Vagus nerve stimulation as adjunctive therapy in patients with difficult-to-treat depression (RESTORE-LIFE): study protocol design and rationale of a real-world post-market study

BACKGROUND

Depressive illness is associated with significant adverse consequences for patients and their families, and for society. Clinical challenges are encountered in the management of patients suffering from depression whether they are designated difficult-to-treat or treatment-resistant. Prospective serial depression treatment trials have shown that less than 40% of patients with major depressive disorder remit with an initial pharmacotherapy trial, and a progressively smaller proportion of patients remit with each subsequent trial. For patients who suffer from difficult-to-treat depression (DTD), treatments should focus on patient-centred symptom control, patient functioning, and improving patient quality of life. Among the treatment options for patients with DTD is Vagus Nerve Stimulation (VNS) Therapy. VNS Therapy involves intermittent electrical stimulation of the left cervical vagus nerve and has been shown to be efficacious for long-term management of patients with DTD.

METHODS

RESTORE-LIFE is a prospective, observational, multi-site, global post-market study intended to assess short-, mid-, and long-term effectiveness and efficiency outcomes in a 'real-world' setting among patients with DTD treated with adjunctive VNS Therapy. A minimum of 500 patients will be implanted with a VNS Therapy System at up to 80 global sites. Eligible patients will participate in a baseline visit between 1 and 6 weeks before device implant and will be followed for a minimum of 36 months and a maximum of 60 months. The diagnosis of depression and comorbid disorders will be determined using the Mini-International Neuropsychiatric Interview (MINI). The primary endpoint is response rate, defined as a decrease of ≥50% in Montgomery Åsberg Depression Rating Scale (MADRS) total score from baseline to 12 months post-implant.

DISCUSSION

A standardized approach in the management of DTD may not be appropriate for the treatment of such a complex heterogenous patient population. This study has been designed to evaluate whether VNS Therapy meaningfully improves and sustains clinical and depressive symptom outcomes in patients with DTD. This study will investigate the durability of VNS response in DTD and utility of VNS for long-term disease management of DTD. In addition, the study results will potentially clarify clinical, functional, and health economic questions in a real-world patient population with DTD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03320304. Registered 25 October 2017.

Amelioration of intractable epilepsy by adjunct vagus nerve stimulation therapy in a girl with a CDKL5 mutation

We report the case of on an 8-year-old girl with a cyclin-dependent kinase-like 5 mutation and who underwent vagus nerve stimulation (VNS) therapy for 2years. She had developed epilepsy at the age of 6months and had severe developmental delays. Initially, she had tonic and tonic-clonic seizures; however, around the age of 5years, she also developed epileptic spasms. These seizures were never completely controlled by conventional medical treatments. At the age of 7, after VNS initiation, her seizure frequency markedly reduced, and abnormal electrical activities on her electroencephalography tests strikingly decreased. Moreover, using questionnaires, we confirmed an improvement in her quality of life in the fields of alertness and activity. Although the efficacy of VNS therapy for patients with intractable epilepsy associated with a genetic anomaly has not been fully established, adjunctive VNS therapy may widen the scope of treatment choices available to these patients.