St. Jude Medical (St. Paul, Minnesota) reported the results of a pilot study on its Libra Deep Brain Stimulation (DBS) neurostimulation device for treating deep depression. The company got the nod from FDA for an investigational device exemption (IDE) to begin enrollment in a clinical study of DBS earlier this year (Medical Device Daily, Feb. 12, 2008).
Results of the pilot study, which were presented yesterday at the American Psychiatric Association (APA; Arlington, Virginia) meeting in Washington, found that six months after the procedure, 56% of the 26 patients in the study experienced at least a 40% decrease in depressive symptoms. Patients' symptoms were measured using a standardized test, the Hamilton Rating Scale for Depression.
Brodmann Area 25 (BA25) is an area of the brain called the perfrontal cortex. Scientists have known for some time that it participates in networks that govern personal and social behavior, emotion, and decision making. A series of PET scans and neuroimaging experiments have demonstrated that this area of the brain is overactive during periods of profound negative mood, or sadness.
"What the researchers found is that, that particular part of the brain Brodmann Area 25 (BA25) appears to become overactive when the person is experience feelings of sadness and depression," Kathleen Janasz, a spokeswoman for St. Jude Medical, told Medical Device Daily.
On average, the study participants had suffered from depression for more than 20 years; they were disabled and unable to work at the time of enrollment. The study also found that at their most recent psychiatric evaluation, 78% of the patients experienced at least a 40% decrease in depressive symptoms. Three of the study patients are considered to be in remission. Eight patients have re-engaged in life activities such as work, school, relationships and travel.
Conducted at three leading Canadian academic medical centers, the study expands and supports the research of Helen Mayberg, MD, and Andres Lozano, MD, which was published in Neuron in March.
The Libra DMS system facilitates in the treatment by delivering mild electrical current and looks and operates much like a pacemaker, except that instead of sending pulses to the heart, it sends pulses to the brain.
The Libra system includes a neurostimulator, leads, and extensions that are surgically implanted. The DBS leads are surgically positioned in the brain and the neurostimulator is typically placed under the skin in the chest. After the system is in place, a health care provider uses the programmer to program the neurostimulator.
In addition to the implanted components, the Libra DBS system includes a programmer and a controller, which are not implanted. The programmer is used to customize the stimulation produced by the neurostimulator. The controller is used to turn the neurostimulator on and off.
The device was originally developed by Advanced Neuromodulation Systems (Houston), which St. Jude acquired in 2005 (Medical Device Daily, Nov. 13, 2005).
"We're the only company to be granted IDE by the FDA for deep brain stimulation," Janasz said. "In the U.S. alone there are 4 million patients who suffer from depression that isn't treatable. We are talking about patients who are profoundly ill. This isn't someone who is suffering from mild depression. These are patients who have tried medication to forms shock therapy — every one of these patients has tried a minimum of 12 medications and it didn't work for them. Our overall goal is to have a viable treatment and help these patients."
While St. Jude says it is the only company to have been granted an IDE for DBS, it isn't the only company developing devices for DBS.
The companies it shares a space with include Medtronic (Minneapolis), Boston Scientific (Natick, Massachusetts) and Northstar Neurosience (Seattle).
Cyberonics (Houston) previously has been perhaps the most active participant in the sector, developing its Vagus Nerve Stimulation (VNS) system for forms of depression resistant to other therapies and billing its use as a therapy for treatment-resistant depression (TRD). That use of the VNS technology originally focused on treatment of epilepsy — has been panned by critics as a company creation of a disease target, since the term could simply be applied to any disease resistant to standard treatments.
Cyberonics won FDA approval for the TRD application, but the therapy has not won acceptance in the medical and psychiatric communities, with rejection of reimbursement coverage by the Centers for Medicare & Medicaid Services being a major roadblock.
Last August, Cyberonics said it was refocusing its efforts on the epilepsy market (MDD, Aug. 31, 2007).