Research In Brief
This article was originally published in The Gray Sheet
Executive Summary
VNS postmarket study: Multicenter, double-blind randomized dosing study (D-21) showed that at 50 weeks, treatment with Cyberonics' VNS Therapy vagus nerve stimulation system improved overall depression symptoms by 32.4%-42%, based on the Montgomery-Asberg Depression Rating Scale, the firm reports May 27. The study was a condition of FDA approval in 2005 for patients with chronic and recurrent treatment-resistant depression (1"The Gray Sheet" July 25, 2005). D-21 compared adjunctive VNS Therapy administered at three stimulation levels (low, medium or high) in 331 patients for 22 weeks. Patients receiving high stimulation did not show significantly greater improvement than those receiving low or medium stimulation at the end of the 22-week acute phase. The study design allowed patients in low and medium groups to receive increased levels of stimulation after 22 weeks