Enabling Opioid Dose Reduction for Refractory Restless Legs Syndrome through Adjunctive Tonic Motor Activation (TOMAC) Therapy
Mark Buchfuhrer1, Stephanye Rodriguez2, Jonathan Charlesworth2
1Stanford University School of Medicine, 2Clinical Research, Noctrix Health, Inc.
Objective:
Tonic motor activation (TOMAC) is an external neuromodulation device that has shown promising efficacy for treating Restless Legs Syndrome (RLS). Here, we investigated if TOMAC could enable opioid dose reduction for RLS patients.
Background:
There is a large population of RLS patients who are refractory to treatment with FDA approved medications. Whereas experts recommend off-label opioids as an effective long-term treatment for refractory RLS, there is also significant interest among patients and clinicians to reduce opioid dosage to minimize risks.
Design/Methods:
We report interim analysis from an open-label multicenter clinical study (NCT04698343) recruiting adults taking a maximum of 60 morphine milligram equivalents (MME) to treat refractory RLS. On average, participants (N=11) had RLS symptoms for 30.8 years, were refractory to 3.2 medications, and had taken opioids for 7.9 years. Total opioid dose was reduced iteratively. Participants self-administered 30-minute sessions of TOMAC bilaterally over the peroneal nerve whenever RLS symptoms presented. To assess changes to RLS symptoms, the Clinician Global Impressions-Improvement (CGI-I) score and International RLS Rating Scale (IRLS) total score were assessed at the end of each dose reduction relative to baseline. An opioid dose reduction was considered well-tolerated if CGI-I score remained below 6.
Results:
During adjunctive TOMAC treatment, the mean well-tolerated opioid dose reduction was 29.0% (SEM: 6.5%, range: 0-75%) from 40.1 to 28.7 MME over an average of 2.6 weeks. At this reduced dosage, the mean CGI-I score was 4.1 (SEM: 0.4; 4.0 indicates no change) and the average IRLS score change was +1.6 (SEM: 1.4), indicating minimal changes to RLS symptoms.
Conclusions:
These preliminary results suggest that adjunctive TOMAC enables opioid dose reduction for patients with refractory RLS without increases to RLS symptoms. By enabling lower opioid doses, TOMAC could reduce the risks associated with long-term treatment of refractory RLS.