This is a publication undertaken by a health technology assessment organisation. For further information please contact the agency using the contact details in the Correspondence Address field.

This Assessment will review the available evidence to determine if vagus nerve stimulation (VNS) therapy is effective for treatment-resistant depression. This Assessment updates the prior TEC Assessment of VNS for the same indication.

Since the last TEC Assessment, there have been no studies reporting clinical outcomes on any new or different patients. Data from the case series and clinical trials have been reanalyzed to show what proportions of patients who respond at one time are still responders at a subsequent time point. However, this information by itself does not provide evidence of the efficacy of VNS beyond that provided by the original observational comparison of VNS versus treatment as usual.

Based on the available evidence, the Blue Cross and Blue Shield Association Medical Advisory Panel made the following judgments about whether vagus nerve stimulation (VNS) for the indication of treatment-resistant depression meets the Blue Cross and Blue Shield Association Technology Evaluation Center (TEC) criteria.

1. The technology must have final approval from the appropriate governmental regulatory bodies. The NeuroCybernetic Prosthesis System (NCP, Cyberonics, Inc.) received approval of its Premarket Application (PMA) to market from the U.S. Food and Drug Administration (FDA) on July 16, 1997, for treatment-refractory seizures. The device was approved for use in conjunction with drugs or surgery "as an adjunctive treatment of adults and adolescents over 12 years of age with medically refractory partial onset seizures." On July 15, 2005, the VNS Therapy System received final PMA approval by the FDA for "adjunctive long-term treatment of chronic or recurrent depression for patients 18 years of age or older who are experiencing a major depressive episode and have not had an adequate response to 4 or more adequate antidepressant treatments."

2. The scientific evidence must permit conclusions concerning the effect of the technology on health outcomes. The clinical trials reviewed above report weak evidence that does not demonstrate efficacy.

3. The technology must improve the net health outcome; and

4. The technology must be as beneficial as any established alternatives. The available evidence does not permit conclusions regarding the effect of VNS therapy on health outcomes or its effect compared with alternative therapies.

5. The improvement must be attainable outside the investigational settings. Whether VNS therapy for treatment-related depression improves health outcomes has not yet been determined in the investigational setting. For the above reasons, VNS therapy for the indication of treatment-resistant depression does not meet the TEC criteria.