Intercept Epilepsy Control System

Intercept

Intercept™ Epilepsy Control System - Medtronic

The Intercept™ Epilepsy Control System (alternately called Medtronic DBS for epilepsy - DBS = deep brain stimulation) is an implant device that consists of a generator and wires that terminate in leads which are implanted in the thalamus. The generator sends electrical impulses to the thalamus according to programmed parameters.

Efficacy

Medtronic has conducted a prospective, randomized, double-blind study called SANTE (stimulation of the anterior nucleus of the thalamus in epilepsy) with 110-150 patients at 15-17 sites in the U.S. and Canada. Preliminary results were presented at the American Epilepsy Society (AES) Annual Meeting in 2008:

The results from the SANTE study showed that stimulating the left and right anterior nucleus of the thalamus – the brain’s central message and relay station – with Medtronic’s DBS therapy for epilepsy in conjunction with epilepsy medications produced a statistically significant median percent reduction in seizures compared to a no stimulation control group at the end of the blinded phase of the study (38 percent in the treatment groups vs. 14.5 percent in the control group with both groups continuing on their epilepsy medications without change during this phase). The results from long-term follow up during the trial show even greater reductions in seizures for the majority of patients. Key data highlights:
  • Of the 87 study participants who completed the diaries through month 13, 40 percent experienced a 50 percent or greater reduction in their baseline rate of seizures 13 months after implant.
  • Of the 86 study participants who had at least three months of data from long-term follow up, 60 percent experienced a 50 percent or greater reduction in their baseline rate of seizures. These long-term follow up results represent outcomes from the last three months of available data for each patient (ranged from 12 to 49 months after implant with median follow up of 31 months).
  • During this same long-term follow-up period (last three months of data for each patient), median seizure frequency was reduced by approximately two-thirds, nine percent of study participants had no seizures and 19 percent experienced a greater than 90 percent reduction in seizure frequency.

Potential Adverse Events

Medtronic's press release for the SANTE trial did not disclose how many patients experienced adverse events, but did mention:

... Twenty-two percent of the total reported events were related to stimulation, hardware or procedure and three percent of all adverse events were serious device-related effects. The infection rate was 10.9 percent and the rate of asymptomatic intracranial hemorrhage was 1.3 percent per lead implant. While there was a significantly higher incidence of spontaneously self-reported depression, memory impairment, and anxiety in the active group compared to the control group during the blinded phase, most events resolved spontaneously or with changes in medication or stimulation parameters. Objective neuropsychological assessment at the end of the Blinded Phase did not confirm any statistical differences between the active and control groups.

I left the score for the chart at zero because the risk (rate) is still unknown (or at least not reported).

Cost

Costs won't be known until the device is approved by the FDA and available to the public, but I'm reasonably confident that the surgical procedure is cost prohibitive without insurance. It scores an 8 for a general approximation of out of pocket expenses (for what insurance does not cover).

Type

I expect the Intercept system to work similar to the VNS - on a mostly passive basis once settings have been ramped up to the desired therapeutic level. It may require surgeries to replace batteries every so many years (depending upon model and settings), and patients may be able to manually activate the device, but I scored it as a continuous system with passive participation because that is how it is intended to operate most of the time.

Latency

It appears from the SANTE trial that the full benefits of the system are not realized until after at least one year.

Special Notes

None.

This page last modified September 9, 2019.

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