Abstract
INTRODUCTION: Vagus nerve stimulation activates neuroimmune reflexes that modulate systemic inflammation and may represent a novel non-pharmacologic treatment modality for autoimmune diseases like rheumatoid arthritis (RA). In a 3-month first-in-human, double-blind trial, 50% of patients with drug-refractory RA improved clinically, two patients achieved remission, and pro-inflammatory cytokines declined by 30-50% with daily stimulation. The current study is a 36-month extension of that trial, designed to assess the sustained safety and efficacy of the neuroimmune modulation device in patients with multidrug-refractory RA. METHODS: Patients (N = 14) with active RA and prior insufficient response to at least two different biological or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) with at least two mechanisms of action were implanted with a novel neuroimmune modulation device that stimulates the cervical vagus nerve, treated for 12 weeks, and then assessed for safety and clinical effectiveness in an open-label 36-month extension. RESULTS: Eleven patients completed the extension study through month 36. Patients had previously failed an average of 4.8 different drugs, with 64% (9/14) having failed a tsDMARD before enrolling in the study. The median change in clinical disease activity index (CDAI) score from day 0 to month 36 was - 17.8 (SEM 4.9). At month 36, 64% (7/11) of patients achieved a CDAI response that met or exceeded the minimal clinically important difference. Two of these seven patients were treated with daily stimulation alone, while five patients combined stimulation with an adjunctive b/tsDMARD. No device-related infections, cardiac events, surgical revisions, or device explants were reported. Two adverse events related to the device occurred in a single patient: a mild sore throat and moderate tenderness near the implant site. These events were non-serious, anticipated, and resolved. CONCLUSION: In this first-in-human long-term extension study, neuroimmune modulation was well tolerated among patients with multidrug-refractory RA, with reductions of clinical disease activity that were maintained through 36 months.