This exploratory study assessed the potential cost-effectiveness of TOMAC therapy for the treatment of refractory RLS. TOMAC was found to provide good value for money, meaningfully improving patient outcomes at an overall net cost difference that renders TOMAC a cost-effective intervention, compared to sham and baseline, and both in the shorter-term and—if therapy is maintained—even more so over the lifetime horizon. Findings of the comprehensive additional scenarios suggest cost-effectiveness findings might be even more favorable than reported for the base case, which was based on a set of conservative assumptions on costs, utility, and treatment effect.
As demonstrated in the randomized, double-blind, sham-controlled RESTFUL study, TOMAC stimulation therapy provides a safe, effective, and novel noninvasive peripheral nerve stimulation that provides a valuable treatment alternative for medication-refractory RLS patients. The therapy has recently received FDA authorization and, as such, additional real-world experience and data will become available in the future that will help to further corroborate the therapy’s clinical value proposition. Additionally, the publication and conduct of a 24-week extension study provided further insight into the therapy’s long-term safety and effectiveness [
14]. In addition, scenario analyses explored relying upon these data further confirm TOMAC to be a cost-effective intervention.
The objective of the current study was to conduct an exploratory rather than a definitive cost-effectiveness analysis. As such, it provides an early perspective about the main drivers of TOMAC’s expected health-economic value and early orientation about the potential cost-effectiveness. These insights—particularly the relevance of quality of life improvement with achieved symptom relief and resulting reductions in resource utilization—will be useful to inform future more definitive analyses that should be conducted as more experience is gained with the therapy and further study data become available.
The analysis is subject to several limitations. First, the assumed effectiveness was based on the 4-week results of the RESTFUL study, the protocol-defined time frame for the primary analysis of the therapy’s safety and effectiveness. Projecting this short-term effect over lifetime is subject to significant uncertainty. However, follow-up data from the RESTFUL study beyond 4 weeks demonstrate an increase in treatment effect rather than decrease over time [
14]. Furthermore, prior cost-effectiveness analyses of neurostimulation treatments and therapies, such as continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea, do rely on comparable short-term data to project long-term effects. The current study, however, explored the potential effect of reduced and increased effectiveness in a threshold analysis and presented a scenario based on 24-week outcomes reported in the recent extension study. Second, as in any patient-used therapy and in neurostimulation treatments, issues of therapy adherence and potential non-response to treatment affect long-term patient outcomes and costs and need to be properly reflected. The current study assumed 80% therapy compliance in the long-term, which seems well supported by data available to date. In this context, it is important to keep in mind that patients treated with TOMAC are medication-refractory RLS patients who have exhausted other treatment options and who have a substantial maintained disease burden. It can reasonably be expected that these patients will continue to use the therapy if it provides sufficient symptom improvement. The assumption that the overall cohort effect will only gradually be affected by 20% of the cohort discontinuing treatment (implemented in the analysis by assuming patients off therapy retain 50% of the prior modeled benefit) seems reasonable for this very reason—those discontinuing therapy are more likely than not to be non-responders, and their results already affected the therapy effectiveness of the full cohort. Nevertheless, alternative assumptions of zero and full benefit maintained in those discontinuing therapy were explored and did not materially change the results. Third, quality of life and cost data were derived based on previously published studies and survey data. While these were large sample studies in reasonably comparable RLS cohorts, this approach introduces uncertainty. However, this was addressed by exploring different sources for the IRLS-to-EQ-5D mapping and choosing the more conservative source for the base case. Future, more definitive TOMAC cost-effectiveness studies will benefit from study-collected EQ-5D quality of life data. Further, the analysis relied on data from Durgin et al. to establish a relationship between IRLS severity and utilization of provider visits, ED treatments, and inpatient admissions, but a conscious choice was made to down-adjust the unit cost data per visit, ED treatment, and hospitalization. This deviation from previously reported cost was grounded in the authors’ assessment that Medicare-incurred costs might be lower, as supported by a review of the current fee schedule and recent Medicare cost data. The use of these lower cost assumptions in the base case can be regarded as conservative, as using the data as previously reported in the Durgin study leads to much more sizable savings with TOMAC therapy and, in consequence, to substantially more favorable cost-effectiveness findings that even included TOMAC dominance. Furthermore, in the absence of an established DME reimbursement for TOMAC, the analysis assumed a manufacturer-provided cost estimate of $7500 plus monthly incurred cost of $75 per device. While it is likely that reimbursement will be provided in this magnitude, some uncertainty remains. This was addressed by conducting additional threshold and scenario analyses. Future studies will benefit from TOMAC trial-collected information about resource utilization and costs in both arms of the study. Additionally, detailed data about the contemporary long-term RLS-specific health care utilization and costs, possibly analyzed and provided from current ongoing RLS registries in the US, could further benefit TOMAC and—more broadly—any future cost-effectiveness evaluation of RLS therapies. Finally, RLS-specific healthcare costs are primarily driven by prescription and outpatient treatment costs, which would suggest that the model assumption of no change in prescription utilization with TOMAC therapy may be conservative [
10]. For example, recent data suggest a potential reduction in opioid utilization for patients on TOMAC treatment [
19]. Broadly, a reduced need for pharmacologic treatments might also lower the risk of augmentation or side effects for patients receiving standard treatments, which could lead to additional benefits not accounted for in the current analysis [
1,
20‐
22]. Further evidence is warranted to model any potential reduction with necessary certainty.