Last week at the American Epilepsy Society Meeting in Boston, Medtronic and NeuroPace released results of clinical trials studying the benefits of the firms’ competing Deep Brain Stimulation (DBS) systems to control symptoms in patients suffering from severe epilepsy. The findings seem to foreshadow the future in which the technology might become a standard treatment option for patients who continue to develop seizures despite adequate medication regiments, and in some cases, vagus nerve stimulation or even ablative surgery.
From Medtronic’s announcement:
The results of the study show improvement over time with median (mid-point) reduction in seizure frequency of 41 percent at one year, 56 percent at two years, and 68 percent at three years of DBS therapy, in conjunction with antiepileptic medications, compared to baseline. Of the original 110 patients who received DBS implants in the trial, 91 remain active in the study, including some who have received DBS therapy for more than five years. At the time of this data analysis, 102 patients had completed two years and 57 had completed three years of therapy. In addition, 14 patients (13 percent) experienced seizure free intervals ranging from six months to more than four years.
The study, known as SANTE® (Stimulation of the Anterior Nucleus of the Thalamus in Epilepsy), is a prospective, randomized, double-blind pivotal study to evaluate the use of DBS therapy for patients with medically refractory epilepsy with partial-onset seizures, a form of epilepsy that does not respond well to antiepileptic drugs.
The types of adverse events reported in the study were consistent with known adverse events associated with epilepsy and implanted DBS systems. There were no serious unanticipated device-related adverse events. At the conclusion of the unblinded phase of the study (first 13 months), 4.2 percent of adverse events (a total of 34 events) were serious and device-related. That rate declined over time. Of the 34 events, the most frequent serious device-related events were lead(s) not within the target (nine events) and implant site infection (eight events). Depression and memory impairment were reported more frequently in active stimulation patients compared to no stimulation (controls) although objective neuropsychological assessment did not show any statistical differences between active or no stimulation (control) groups.
The SANTE study involves stimulating the left and right anterior nucleus of the thalamus – the brain’s central message and relay station – with Medtronic DBS Therapy for Epilepsy in conjunction with epilepsy medications. Patients in the study have had epilepsy for an average of 22 years and 54 percent of the 110 implanted patients had previously undergone resective surgery and/or vagal nerve stimulation therapy. Benefit was seen in patients with prior history of vagal nerve stimulation or previous epilepsy surgery as well as patients without such history.
From a statement by NeuroPace:
The trial demonstrated a statistically significant reduction in seizure frequency in the treatment group (responsive stimulation active) as compared to the sham stimulation group (responsive stimulation inactive). During the last two months of the three month blinded evaluation period of the study, people in the treatment group experienced a mean percentage reduction of 29 percent in their disabling seizures compared to 14 percent reduction for those in the sham stimulation group. In the long term, open label period of the trial, at least 12 weeks of data were available for 171 study participants; 47 percent of these subjects experienced a 50 percent or greater reduction in their seizure frequency based on their most recent 12 weeks of data, as compared to their baseline.
The trial also demonstrated a serious adverse event rate less than comparative surgical procedures. There were no serious unanticipated device related adverse events reported in the trial. There was no difference between the treatment and sham stimulation groups when comparing the rate of adverse events, including depression, memory impairment and anxiety.
Press releases: Pivotal Study of Medtronic Deep Brain Stimulation Therapy Shows Long-Term Reduction in Seizure Rate in Patients with Severe Epilepsy; Pivotal Trial Data Demonstrate NeuroPace RNS System Reduced Seizures in People with Epilepsy…
Product pages: Medtronic DBS…; NeuroPace RNS System…
Flashbacks: Medtronic to Seek FDA Approval of Brain Stimulation Device for Epilepsy; Neuropace Implantable Epilepsy Device Showing Positive Signs in Initial Clinical Study