimates, while 18 studies used data from the national life table without adjustment. Studies prominently referred to mortality data that were about two decades old. The data on treatment effect was generally obtained from randomized controlled trials (43 studies; 7 HTAs) or from published evidence synthesis (23 studies; 24 HTAs). Utility estimates were derived from either published studies and/or supplemented with data from RCTs. Most of the models used the lifetime horizon (n = 37) with a 1-year cycle length (n = 63).

CONCLUSION

As expected, similarities as well as differences were observed across the different economic models. Available evidence suggests models should continue using the Markov cohort model with 21 EDSS-based states, however, allowing the transition to a lower EDSS state and assuming a sustained treatment effect. With reference to the data sources, models should consider using a contemporary MS-specific mortality data, recent natural history data, and country-specific utility data if available. In case of data unavailability, a sensitivity analysis using multiple sources of data should be conducted. In addition, future models should incorporate other clinically relevant outcomes, such as the cognition, vision, and psychological aspects of RMS, to be able to present the comprehensive value of DMTs.

Predictors of Health Utility in Relapsing-Remitting and Secondary-Progressive Multiple Sclerosis: Implications for Future Economic Models of Disease-Modifying Therapies

BACKGROUND

Decision-analytic models used in economic evaluations of disease-modifying therapies for relapsing-remitting multiple sclerosis (RRMS) have characterized disease progression and accrue quality-adjusted life-years from utility values based on the Expanded Disability Status Scale (EDSS), the occurrence of relapses, and progression to secondary-progressive multiple sclerosis (SPMS). The EDSS, used to characterize disability progression, has several limitations. If the EDSS is the only disability measure used in economic evaluations, the long-term clinical and economic implications of disease-modifying therapies may not be properly assessed.

OBJECTIVE

The objective of this study was to explore if supplementary disability measures including the Timed 25-Foot Walk (T25FW), 9-Hole Peg Test (9HPT), and Paced Auditory Serial Addition Test (PASAT) significantly contribute additional information on health utility in RRMS and SPMS otherwise not captured by the EDSS and relapses and, therefore, should be considered in future economic evaluations of disease-modifying therapies.

METHODS

Short-Form Six-Dimension utility scores were derived from the RAND 36-Item Health Survey 1.0 individual-level data available in the Multiple Sclerosis Outcome Assessment Consortium (MSOAC) Placebo Database. Repeated-measures mixed-effects models were conducted to estimate the effects of EDSS, T25FW, 9HPT (dominant and non-dominant hand), PASAT, and relapses on changes in utility over time, controlling for demographics.

RESULTS

A higher level of EDSS, longer time to complete the T25FW test, and a recent relapse were significant predictors of lower utility in people with RRMS and SPMS. 9HPT and PASAT were not significant predictors.

CONCLUSIONS

This study suggests that in addition to EDSS and recent relapses, T25FW significantly predicts utility in RRMS and SPMS. These findings support the use of T25FW to supplement the EDSS and the occurrence of relapses to characterize the course of disease progression and to more accurately accrue quality-adjusted life-years in future economic evaluations of disease-modifying therapies for the treatment of RRMS.

Incorporating patients' preferences in the value assessment of disease-modifying therapies for multiple sclerosis: a narrative review

Introduction: Despite the increasing role of patients in the US healthcare system, patients have yet been engaged in the value assessment of their treatments, including disease-modifying therapies (DMTs) for multiple sclerosis (MS). The objectives of this review were therefore to summarize existing studies on cost-effectiveness analysis (CEA) with quality-adjusted life years (QALYs) and patients' preferences of DMTs for MS, and to discuss how to incorporate patients' preferences into the value assessment of DMTs.Area covered: We reviewed previous systematic reviews and conducted further search until November 2020 for studies on CEA with QALYs and patients' preferences of DMTs for MS. We identified the outcomes that were assessed or valued in the CEA studies and the DMT attributes that were important to patients with MS.Expert opinion: Our literature review showed that the studies using CEA with QALYs failed to capture some important DMT attributes, e.g., route and frequency of administration, identified in the studies on the patients' preferences. Various approaches were available for incorporating the patients' preferences in the value assessment of DMTs for MS. We supported this incorporation, which subsequently would increase patient access to preferred DMTs.

