UCLA: epilepsy 'brain pacemaker' won't outpace drugs

University of California, Los Angeles and Advanced Bionics have developed a trigeminal nerve stimulation device to treat epilepsy. The device is a potential alternative to drug treatment and has several advantages over vagus nerve stimulation. However, device makers in this market face challenges due to the comparatively late arrival of nerve stimulation and limited patient reimbursement issues.

Trigeminal nerve stimulation (TNS) uses a 'brain pacemaker' to stimulate the trigeminal nerve. The device's stimulator and electrodes can be worn externally or implanted.

Results from a recent pilot human clinical trial show that four of seven participants experienced a 50% or greater reduction in seizure frequency when using an external stimulator for at least three months. These results warrant further investigation into the safety and efficacy of TNS for epilepsy and the University of California, Los Angeles (UCLA) aims to recruit 25 patients for a follow-up study.

Despite the introduction of several anti-epileptic drugs over the past decade, approximately 20% to 30% of patients continue to suffer from uncontrolled seizures. However, the use of neurosurgery as an alternative to drug treatment is only suitable for a minority of patients as it is largely limited to those with partial seizures. Furthermore, the invasive nature of surgery and its associated risks are prohibiting factors.

Given the limits of this approach, and since uncontrolled epilepsy may lead to diminished cognition, the development of effective non-drug treatments for this patient group represents a large unmet need.

Cyberonics' vagus nerve stimulation (VNS) system is presently the only nerve stimulation-based treatment available to epilepsy patients. However, TNS holds two key advantages over VNS; the device can be tested externally to gauge the results (and is, therefore, minimally invasive), and it stimulates both sides of the brain. Furthermore, due to the vagus nerve's role in controlling heart and lung function, stimulation of the trigeminal nerve is likely to be less risky as it innervates only the face.

However, even if the efficacy of TNS is demonstrated in subsequent trials, the late positioning of nerve stimulation in the epilepsy market, in comparison to drug treatments, will limit market penetration. Furthermore, the inability of many patients to gain full reimbursement for nerve stimulation may prohibit their access to this treatment.

Therefore, while TNS has significant patient potential in the US, its distance from the market and challenges to market penetration mean drug therapy will remain the mainstay of symptomatic epilepsy treatment.