Modeling Approaches in Cost-Effectiveness Analysis of Disease-Modifying Therapies for Relapsing-Remitting Multiple Sclerosis: An Updated Systematic Review and Recommendations for Future Economic Evaluations

BACKGROUND

Numerous cost-effectiveness analyses (CEAs) of disease-modifying therapies (DMTs) for relapsing-remitting multiple sclerosis (RRMS) have been published in the last three decades. Literature reviews of the modeling methods and results from these CEAs have also been published. The last literature review that focused on modeling methods, without country or time horizon in the inclusion criteria, included studies published up to 2012. Since then, new DMTs have become available, and new models and data sources have been used to assess their cost effectiveness.

OBJECTIVE

The aim of this systematic review was to provide a detailed and comprehensive description of the relevant aspects of economic models used in CEAs of DMTs for RRMS, to understand how these models have progressed from recommendations provided in past reviews, what new approaches have been developed, what issues remain, and how they could be addressed.

METHODS

EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), the National Health System (NHS) Economic Evaluations Database, the Health Technology Assessment (HTA) Database, and EconLit were searched for cost-effectiveness studies of DMTs for RRMS that used decision-analytic models, published in English between 1 January 2012 and 24 December 2017. The inclusion criteria were as follows: being a full economic evaluation, a decision-analytic model was used, the target population concerned adult patients with RRMS, and being available in full-text format. Studies were not excluded based on the methodological quality. The background information of the included studies, as well as specific information on the components of the economic models related to the areas of recommendation from previous reviews were extracted.

RESULTS

Twenty-three studies from ten countries were included. The model structure of these studies has converged over time, characterizing the course of disease progression in terms of changes in disability and the occurrence of relapses over time. Variations were found in model approach; data sources for the natural course of the disease and comparative efficacy between DMTs; number of lines of treatment modeled; long-term efficacy waning and treatment discontinuation assumptions; type of withdrawal; and criteria for selecting adverse events. Main areas for improvement include using long-term time horizons and societal perspective; reporting relevant health outcomes; conducting scenario analyses using different sources of natural history and utility values; and reporting how the model was validated.

CONCLUSION

The structure of economic models used in CEAs of DMTs for RRMS has converged over time. However, variation remains in terms of model approach, inputs, and assumptions. Though some recommendations from previous reviews have been incorporated in later models, areas for improvement remain.

Disease-Modifying Therapies for Multiple Sclerosis: A Systematic Literature Review of Cost-Effectiveness Studies

INTRODUCTION AND OBJECTIVE

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. MS is considered incurable; however, disease treatment has advanced significantly over the past several decades with the introduction of disease-modifying therapies (DMTs). The current study reviewed the cost-effectiveness analyses of DMTs in relapsing-remitting MS (RRMS) patients.

METHODS

A systematic literature search of bibliographic databases was conducted to identify economic evaluations published after 2007. The relevant population, intervention, comparators, outcomes, and study design (PICOS) were considered. The outcomes of interest were incremental cost-effectiveness ratios (ICERs), net monetary benefits, incremental benefits, and incremental costs. The Consolidated Health Economic Evaluation Reporting Standards (CHEERS) statement was used to assess the reporting quality of published studies.

RESULTS

A total of 1370 potentially relevant citations were identified, of which 33 published articles and four Health Technology Assessment (HTA) reports prepared for the UK were included in the final analysis. Almost all studies were based on a health economic model and considered RRMS as the phase of disease at study entry. The studies were conducted in 10 different countries, with approximately 50% based in the US. Study outcomes were rarely comparable due to the different settings, input data, and assumptions. Even within the same country, the discrepancy between study criteria was considerable. The compliance with reporting standards of the CHEERS statement was generally high.

CONCLUSIONS

Internationally, a large number of health economic assessments of DMTs in RRMS were available, yielding difficult to compare, and at times conflicting, results.